Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: uniquorn on September 11, 2019, 11:43:21 AM

Title: MOSAiC news
Post by: uniquorn on September 11, 2019, 11:43:21 AM
The MOSAiC expedition begins on the Sep20.

MOSAiC - Multidisciplinary drifting Observatory for the Study of Arctic Climate

It could be the largest-scale Arctic research expedition of all time: in September 2019 the German research icebreaker Polarstern will depart from Tromsø, Norway and, once it has reached its destination, will spend the next year drifting through the Arctic Ocean, trapped in the ice. A total of 600 people from 19 countries, who will be supplied by other icebreakers and aircraft, will participate in the expedition – and several times that number of researchers will subsequently use the data gathered to take climate and ecosystem research to the next level. The mission will be spearheaded by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).

The expedition programme is here (
More information here:

Image of the general set-up
Area of MOSAiC start location overlaid onto unihamburg amsr2-uhh, aug1-sep11
edit: tidied up a bit and updated Polarstern position image
Title: Re: MOSAiC news
Post by: Neven on September 11, 2019, 06:22:35 PM
I think this is a very important expedition, so I'm going to sticky it for a while.
Title: Re: MOSAiC news
Post by: uniquorn on September 11, 2019, 06:59:44 PM
A virtual CTD cast of the proposed start area(outlined in red) using mercator salinity(0-300m),  temperature (0m-100m), 0m temperature anomaly and sea surface height with bathymetry, sep10
A CTD or Sonde is an oceanography instrument used to measure the conductivity, temperature, and pressure of seawater (the D stands for "depth," which is closely related to pressure). The reason to measure conductivity is that it can be used to determine the salinity.
Title: Re: MOSAiC news
Post by: Jim Hunt on September 11, 2019, 07:21:29 PM
There is also a dedicated MOSAiC web site. Here's the sea ice section:

and here is the news section:

Stefan Hendricks amongst others is "Tweeting" about the expedition:
Title: Re: MOSAiC news
Post by: uniquorn on September 11, 2019, 08:41:54 PM
Thanks Jim. edit: While this is great news in the longer term, hopefully there will be some near real time data
Title: Re: MOSAiC news
Post by: blumenkraft on September 12, 2019, 10:00:52 AM
Title: Re: MOSAiC news
Post by: Neven on September 12, 2019, 04:36:23 PM
Meereisportal ( will also offer lots of data:

Auf werden daher exklusiv Daten und Informationen der MOSAiC-Meereisphysik bereitgestellt, um die aktuelle Meereissituation, die Drift der MOSAiC-Station sowie erste Ergebnisse von Bojen und anderen Messverfahren in Karten- und Datenmaterial bereitzustellen.

Im Informationsbereich von unter werden aktuelle Informationen zur MOSAiC-Expedition mit Fokus auf die Meereisphysik gegeben.
In zwei Beiträgen werden unter anderem atmosphärischen Reanalyse-Daten der vergangenen Jahre benutzt, um eine wahrscheinliche Entwicklung des Meereises vorherzusagen. Mit Hilfe des AWI-Vorhersagesystems (Sea Ice Outlook) werden möglichen Eisbedingungen (Eisbedeckung und Eisdicke) in der geplanten Startregion bestimmt und erklärt wie dieses System die Routenplanung von FS Polarstern unterstützen kann. In einem zweiten Beitrag wird eine Analyse der möglichen Drift der MOSAiC-Station im Winter 2019/20 durch die zentrale Arktis, basierend auf Drift Satellitendaten der vergangenen dreizehn Jahre beschrieben. Weiterhin berichtet bis zum Beginn des Drift-Experimentes, wenn FS Polarstern an einer geeigneten Meereisscholle festgemacht und das Camp aufgebaut worden ist, der AWI-Meereisticker zweimal wöchentlich über die Eisbedingungen in der Arktis und die Route, die FS Polarstern nehmen wird.

Im Datenportal von ist ein spezieller MOSAiC-Bereich www.meereisportal/mosaic/daten/ aufgebaut worden, in dem unterschiedliche tagesaktuelle Karten, Daten und Zusatzinformationen zur Expedition rund um das Thema Meereis dargestellt sind und auch heruntergeladen werden können. Folgende Produkte werden hier angeboten:

Meereiskonzentration Detailkarte der MOSAiC Expedition
Vergleich täglicher Eiskanten
Polarstern Drift basierend auf „klimatologischer“ Driftvorhersage und -analyse
Polarstern Drift-Szenarien (einschließlich „Nahe“-Echtzeit)
Aktuelle Bilder zur Eisbewegung vom Schiffsradar

Auf diese Weise kann man von jedem Ort auf der Welt quasi „live vor Ort sein“, alles rund um das Thema Meereis dieser Expedition verfolgen und diese einmalige Expedition begleiten und miterleben!

Mit besten Grüßen vom gesamten MOSAiC-Meereisteam,

Renate Treffeisen und Klaus Grosfeld
Title: Re: MOSAiC news
Post by: Phil. on September 12, 2019, 04:45:21 PM
Unfortunately their English page doesn't exist yet.
Title: Re: MOSAiC news
Post by: uniquorn on September 12, 2019, 05:33:40 PM
Sea Ice Detail map of the MOSAiC expedition
Comparison of daily ice edges (or ridges)
Polarstern drift based on "climatological" drift prediction and analysis
Polarstern drift scenarios (including "near" real time)
Multi-satellite product
sea ​​ice buoys
Current pictures of ice movement from the ship's radar
Title: Re: MOSAiC news
Post by: Jim Hunt on September 12, 2019, 06:33:01 PM
Unfortunately their English page doesn't exist yet.

The data page is available in English:

I happily downloaded the image below. It's quite big! Let me know if a more modest version would be preferable.
Title: Re: MOSAiC news
Post by: uniquorn on September 12, 2019, 10:49:03 PM
osi-saf ice drift over summer for the mosaic startup area, jun-sep11 (every 2 days to reduce file size).
Title: Re: MOSAiC news
Post by: uniquorn on September 13, 2019, 04:34:57 PM
13 drift estimates based on 2005-2017drift starting from 14 different locations within the start area by Dr Thomas Krumpen. The start location is marked with a star.
Polarstern drift

The ship’s potential drift route can be roughly estimated in advance by reconstructing the course that the ice followed from the starting point in past years. This involves the use of satellite data, which depicts the ice drift in the Arctic on a daily basis. The analytical tool used for the ice drift is called IceTrack and was developed at the AWI. In addition to various types of satellite data (ice drift, ice concentration, ice thickness), reanalysis data – which provides insights into temperature, wind speed and atmospheric pressure in the Arctic – is taken into account. In this way, not only the ice drift in the past years can be reconstructed for individual potential starting points, but all key atmospheric factors influencing the ice can also be included. A comprehensive description of these methods was recently released in connection with a study that investigated changes in the Transpolar Drift as a result of global warming (source: Nature).

The data portal displays drift scenarios for various potential starting points. Each figure shows the drift trajectories for the years 2005 – 2017 for the respective starting point (e.g. 85°N / 130°E). For the purposes of the drift analysis, the starting date is always 1 October of the respective year. The ice’s progress in the course of a year is reconstructed using the IceTrack algorithm, and the calculation is only stopped when the ice cover at the respective position drops below a certain threshold (50 %), at which point we have to assume that the MOSAiC ice floe would have melted. The colours used for the trajectories symbolise the month for the respective position.
Title: Re: MOSAiC news
Post by: uniquorn on September 14, 2019, 05:00:02 PM
The mosaic website provides a link to the International Arctic Buoy Programme. Daily data from the buoy table is available here

For buoys that are still reporting, raw plots of the data are available by clicking the buoy's id. More detailed plots are available for buoys that have stopped reporting. These more detailed plots include satellite derived buoy quantities such as surface temperature and ice concentration, and also reanalysis quantities from MERRA, including atmospheric temperature. The reanalysis products actually use buoy data in their calculations, but they have expert filtering techniques for eliminating the use of bad data in their final product. Comparing raw buoy data to their final product is therefore a good way of estimating buoy data quality, though differences between the interpolated field and any particular buoy data value is to be expected.

All data provided here are raw, and only include quatities of atmospheric interest: Sea Level Pressure (BP), Surface Temperature (Ts), and Atmospheric Temperature(Ta). Many buoys also contain interesting ice and ocean quantities, accessible via their respective sites. IMBs have high resolution temperature readings of the ice layer, for example, while UpTempOs typically have a 60m thermistor string to sample ocean temperatures. ITPs actually profile the water column down to 500m or more.
Title: Re: MOSAiC news
Post by: Jim Hunt on September 15, 2019, 10:33:39 AM
Cross posted from the melting season thread (,2591.msg228697.html#msg228697).

I am reliably informed that amongst the equipment to be deployed will be four type 3 seasonal ice mass balance buoys:

Title: Re: MOSAiC news
Post by: Jim Hunt on September 17, 2019, 01:57:55 AM
More information just in from Don Perovich re IMB buoys:

In addition to the SIMBs there will be other buoys studying the atmosphere, ocean, and ice motion.

Our data will be available in near real-time
Title: Re: MOSAiC news
Post by: uniquorn on September 17, 2019, 01:03:29 PM
Mosaic startup area today, worldview aqua modis, small contrast adjustment
Title: Re: MOSAiC news
Post by: blumenkraft on September 20, 2019, 10:27:41 AM
Great podcast with Markus Rex from Alfred-Wegener-Institut about MOSAiC.

So sorry, it's in German.  :-\

Link >>
Title: Re: MOSAiC news
Post by: uniquorn on September 21, 2019, 12:09:54 AM
After a decade of preparations, it’s finally time: this evening at 8:30 p.m. the German icebreaker Polarstern will depart from the Norwegian port of Tromsø. Escorted by the Russian icebreaker Akademik Fedorov, she will set sail for the Central Arctic. On board researchers will investigate a region that is virtually inaccessible in winter, and which is crucial for the global climate. They will gather urgently needed data on the interactions between the atmosphere, ocean and sea ice, as well as on the ecosystem. Thanks to the collaboration between international experts, the one-year-long ice drift past the North Pole will take climate research to a completely new level.
Title: Re: MOSAiC news
Post by: uniquorn on September 22, 2019, 08:01:32 PM
During the beginning of PS122 (mosaic) the Russian research icebreaker Akademik Fedorov from the Arctic and Antarctic Research Institute (AARI) will join Polarstern.

The Polarstern’s companion vessel, the Akademik Fedorov has ‘been there, done that’. On 2 August 2007, it reached the North Pole with 100 scientists and researchers and two deep sea mini-submarines where the scientists dove to a depth of more than 13,200 feet (4,000 m) to collect sediment cores.

Some background history while icebreakers are in transit.
An idea to use the drift ice for the exploration of nature in the high latitudes of the Arctic Ocean belongs to Fridtjof Nansen, who fulfilled it on Fram between 1893 and 1896. The first stations to use drift ice as means of scientific exploration of the Arctic originated in the Soviet Union in 1937, when the first such station in the world, North Pole-1, started operations.[1]

North Pole-1 was established on May 21, 1937 some 20 km from the North Pole by the expedition into the high latitudes. Sever-1, led by Otto Schmidt. "NP-1" operated for 9 months, during which the ice floe travelled 2,850 kilometres. On February 19, 1938, Soviet ice breakers Taimyr and Murman took off four polar explorers from the station, who immediately became famous in the USSR and were awarded titles Hero of the Soviet Union: hydrobiologist Pyotr Shirshov, geophysicist Yevgeny Fyodorov, radioman Ernst Krenkel and their leader Ivan Papanin.

Since 1954 Soviet "NP" stations worked continuously, with one to three such stations operating simultaneously each year. The total distance drifted between 1937 and 1973 was over 80,000 kilometres. North Pole-22 is particularly notable for its record drift, lasting nine years. On June 28, 1972 the ice floe with North Pole-19 passed over the North Pole for the first time ever.

During such long-term observations by "NP" stations, a lot of important discoveries in physical geography were made, valuable conclusions on regularities and the connection between processes in the polar region of the Earth's hydrosphere and atmosphere were obtained. Some of the most important discoveries were finding the deep-water Lomonosov Ridge,[2] which crosses the Arctic Ocean, other large features of the ocean bottom's relief, the discovery of two systems of the drift (circular and "wash-out"), the fact of cyclones' active penetration into the Central Arctic.

Akademik Fedorov location
Title: Re: MOSAiC news
Post by: uniquorn on September 22, 2019, 08:39:03 PM
Mosaic startup location with Zack Labe's sept1-18 925mb temp anomaly.
Firstly over open water to show ascat features (contrast adjusted), then over land and ice.
The mask was created using middle concentration amsr2-uhh ice.
edit: forgot scale and thanks to A-Team
Title: Re: MOSAiC news
Post by: uniquorn on September 23, 2019, 08:53:41 AM
polarstern location
Title: Re: MOSAiC news
Post by: uniquorn on September 23, 2019, 09:16:11 AM
More background on ice drift expeditions, 2014:

Alone on an Arctic ice floe, with a hovercraft
By Carolyn Gramling Sep. 12, 2014
Somewhere in the Arctic Ocean, two Norwegian scientists are adrift on an ice floe, equipped with a year’s worth of food and fuel—and one research hovercraft named SABVABAA (Inuit for “flows swiftly over it”). University of Bergen/Nansen Environmental and Remote Sensing Center professor emeritus Yngve Kristoffersen, 72, and crew member Audun Tholfsen established ice drift station FRAM-2014/15 on the 1.1-meter-thick floe on 30 August, when it was 280 kilometers from the North Pole. Over the next few months, they will drift northward along the submarine Lomonosov Ridge, taking sediment cores to learn about the polar environment more than 60 million years ago. It’s the hovercraft that makes the setup truly unique: Using SABVABAA, the researchers can travel up to 100 kilometers from their floating base, assessing ice properties, currents, and water temperatures. The hovercraft—the brainchild of Kristoffersen and physicist John Hall, 74, of the Geological Survey of Israel—also makes it possible to conduct a year-round study, Hall says. The ridge is covered by thick multiyear ice, forbidding to icebreakers, but SABVABAA (pictured) “allows you to have boots on the ground.”

Video here:  <>  (remove chevrons)
Title: Re: MOSAiC news
Post by: uniquorn on September 23, 2019, 11:54:17 AM
Possibly the last day for full daylight visual from worldview on the startup sight. Is there any 1.5m thick ice there?
Uni-bremen smos sep22.
Title: Re: MOSAiC news
Post by: uniquorn on September 23, 2019, 07:23:15 PM
The last 7days of the mosaic multisensor map of the startup area (small)
click to run
Title: Re: MOSAiC news
Post by: uniquorn on September 25, 2019, 07:02:01 PM
Following up on ice thickness above, here is ascat, contrast enhanced, overlaid with amsr2-uhh low concentration ice at 80%, with a further overlay of SMOS 50cm thickness or greater outlined in white. The mosaic start up area is indicated in red. sep1-24
amsr2-uhh 100% concentration ice has been set to fully transparent as have all the SMOS thicknesses lower than 50cm
Title: Re: MOSAiC news
Post by: Threebellies on September 25, 2019, 11:16:05 PM
Following up on ice thickness above, here is ascat, contrast enhanced, overlaid with amsr2-uhh low concentration ice at 80%, with a further overlay of SMOS 50cm thickness or greater outlined in white. The mosaic start up area is indicated in red. sep1-24
amsr2-uhh 100% concentration ice has been set to fully transparent as have all the SMOS thicknesses lower than 50cm

Amazing image! Makes the CAB look like a breeding ground for ice to get just thick enough to where it feeds the ice (perhaps?) still subject to “melting conditions” in the peripheral seas. That really tells a nice overall tale of the importance of the Arctic Summer (>85N perhaps) and also it’s “winter”. It seems like it and perhaps the Greenland sea will be some of the holdout places perhaps as Arctic sea ice extent (ASI) continues its death spiral overall.
Title: Re: MOSAiC news
Post by: uniquorn on September 26, 2019, 12:38:12 PM
It may still be a little early to use SMOS as a reliable indicator of thickness. Interference around the 'pole hole' should probably be largely ignored. Also note that the SMOS 50cm thickness contour follows some of the weather 'interference' shown by ascat, which is too fast to be related to a thickness change.

The thickness of thin sea ice (SIT) is daily retrieved from observations of the L-band microwave sensor SMOS (Soil Moisture and Ocean Salinity). Horizontal and vertical polarized brightness temperatures in the incidence angle range of 40° to 50° are averaged. The ice thickness is then inferred from the polarization difference and the intensity using an empirical method (Huntemann et al., 2014).

Thin sea ice occurs during the freezing season. In the melting season, the thickness of sea ice is highly variable and the emission properties in the microwave change due to the wetness of the surface and occurrence of melt ponds in the Arctic. Therefore, thickness data are calculated only during the freezing season, that is from October to April in the Arctic and from March to September in the Antarctic. During the melting season, the procedure does not yield meaningful results.

As the resolution of SMOS at the used incidence angle range is about 40 km, only larger regions of thin ice will be retrieved correctly. The rim of thin ice shown in many cases not necessarily indicates thin ice, but can also be caused by the smearing effect (convolution) of the low resolution.

Each day of ice thickness data product are calculated twice to ensure that all swath files were available in the archived product. First processing is done directly on the next day with only about 7 hours delay. At this time it can happen that not all swath files are available and another processing of the same day is initiated 23 hours later. In more than 50% of the time the first processing does not include all swath but usually provides sufficient coverage for Arctic and Antarctic regions.

This service has been developed in the framework of the EU project SIDARUS. After completion of the SIDARUS project end 2013, the service is continued on a best effort base in the context of the Polar View and of the Arctic Regional Ocean Observing System (Arctic ROOS).
The ice edge is likely to move south slowly this year until SST's are lower. It will be interesting to see some 'on the ice' measurements from mosaic when they find a thick enough floe to moor to.
Title: Re: MOSAiC news
Post by: blumenkraft on September 26, 2019, 05:22:05 PM
Almost there! \o/
Title: Re: MOSAiC news
Post by: blumenkraft on September 26, 2019, 10:57:34 PM
The first seven days. (slow playing GIF so you can read :) )
Title: Re: MOSAiC news
Post by: helorime on September 27, 2019, 05:03:42 AM
Just a news story.
Title: Re: MOSAiC news
Post by: uniquorn on September 27, 2019, 01:52:17 PM
A closer look at polarstern's locations sep26-27 and this quote from the itinerary
As part of the journey the four moorings of Vera Schlindwein (DE.AWI) that are located in the area 82°N and 119°E will need to be collected

Hopefully they are successful in locating and collecting the four Gakkel Ridge micro-seismic moorings. A previous paper by Vera Schlindwein here
The active mid-ocean ridge of the Arctic Ocean, named Gakkel ridge, is the slowest spreading ridge of the global system of mid-oceanic ridges with full spreading rates declining from about 12.5 to 6 mm yr-1 from west to east. Geological models of seafloor spreading predict a decreasing intensity of magmatic processes with decreasing spreading rate. In summer 2001, the multidisciplinary Arctic Mid-Ocean Ridge Expedition (AMORE2001) discovered robust magmatism at western Gakkel ridge, an amagmatic section further east and pronounced volcanic centres at eastern Gakkel ridge.
edit: updated, join the dots
Title: Re: MOSAiC news
Post by: uniquorn on September 27, 2019, 06:13:08 PM
AMSR2 concentration is a great product but doesn't scale well to Sentinel1 resolution. Meereisportal are now providing a version of the multisensor map without the overlay (

sep25-26, small.
It's a real bonus from this expedition already that we can now see clear daily Sentinel1 coverage of this area.
Title: Re: MOSAiC news
Post by: uniquorn on September 27, 2019, 09:31:33 PM
What a difference a day makes. A small crop of the mosaic multisensor high res map showing compaction and refreeze in the startup area, sep19-26
Title: Re: MOSAiC news
Post by: blumenkraft on September 28, 2019, 10:18:02 AM
--- NEWS ---
Title: Re: MOSAiC news
Post by: uniquorn on September 28, 2019, 01:25:49 PM
gmrt bathymetry with rough sailwx PS location overlay

edit: better overlay
Title: Re: MOSAiC news
Post by: blumenkraft on September 29, 2019, 09:53:01 AM
--- NEWS ---
Title: Re: MOSAiC news
Post by: uniquorn on September 29, 2019, 04:18:45 PM
Polarstern in the startup area, maybe taking a look at the darker floe due north. It looks like the only candidate at the moment on the multisensor no overlay map (
Hopefully they will reduce the triangle size at some point or make it semi transparent.
Title: Re: MOSAiC news
Post by: uniquorn on September 29, 2019, 04:52:41 PM
nullschool temp=-11.9C, PStemp=-7.6C @1400
windy has ecmwf= -7C and gfs= -12C @1400
Are there any volunteers for documenting actual temps vs model temps during the mosaic expedition? Polarstern data is here (
Title: Re: MOSAiC news
Post by: Jim Hunt on September 29, 2019, 09:02:13 PM
Are there any volunteers for documenting actual temps

I'm afraid I'm anxiously awaiting IMB buoy deployment.
Title: Re: MOSAiC news
Post by: blumenkraft on September 29, 2019, 09:09:17 PM

(goddamit are we nerds... ;D )
Title: Re: MOSAiC news
Post by: uniquorn on September 30, 2019, 10:22:23 AM
The team of #MOSAiCexpedition takes first steps on the sea ice. They left #Polarstern to deploy a buoy which will provide them data about drift and meteorological conditions. You can
follow the buoy at

Meerisportal links to where there are 2 new buoys reporting from day 272 with rather conflicting data (Ts=surface temperature, Ta=atmospheric temperature)
Note that "Surface Temperature (Ts)" is measured from the bottom of the buoy hull. If the buoy is floating, then the reported temperature is of the sea surface. If the buoy is frozen into the ice, or sitting on top of it, then the reported temperature is of the ground or ice. The freezing temperature of sea water is about -1.8C, so temperature readings below this indicate ground or ice temperatures.
Hopefully they will provide a link to more data on their own site at some point

edit:polarstern hasn't been that far north yet
Akademik Fedorov doesn't report location to sailwx.
edit2: More new buoy data further down the list (-999 means no report)
Title: Re: MOSAiC news
Post by: sailor on September 30, 2019, 06:00:08 PM
That's already 30 to 50 centimeters of snow from that picture
Title: Re: MOSAiC news
Post by: uniquorn on September 30, 2019, 06:28:17 PM
Yes, looks like it, though no coordinates for where it was taken. N84 58 E136 5
Title: Re: MOSAiC news
Post by: uniquorn on September 30, 2019, 07:21:27 PM
Possible site may be hidden by location marker but the previous two day's high res images give a good view of the area. sailwx coords N 85°06' E 137°18' (allow for some drift since the last image)
It's a shame there is no ship's radar yet.
Title: Re: MOSAiC news
Post by: uniquorn on October 01, 2019, 11:46:50 AM
Spot the boat.
Polarstern position 2019-Sep-30 04:00   N 85°06' E 137°48'
Polarview, 20190930T044920, slight contrast adjustment. Click for full resolution.
Title: Re: MOSAiC news
Post by: uniquorn on October 01, 2019, 12:16:49 PM
Polarview 16bit jp2 of yesterday's red triangle area with heavy contrast (saved as jpeg)
Title: Re: MOSAiC news
Post by: blumenkraft on October 01, 2019, 12:30:09 PM
Yep, that's the Polarstern. :D

Great find, Uniquorn! \o/
Title: Re: MOSAiC news
Post by: uniquorn on October 01, 2019, 02:32:05 PM
Mosaic buoy data looking tidier today on :)
85.76N must be Akademik Fedorov. PS top left, AF bottom right. Click for full resolution as the thumbnail doesn't really show them. (adaptive contrast applied)

Reassessing that snow depth upthread to ~15cm ?
Title: Re: MOSAiC news
Post by: blumenkraft on October 01, 2019, 02:49:47 PM
Oh, is the Polarstern bigger than the Akademik Fedorov?
Title: Re: MOSAiC news
Post by: uniquorn on October 01, 2019, 03:33:08 PM
PS: Length 117.9 m; beam 25 m; draft 10.7 m.
AF: Length 141 m; beam 17 m.
according to sailwx
maybe it's stealthier ;)
Title: Re: MOSAiC news
Post by: blumenkraft on October 01, 2019, 03:56:19 PM
That must be it! ;)
Title: Re: MOSAiC news
Post by: uniquorn on October 01, 2019, 05:47:23 PM
FRAM workshop nov2018. Everyone is doing their best. More data will turn up eventually :)
Task 3.1   Short- and midterm Activities and Goals 19/20/21:
•Better implement ROV data flow!
Buoy data flow needs to be improved (MOSAiC!)    Current progress too slow. Needs additional manpower! 
•Concept for data costs! This is expensive for the sections!
•Personnel: Christian is in Canada until mid 2019, then contract runs out. Mario is 50% FRAM until mid 2019.
•Continuation as LKII: 520+260 kEUR, 3+2 FTE, Arc+Ant
•Manage SPOT & MOSAiC
•Continue developments, transfer all knowledge to AWI
My bold :)
edit:a daily copy into /maps/latest/ would do me
Title: Re: MOSAiC news
Post by: blumenkraft on October 02, 2019, 09:36:11 AM
--- NEWS ---
Title: Re: MOSAiC news
Post by: blumenkraft on October 02, 2019, 07:15:57 PM
Slideshow with the latest images.
Title: Re: MOSAiC news
Post by: ghoti on October 02, 2019, 07:37:37 PM
This search for a suitable floe is ongoing

This has become a common problem for placing instruments on the Arctic ice. It also means measurements are being done under unrepresentative conditions.

Using sampling to ultimately estimate the conditions of the entire Arctic via statistical analysis requires representative (usually random) sampling but this is no longer possible. The result is likely over estimation of sea ice thickness and stability.
Title: Re: MOSAiC news
Post by: A-Team on October 03, 2019, 12:06:18 AM
Mosaic is a fantastic endeavor that will provide a massive amount of observational data via an incredible array of modern instrumentation (relative to the last go-round, SHEBA, of 1999). Results will dominate the scientific literature on the Arctic Ocean for years to come because the interior basin has heretofore largely gone un-instrumented.

Mosaic will greatly improve the interpretability of satellite imagery and provide a reality check on model predictions never regularly confronted with observation. Just having real weather assimilated into daily ECMWF initializations is a huge step forward over meagre shoreline inputs, for example measured 2m winds responsible for icepack motion and export.

Ice-atmosphere couplings (eg radiative balance, boundary layer turbulent flux, cloud properties) depend on location and weather, not on the floe selected. While the Polarstern provides the center of observation, the secondary deployments go out a radius of 40 km. With drift, this generate a swath of measurements nearly a degree of latitude wide (111 km) wide, rather than point data (mooring) or line data (buoy).

The second study component is the ice itself. It has not yet proved possible to determine ice mass balance issues (thickness, bottom growth, melt ponds) year-round with any accuracy from remote sensing, much less modeling, so the comprehensive thicknesses will be a real breath of fresh air.

The third focus is water column under the ice. The anticipated drift across the Eurasian Basin does not seem ideal for the study of encroaching Atlantification (like N-ICE2015 or the PS's recent visit to the upper Fram), though the northern Laptev is an area of very active concern for mixing of thermal and saline stratifications.

It's never been clear what provides the vast volumes of return water to the East Greenland Current because the Waddell Sea and points north have been under thick ice for ages. Mosaic has an acoustic tomography experiment going relative to new moorings that can address this.

Mosaic planners knew from the outset that finding a suitable floe would be mission-critical. They allocated a full week for that search; as I write, the ship has been at N 85°12' E 134°18' for eight hours. They are looking for 1.2 m or thicker ice, a port-side mooring for logistics, and a large enough floe so that electricity and LAN data lines can reach remote instrumentation.

The safety issues involve pressure ridges heaving experimental set-ups, leads opening suddenly, nearby floes over-rafting, patches of very thin ice, strong swells from remote storms, aggressive penguins walruses and bears, plus working long hours in cold, dark and possibly very windy conditions. (The PS serves alcohol at two on-board bars.)

I am skeptical -- based on the multi-satellite September time series below -- that they will find the perfect floe at 85ºN because the Laptev is in such poor condition but if they go much farther towards the Pole, there may not be notable net drift towards the Fram.

The gif below shows Osisaf, Ascat and Smos embedded within a novel differential AMSR2. The complex palette is provided in the lower left corner. The Polarstern search wedge, called a spherical rectangle or section double frustrum, is shown as an overlay (map adornment) for each satellite. The base resolution is 6.25 km/pxl for AMSR2 unchanged from archive.

With so much data coming in so many forms, synchronized integration becomes increasingly important in science-retaining visualizations. While this one was easy enough to make, it doesn't roll forward because of the differencing wrt a fixed final day, 30 Sep 19.
Title: Re: MOSAiC news
Post by: oren on October 03, 2019, 02:45:45 AM
Hello A-Team! Your posts are always welcome. Astounding visualization.

I was wondering if Mosaic might make their thickness measurements available. I am more interested in the many floes they skip, rather than the one floe they finally select (if they even manage to find a suitable one). I see this a a very rare opportunity to compare direct local measurements to SMOS remote sensing and to PIOMAS modelling.
Title: Re: MOSAiC news
Post by: uniquorn on October 03, 2019, 08:31:57 PM
That pallette highlights another fracture along the Lomonosov ridge from sep24-26 which I hadn't noticed before. These are not frequent, but not uncommon either. It's possible that they'll be drifting in that direction.

update on PS location and temps, looks like more buoys, 29 currently on the iabp table
Title: Re: MOSAiC news
Post by: uniquorn on October 03, 2019, 09:53:26 PM
By the way, does anyone recognise this buoy from the mosaic image upthread?
Title: Re: MOSAiC news
Post by: A-Team on October 04, 2019, 03:47:42 AM
Not real helpful to tweet a buoy picture without furnishing its identifying number and capabilities.

Here is a very nice site hosting SIMB3 buoy data. The founding engineers were graduate students with Don Perovich at Dartmouth so it is safe to assume robust design standards were used in manufacturing these buoys. The Polarstern has not yet deployed its four. There is one just launched in the Beaufort (IMEI: 386840), that is showing just 90 cm of ice well in from the periphery. The first figure shows condensed hightlights of this site. Hopefully someone here can explore the embedded graphics option that they offer.

The Polarstern is carrying 14 other buoys with tracking csvl provided by APL at UW. These are active but have not yet gathered much data.

@Zlabe has some great new summary graphics for the Arctic which I combined with an Ascat and Polerstern location wedge.. These show that the air and water are anomalously warm for September.

A good way to keep current: set up your web browser to open a tab set for this list of links: (has not resumed as of Oct 3d, still on 31 July 2019)  (has not resumed as of Oct 3d, still on 31 July 2019) hourly coordinates for Polarstern
Title: Re: MOSAiC news
Post by: A-Team on October 04, 2019, 04:00:09 AM
Here is that active SIMB3 buoy in the Beaufort. It is not exactly part of the Mosaic expedition though it seems Perovich is sailing steaming dieseling on the Polarstern. As noted, the ice plus snow is not yet a meter thick. meaning the ice alone is thinner still.

Buoy data are better plotted in polar stereographic than mercator-like projections. The meridian is very easy to find using AMSR2 UHH because it has a 1º longitude graticule on its outside, easily exposed by picking land-red and deleting to alpha in a blank floating layer.

To intersect with the latitude, the base map has a scale of 839 pixels out to 75º which pencils out to 59.33 pixels per degree. So just multiple by buoy latitude and draw a circle out that many pixels, fill the boundary. Then place the star on the actual AMSR2 layer according to the floating layer.

Oren: wondering if Mosaic might make their thickness measurements available. I am more interested in the many floes they skip, rather than the one floe they finally select
I had that same question because we have long been starved for real ice thicknesses. I wrote the help desk but the 'Send' button wasn't operative. Those EMbirds measure distance to the surface and distance to the saltwater very accurately and with excellent horizontal resolution. On N-ICE2015, they timed the flights to coincide with the satellite overpass and spot surface drilling.

They may not retain the data after rejecting the floe, not feel it is properly  calibrated, or not have the bandwidth to send it ashore. Iridium data packets from buoys are a few hundred bytes (if you can remember what those were).

On the selected floe, which will likely be a fused composite of floes with different histories, they are planning a comprehensive 4D study of its thickness and freeze thaw cycle from above and below. So hopefully an interactive 3D model like we see for some of the Greenland glaciers.

The PS has still not found its floe but must be in a promising area because they have been lingering along 85º for several days. They haven't missed much TPD; OsiSaf had a couple of days of that but today the ice is back floundering about as it did all summer.

@zlabe attributes this to the persistent negative (N)AO and lack of seasonal polar vortex transition. Useful references as the atmosphere transitions to the NH wintertime circulation:

+[Polar Vortex]
+[Sudden Stratospheric Warming]
+[Quasi-Biennial Oscillation]
+[Atmospheric Coupling]

Can someone here explain what significance the dew point has in these circumstances? Or do they just collect it because that's easier than not collecting it?
Title: Re: MOSAiC news
Post by: Jim Hunt on October 04, 2019, 11:36:04 AM
The Polarstern has not yet deployed its four.

I am still anxiously awaiting data from those four. However Polarstern does at least now seem to have found a floe to get frozen in next to:

We finally found the piece of ice that will be the home for Polarstern for the next year. It’s a floe a few kilometers in diameter and with thickness ranging from half a meter to a few meters.

Hopefully someone here can explore the embedded graphics option that they offer.

I'll see what "Snow White" and I can come up with!
Title: Re: MOSAiC news
Post by: uniquorn on October 04, 2019, 12:40:44 PM
A quick look at mosaic aibp buoy locations up to oct4, just lat/lon, no projection.
5 buoys listed are not in this area 84-86N 120-140E
Title: Re: MOSAiC news
Post by: uniquorn on October 04, 2019, 01:13:38 PM
A closer look at 4 of them. Dates A time series will be useful when it's a bit clearer what is happening. Some of this looks like drift, some of it delivery. All the scales are different here to maximise the image size.
edit: slower gif
Title: Re: MOSAiC news
Post by: gerontocrat on October 04, 2019, 02:42:44 PM
Hello A-Team! Your posts are always welcome. Astounding visualization.

I was wondering if Mosaic might make their thickness measurements available. I am more interested in the many floes they skip, rather than the one floe they finally select (if they even manage to find a suitable one). I see this a a very rare opportunity to compare direct local measurements to SMOS remote sensing and to PIOMAS modelling.

I am also wondering if and when IceSat-2 data is going to be part of an integrated data suite.
Laser precision: NASA Flights, satellite align over sea ice
In April, instruments aboard NASA's Operation IceBridge airborne campaign and the Ice, Cloud and Land Elevation Satellite-2 succeeded in measuring the same Arctic sea ice at the same time, a tricky feat given the shifting sea ice. Scientists have now analyzed airborne and spaceborne height measurements, and found that the two datasets match almost exactly, demonstrating how precisely ICESat-2 can measure the heights of the sea ice's bumpy, cracked surface.

Sea ice height profiles from ICESat-2 can tell scientists whether the ice is a newly formed, smooth surface or an older, rougher section. The key measurement from ICESat-2, however, is how high the ice surface is above the open water, called freeboard. If scientists know that number, they can calculate the thickness - which isn't directly measured from satellite data. When Kwok and his colleagues compared freeboard measurements from ICESat-2 and Operation IceBridge's Airborne Topographic Mapper instrument for the April flights, they were within 0.8 to 1.6 inches (2 to 4 centimeters) of each other.

With additional flights over land and sea ice in both Greenland and Antarctica this fall, Operation IceBridge is continuing to help assess ICESat-2 data, along with other efforts including the third year of an Antarctic ground traverse along a section of the 88 degree South line of latitude.
Title: Re: MOSAiC news
Post by: A-Team on October 04, 2019, 03:21:02 PM
Nice spotting, Jim. Now if we only had a list of all urls from the people on board tweeting or posting to home institution blogs, we could keep up a lot better. collects posts from Brookhaven NL and posts some very nice photos. They are going to have a huge problem initially with polar bears because those are highly concentrated near the Laptev sea ice edge where the food is, rather than swimming around in 1000 km patch of open ocean.

Hopefully they can scare the bears off and not shoot them the way drilling projects on Greenland have done. Walrus have been in the news lately too, sinking a Russian zodiac near FJL. The Oden photographed a walrus messing with scientific gear last summer at the North Pole. A walrus thrashed Nansen's kayaks on the return trip. I don't anticipate any problems with penguins.

I have belatedly realized that a changing hourly PS position report from sailwx doesn't mean the ship is underway because sea ice drift is of comparable magnitude to them poking about looking for the perfect floe.

They have fixed the daily ice obliteration on the Sentinel radar; the heavy triangle is gone and replaced by a too-small circle. It's still opaque though. The problem is working with one layer; the red route should be done in a second layer with a transparency slider (a capability offered already in Feb 1990 by Photoshop 1.0).

The reason I bring this up is we need a very clear radar image of the floe in order to match it with Sept 21-24 visible Worldview (the last clear sunlit days) to allow traceback of its origin to early June when Ascat can pick up its motion back to formation in the fall of 2018.

As Uniq noted earlier, this is best done using the unadorned jp2 file served by It sounds though that the floe can still be photographed from above in the visible even though WV's growing pole hole blacked out this latitude and north about ten days ago.

That is, the PS will determine all its current and future properties such as healed leads, pressure ridges, underwater keels, brine pockets, bottom algae, sunlight transparency, snow layers, fire soot etc etc.

My expectation is this floe formed as FYI on the periphery of the ice pack maybe two hundred km north and a bit east of Kotelny Island (NSI). It is not a piece of MYI from the Beaufort arm, nor related to thick ice between the Pole and CAA, nor broken-off landfast Siberian ice. It then drifted over the last 11 months, initially along its parallel (ie zonally) but with an admixture of south meridional this spring, to its current position, graduating to SYI on Sept 15.

Note the primary floe at 3 km diameter is far short of the 30-40 radius necessary for the secondary deployments. The adjacent floes, whose leads are now freezing up, will have a similar provenance. These will thicken but never attain the structural strength of the main floe. Thus the Polarstern is thus moored on a future shear line.

I've attached a bit of Norwegian maritime humor because the main Mosaic planning document shows the PS moored starboard. It is customary for the captain to be given a green and red sock as mnemonic to avoid collisions with other transiting vessels.

Following up on earlier observations of FishooW and Zlabe on the unusually persistent negativity of the North Atlantic Oscillation (NAO) this summer, I graphed the last 12 months of daily readings. The onset in late May coincided very closely with the cessation of Fram/Nares export and TransPolar Drift, per Ascat and OsiSaf. No return to positive winter values is foreseen this month.

TPD drift would be nice but most research programs on the Polarstern don't require it. A lot of this is Nansen nostalgia (or should I say Sverdrup nostalgia as he captained the Fram after Nansen abandoned ship).

The Akademik Fedorov is named after a distinguished early participant Yevgeny Fyodorov (Фёдоров) in the first of many Russian sea ice drift experiments. (These 'don't count' as not conducted by westerners, any more than Alfred Wegener, not an American, counts as the 1912 discoverer of plate tectonics despite a whole book on continental drift.)

Russian scientists landed a plane (no runway) at 89°25′N 78°40′W in May 1937 and drifted 2,850 km over nine months to mid-Greenland where they were miraculously picked off by icebreakers before the floe melted out. (They carried a hand-cranked radio so did not depend on a battery charge lasting.) The PS carries two Piston Bullies to plow airport-smooth runways, along with innumerable creature comforts, yet millennials on board complain every day about perceived hardships.

Some of the AWI documents conflate ice drift on the ocean (entirely wind-driven) with ice floating down a river (eg annual breakup of MacKenzie). Surface currents in the central Arctic Ocean are entirely negligible (discounting keel-induced local advection). AO tides and tidal currents are very minor and also irrelevant.

Think of a dry leaf skittering along the sidewalk. It's the wind that carries the leaf along. The sidewalk itself is not moving. For the Arctic Circumpolar Boundary Current see:
Title: Re: MOSAiC news
Post by: Jim Hunt on October 04, 2019, 03:56:02 PM
The Oden photographed a walrus messing with scientific gear last summer at the North Pole.

In a fortuitous face to face meeting with Helen Czerski at Silverstone earlier this year I asked her how it might have got there.

She said that whilst it wasn't her speciality she believed that in extremis Walrus have been known to eat seals.
Title: Re: MOSAiC news
Post by: blumenkraft on October 04, 2019, 04:12:23 PM
AWI blog post:

A fortress of ice and snow

Link >>
Title: Re: MOSAiC news
Post by: A-Team on October 04, 2019, 04:43:24 PM
Walrus eat all kinds of stuff besides shellfish. Here are some published accounts:

-- 2008 BBC footage of walruses hunting spectacled eiders overwintering in the Bering Sea
-- thick-billed murres taken time and again by walruses off Coats Island in Hudson Bay
-- successful walrus attacks on molting pink-footed geese off  Svalbard
-- walrus catching bearded seals
-- stomach of walrus filled with large pieces of sealskin with the blubber attached,
-- walrus shot with floe seal in its mouth which it had just captured;
-- walrus killing and eating a wounded polar bear
-- group of walruses eating a narwhal
Title: Re: MOSAiC news
Post by: gerontocrat on October 04, 2019, 06:07:18 PM
AWI blog post:

A fortress of ice and snow

Link >>
According to GFS there is a plume of very warm air heading their way from the North Atlantic in around 5 days or so.
Title: Re: MOSAiC news
Post by: be cause on October 04, 2019, 06:42:27 PM
'I hope there will still be a floe for them to attach to come the fall ' .. my thoughts when this expedition was reported in the 'what's new thread back in June . Seems my concerns are being realized . I really wish every success to everyone involved ; in the Arctic , elsewhere and of course here on ASIF .. and it is a joy to once again welcome A-team back among us .

  .. still free b.c.  :)
Title: Re: MOSAiC news
Post by: gerontocrat on October 04, 2019, 07:52:42 PM

  .. still free b.c.  :)
and not on the run from Mr. Plod?
Title: Re: MOSAiC news
Post by: SteveMDFP on October 04, 2019, 08:47:41 PM

  .. still free b.c.  :)

Very happy to hear that!!
Title: Re: MOSAiC news
Post by: ParabolicD on October 04, 2019, 10:36:13 PM
This is currently the top story on the bbc science page. (

Hopefully this means the expedition is going to be broadcast to a wider audience.

Also some good photos of the state of the ice around the ship.
Title: Re: MOSAiC news
Post by: uniquorn on October 04, 2019, 11:12:17 PM
Polarview this morning
Title: Re: MOSAiC news
Post by: A-Team on October 05, 2019, 12:20:37 AM
Some good material on that BBC page above. Some highlights are captured below:

"After a brief but intensive search, we've found our home for the months to come," said expedition leader Prof Markus Rex, from AWI. 

"It may not be the perfect floe but it's the best one in this part of the Arctic and offers better working conditions than we could have expected after a warm Arctic summer."

Sixteen locations were scouted with the aid of satellite imagery and helicopters. A floe measuring 2.5km by 3.5km was eventually chosen.

The ice looks very fractured but that can largely be attributed to two icebreakers coming in. Freeboard looks fairly minimal but that is hard to estimate from oblique photos. The snow depth is again ankle-deep (15cm). That is still enough to insulate the ice somewhat from the cold of the air which has been running -8 to -12ºC in recent hours.

"Snow is an insulator. Its R-value varies depending on moisture content and density of the snow granules; but on average snow has an R-value of 1 per inch — about the same as wood. Twelve inches of snow have roughly the same insulating value as a 2x4 wall filled with fiberglass insulation." [R value is a US spec; I don't know what it corresponds to in Euro-land.)

In theory, there should be a timestamp, GPS location, direction of view, etc in the exif metadata buried in the photo file. However that is routinely scrubbed or altered during production. The online tools below could not find anything of interest. Sept 30th dates are indicated but those might be spurious.

The cost of €130m ($150m) of the enormous MOSAiC scientific mission is fairly modest, very similar to the reported cost of a single RQ-4A Global Hawk BAMS-D surveillance drone like the one Iran downed in June. The US military budget for the 2019 year is $693,058,000,000 or enough for 4620 Arctic Mosaic expeditions.
Title: Re: MOSAiC news
Post by: A-Team on October 05, 2019, 12:56:35 AM
Thanks to Uniq at #74, we can compare the Sentinel-1 images being archived by Mosaic for ice motion to the originals served at (Note #74 includes essential photo ID parameters unlike the Mosaic archive which is blending multiple dates.)

The image below needs a click to display at its 1190 x 584 pixels 'native' resolution. The Mosaic image had to be enlarged 300% to more or less match features which pixelated them terribly.

I found the blue ice motion arrows to be way off the mark both in direction and speed in comparing 3-4 Oct; they may just be dumbed down OsiSaf which span 48 hours and are not nearly of the needed resolution. Overall ice pack motion is better followed in Ascat from late Sept to early June.

Mosaic may just have made a temporary archive merely for floe-finding; hopefully they will settle in soon to better characterization of drift (for which they plan a large array of GPS units that also measure local pack deformation). There are quite a few compressible spaces now not fully frozen over, yet the motion in a 1º x 1º rectangle about the ship is mostly cohesive (uneven wind stress? weaker ice to the south?).

Sailwx only reports PS position to one decimal degree (~11km) and does not provide stern-to-bow azimuths needed for tracking ship+floe rotation. The PS knows very accurately where it is located and pointed but so far we don't where/if that data is being shared in nrt. However sailwx is hourly whereas S1AB has at best twice daily temporal resolution.

It's easier to track floe motion in the visible though WorldView has gone dark and will stay dark into March. However for provenance of the selected floe, summer dates are needed. Taking some cloud-free days, it proves feasible to match up Terra to S1 features -- which appear very different at different wavelengths. If the ice hasn't moved too much, it should still be possible to find the selected floe in visible. Needs click to enlarge.
Title: Re: MOSAiC news
Post by: A-Team on October 05, 2019, 02:10:48 PM
Take an inside tour of the Polarstern?

"During the historic meeting of USCGC Healy and Germany's RV Polarstern at the North Pole on 07 Sept 2015 we had the opportunity to exchange visits.  Both ships were conducting Arctic GEOTRACES cruises."

Goddard Institute assembled the last cloud-free visible satellite mosaic of the Arctic Ocean over Sept 17-23. The PS is shown by a red dot at its selected floe on 01 Oct 19.

“We’ll have to wait and see if it’s also stable enough to withstand the autumnal storms that are now brewing,” PI Markus Rex said, adding that the team is “prepared for all scenarios.”

Right. The ice in the northern Laptev has not really set up yet. They have made the best possible decision under the circumstances. A lot of laboriously deployed instrumentation and infrastructure would have to be pulled back on board in the event of swells, flooding of the floe, ridging or shearing.

I worked out the scale on the Polarview imagery Uniq posted in #74 using the distance between 85º-86º as 111.67 km in WGS84 ellipsoid which all GPS devices reference. From the approximate dimension of the selected floe 3.5 x 2.5 km, it is possible to identify the object as a dark oval on S1 radar.

When the next image surfaces on Polarview, we can use the pair to compute real non-gridded velocities because the PV file name provides the UTC time the image was taken to the second.
Title: Re: MOSAiC news
Post by: uniquorn on October 05, 2019, 02:24:32 PM
Here looking at freezing indicated in the Laptev further south by both uni-hamburg amsr2 and uni-bremen SMOS with Mosaic buoy iabp300234068312210. The labels are temperature and day number with hour. Rough location is ringed just on the edge of worldview terra modis visible today.
buoy type is SVP=surface velocity profiler
Title: Re: MOSAiC news
Post by: A-Team on October 05, 2019, 10:05:14 PM
Right, the big issue now is how fast the Polarstern's safety zone will grow to the south (towards New Siberian Islands). A buffer for long reach swells would really improve their situation, as would solidified adjacent ice.

Sept 2019 is an especially unfavorable for late open water/slush in the northern Laptev mooring area as the PS team is well aware (3rd and 4th graphics). The latter appends Oct 2018, though that scarcely provides a prediction for this autumn.

I found some trackable features for Oct 04 back to Sep 21 enveloping the Chosen Floe (which itself is not so trackable) and was able to follow them back into Modis/Worldview daylight. The ice has been going around in an aimless circles with no sign of TransPolar Drift onset. Despite leads opening and closing, this region of ice has been moving mostly like a rigid block.

Last May, we found the best way to quantify deformation was via Delaunay triangulation. That is, if three features form a triangle, its changing lengths and angles -- whose values ImageJ conveniently tabulates in CSV -- describe ice deformation since triangles unlike quadrilaterals etc are rigid. This method was used in a recent N-ICE2015 article for the same purpose.

Sentinel-1 does not fly over every day by any means. They seem to be using other sources of imagery in a mix-and-match manner. For example, Sept 25th is a just an exact copy of Sept 26th in the region shown.

The satellite usage table below from Mosaic's main planning document shows the options (needs a click to be readable; color legend is screwed up). Naturally, they have a budge gto buy commercial coverage as needed.
Title: Re: MOSAiC news
Post by: Jim Hunt on October 06, 2019, 12:28:48 AM
Only marginally off topic, after successfully surfing the meat of ex Hurricane Lorenzo's swell at Bude, North Cornwall this morning I wandered into the middle of an art installation:

Perhaps Neo is scanning the horizon for hungry walrus?
Title: Re: MOSAiC news
Post by: Jim Hunt on October 06, 2019, 12:39:44 AM
Meanwhile here's a very crude initial version of the GWC winter 2019/20 Ice Mass Balance buoy page:

Now including MOSAiC IMB buoy #1:
Title: Re: MOSAiC news
Post by: uniquorn on October 06, 2019, 01:29:50 PM
Polarview this morning. PS and AF quite close to each other.
Title: Re: MOSAiC news
Post by: A-Team on October 06, 2019, 02:24:20 PM
Below are some floe tracking images that tie precise lat/lon positions into the WorldView visible dates when floes are more intuitively portrayed in clear weather. The first provides 16 days of daily displacements of the PS Floe based on their archived mix of radar images. Based on a fairly strong anticyclonic OsiSaf today, I expect Floe movement to the 'right' overnight.

The Floe is embedded in a larger context that moves as a semi-rigid block; indeed the whole ice pack is still exhibiting coherence but daily morphological plasticity as can be seen in the translucent greenish animation from earlier in Sept. (Ascat arrives as grayscale but two other channels for color can be made from fourier bandpass filtering that emphasize different scales of contrast variability.)

Sentinel imagery that Uniq has been posting is far higher quality but involves handling large initial files in unpopular jp2 format. The 16bit depth provides much more latitude in contrast adjustment though the gains are not as phenomenal as with 8bit Ascat. At the end of the day, everything has to be posted in 8bit x 3.

In the file names, 20191004T064336 parses out to 2019 Oct 04 at UTC time 06:43.36. The two images are then 06:27 - 06:43 apart or 16 minutes short of 48 hours, critical to accurate measurement of floe motion. It's possible to make 'interferometric' color images from just two frames in ImageJ; these have excellent prospects for displaying deformation over the whole region. As always we are very dependent on satellite providers for spot-on pixel geo-registration.


The dark blob in the center corresponds to the ice oddity in the first image of #77. It has stood out for since last autumn out as a relatively white region in plain Ascat; it is one of the last regions of thick MYI; it barely experienced TPD last winter.

The third image illustrates tracking of an unrelated floe in Modis Terra. Note daily or better coverage is needed to define motion as the 'shortcut' shown does not capture details of multi-day motion.

The fourth image shows the all-weather forward view from the bridge. The dark triangle is aft. While the floe shapes seems terribly distorted, publications have used it in the past to measure floe jostling and ice deformation. This clip is from an earlier voyage. The PS may have it turned on while moored but is not uploading it to a public archive as far as I know. ship radar N-ICE2015
Title: Re: MOSAiC news
Post by: uniquorn on October 06, 2019, 03:14:09 PM
I made some headway with buoy tracking. This visualisation may be useful. Still no projection, just lat/lon. iabp buoy type is IT=Ice tracker, maybe it is on a snowmobile/helicopter?
edit: 36km in 30min, according to the NOAA calculator, maybe helicopter.
Title: Re: MOSAiC news
Post by: uniquorn on October 06, 2019, 06:18:28 PM
The mosaic multisensor map is improving all the time, from large opaque pointer and path to semi transparent for both. :) sep28-0ct5 crop. Maybe it will go to higher resolution as the movement slows down.
I'm not able to match the buoy path above with PS movement so far. Maybe helicopter flying between boats?? I realise the buoy map needs to be inverted and flipped.

edit:added latest polarview sentinel1 jpeg with graticule, showing the position of both boats. Mosaic insert top left
Title: Re: MOSAiC news
Post by: uniquorn on October 06, 2019, 08:12:27 PM
I thought it was accurate buoy placement, but I think sailwx latitude chart resolution is struggling this far north. Probably not much value in posting further.
edit: apologies to the chart creator, the saliwx lat/lon data is only 1 decimal place.

Off the map for ecmwf windy also. ~50km windswesterlies forecast further south on tues.
edit:added the drift path for whoi itp116 close the the pole which is stubbornly refusing fram export at the moment. (grey arrows are the annual drift track)
Title: Re: MOSAiC news
Post by: A-Team on October 07, 2019, 12:06:23 PM
Smos/Smap has fired up its daily archive at U Bremen again as of Oct 4th, having ceased production on July 31. This provides an improved thin ice prediction map relative to plain vanilla Smos (which archives all year despite accuracy deterioration in summer) by using complementary input from a second satellite instrument.These are both passive microwave sensors that provide brightness temperatures at 1.4 GHz. Feb 2019 free full Smos/Smap Apr 2018 free full Schmidt Kaleschke Nnov 2018 tech spec Schmidt Kaleschke

Smos/Smap runs two days behind rather than one day late like Ascat, Smos, OsiSaf, Amsr2 etc. The cut-off is 0.5 m; all ice thicker than that is shown in the same palette color (even though some value remains in the 0.5 to 1.0 m range).

Thus it is most useful right now for Mosaic, near the ice edge during freeze-up.

The 'pole hole' is larger for Smos/Smap (out to 87º) than for Smos. That's just as well because that of Smos is almost always ringed with artifacts. Both use the same thickness palette. Ground resolution is not great but the png's are released at a much more generous size (1173 x 2170 pxl) than Smos (624 x 757 pxl).

It is generally better for enlargements to be done in-house from the raw numerical data than done later from postage-stamp products. For example, the data-obliterating graticule need not be so badly dithered in. Note though that some netCDF tools like Panoply use linear interpolation whereas bicubic probably gives better results.

The first image below shows the two are nearly identical on Oct 5th. This means that Smos was likely quite accurate earlier in Sept contrary to popular opinion.

In terms of the Polarstern, the <0.5m thin ice of the Laptev anomaly starts just to their south. This doesn't have the resolution to speak to individual floes that might be thicker (or practically open water).

The Sep-Oct time series of Smos shows thickening is preceding quite slowly, with thin ice not clearing the pole hole at 87.5º until Sept 22nd. The Polarstern is parked at 85º. This means a lot of ice between the ship and Pole is still quite thin, well less than a meter.

Since one degree of latitude is 111 km, the PS is currently some 555 km south of the pole. The Great Laptev Bight of thin ice reaches up another 555 km from the south. Above Banks Island in the Beaufort, the ice has thickened beyond 0.5m for 1839 km. More typically, thicker ice extends out 1100 km from the pole, the FJI-SV line being another exception like the Laptev. These asymmetries probably reflect the location of the cold pole vs direction of proceeding Atlantification.

Measuring the distances ccw from pole to Smos/Smap thin ice edge on 05 Oct 19 using the 15º graticule, the average distance pencils out to 881 km. Adding up the areas of all the triangle by side-angle-side method using sin(15º) = 0.259 for included pole angle between sectors gives 5,633,429 sq km.

The velocities at which these are expanding would give some idea of when the deployed Polarstern experiments gain a margin of safety; see #79.

lon   pxl   km          lon   pxl   km
  0   266   1107        180   291   1212
 15   209    870        195   260   1083
 30   210    876        210   267   1113
 45   196    816        225   389   1620
 60   172    717        240   347   1446
 75   183    762        255   257   1071
 90   192    801        270   193    804
105   173    720        285   171    711
120   160    666        300   211    879
135   137    570        315   178    741
150   145    603        330   137    570
165   149    621        345   186    774

229   441   1839 farthest ice edge in Beaufort

mage archives:
Title: Re: MOSAiC news
Post by: Jim Hunt on October 07, 2019, 12:35:12 PM
Hot off the MOSAiC news feed:

On Friday evening at 9:30 p.m. boat time the team of MOSAiC Expedition reached their destination: the floe which had been chosen some days before.
Title: Re: MOSAiC news
Post by: uniquorn on October 07, 2019, 04:17:41 PM
polarstern temperatures
Title: Re: MOSAiC news
Post by: RoxTheGeologist on October 07, 2019, 06:24:10 PM

I find the water temp line very satisfying for some reason. It's good to know the universe is working as intended.

Thank you A-Team and Uniquorn. It's going to be a very exciting winter for all scientists, including those of us firmly seated in our armchairs.

Title: Re: MOSAiC news
Post by: A-Team on October 07, 2019, 10:19:20 PM
Safety is a huge issue: a lot of things can go wrong with so many people deploying so many experiments over a remote and harsh location during the course of a year. Incredible preparations were required of all who wished to come aboard, including photojournalists.

Ship & lines please. There are four lifeboats, emergency rafts and a small launch on the ship, lowered by lines not ropes. When Captain Schwarze says jump, you jump (even if it's just off the sofa at your WeWork). Or spend the rest of the cruise cleaning up engine room grease (1st figure, upper right).

Polar bears: German army soldier. Night vision googles. Remote guard tower. Trip line perimeter. Infrared-triggered game cameras. Blasts from ship's horn. Flares. Pepper spray. Rifle as last resort. 

On Svalbard, the most common rifle carried is a Mauser 30-06. It has a confusing 3-way safety with middle position only causing the shell to be ejected, not fired. That lead to a recent death in a scout camp. A Sabatti 308 or H&K G3 is more probable here. PBs bury themselves in snow drifts (eg lee side of pressure ridge) leaving only eyes and nose exposed, then snooze until they can ambush a passerby (as with that young woman in Sv).

The captain has a plan for everything, from fires aboard to abandon ship. The first high risk period is right now, with the ice too thin and the ice margin too close. The second is mid-winter when the ice is too thick for support icebreakers to reach them and at problematic range for helicopters. Fires are a serious risk througout the cruise.

That recent dive boat accident in California ‘raised awareness’ of the risks of lithium battery re-charge fires. Passengers had left them charging overnight by the thousands after the final night dive. I reckon the Polarstern has thousands of electronic devices aboard, plus all the electrical gear the ship would normally carry. Almost all ship fires are wiring, engine room or galley; lithium is new.

We are going to understand the Arctic system a whole lot better thanks to this fabulous effort. It’s not going to stop the sea ice — and everything contingent on it — from falling off a cliff the next few years, any more than posting another expository post here.

What is the shelf life of 2019-20 research, given the rapidity of change? They are building the Polarstern II as we speak.

The animation below runs up to Oct 6th. Although passing weather artifacts cannot be fully removed early on. it clearly shows the ice has not yet settled down in the area they needed to be in for a year's drift. They knew this going in but there were no better options.
Title: Re: MOSAiC news
Post by: Niall Dollard on October 08, 2019, 12:43:55 AM
GFS forecast (from Nullschool) shows a yo-yo swing in temperature in the vicinity of Polarstern over the next 24 hours or so.

By 12 UTC on 8th Oct, a plume of mild arrives up from Svalbard, yielding temperatures slightly above 0 C but it is short lived and 12 hours later at 00 UTC on 9th Oct, it forecasts temperatures below -10 C as cold air is advected across the Pole from the American side towards Russia.
Title: Re: MOSAiC news
Post by: uniquorn on October 08, 2019, 01:13:50 PM
Excellent! Today's mosiaic multisensor map zooms in on the selected floe :) (click for full resolution)
Here is an updated overview of mosaic buoy locations/movement up to oct7, 81-87N 114-140E
Title: Re: MOSAiC news
Post by: A-Team on October 08, 2019, 03:36:41 PM
The Polarstern is 'out of the woods' in terms of AMSR2_large sea ice concentration having solidified in their immediate vicinity to 100% yet the sea ice is still quite dodgy to their south and the ice edge with open water is not notably progressing south in the Laptev. The Polarstern is 142 nm (265 km) north of the nearest open water which surprisingly is still within the reach of long-reach swells. The water there is still too warm, anomalously so.

Although large format time series (3.215 km resolution) are inconvenient to work with, they are well-suited to other tasks such as following the formation of land-fast ice which was once extensive, very thick and perennial but now almost entirely seasonal.

We may think of ice formation in autumn as a phase change from liquid to solid but it is better considered as epitaxial crystal growth in a variably inhomogeneous medium (water + brine + algae). That is, new ice only forms on the bottom and laterally on the sides of existing older ice.

You will never see a block of new surface ice forming ab initio in Arctic Ocean open water with AMSR2. (Preconditioned sub-surface, yes, as in fast outreach coming on now in the Beaufort.) There is too much wind mixing, whereas on the bottom or sides of existing ice there is minimal stirring plus a locally colder mileau -- the preexisting seed ice wouldn't be there otherwise.

This is doubly true for internal regions of sub-100% concentration. Thus color-picking open water invariably yields a plain if wavy ice edge line rather than a topologically more complex boundary. (We did find an exception a couple years back of a stable, inexplicable internal polynya.)

The second time series shows the whole Arctic Ocean for the first week of October. The ice pack as a whole has some internal regions that have not settled down. It rocks forward and back; the split palette shows an equalization over the original AMSR2.

For Polarstern protection from ice-rubbishing swells, faster peripheral pack growth to the south is needed. But is it on the horizon? The blue line (Oct 7th) in the animation doesn't show consistent  progression over the last three weeks. Mosaic may be documenting the first season of a newer New Arctic.
Title: Re: MOSAiC news
Post by: blumenkraft on October 08, 2019, 06:35:59 PM
awww <3
Title: Re: MOSAiC news
Post by: uniquorn on October 08, 2019, 10:39:47 PM
Well fed bears :)
Following on from A-team's post, polarstern is also slowly drifting south at the moment which doesn't help their situation. Here is polarview's latest jp2 combined with the jpg which has the graticule overlay. Akademik Fedorov is brighter today further north. (click for full resolution)

The animation below is ice tracker buoy 300234068129990 showing the last 2 days drift roughly 2 degrees west of mosaic. North is up, west is left (does my head in). Temperatures aren't provided on the IT buoy.
Title: Re: MOSAiC news
Post by: uniquorn on October 09, 2019, 02:23:18 PM
Thinking about the persistent dip in the ice edge in the Laptev, here is amsr2-uhh, mosaic startup area overlaid onto gmrt bathymetry at 60% transparent, sep1-oct8
edit: moved the focus further south
Title: Re: MOSAiC news
Post by: A-Team on October 09, 2019, 09:55:19 PM
Polarstern drifting south and east
The ice shows no sign of getting its drift act together. Some of these autumn freeze season time series could be confused with spring melt season. Either way, great that the PS is out there observing it all.
Title: Re: MOSAiC news
Post by: A-Team on October 09, 2019, 10:29:00 PM
It's not entirely clear that melt season is over in some parts of the Arctic Ocean. The Polarstern is at 85ºN so quite a ways poleward (and west) of the scene below which straddles 80ºN. Mosaic is just now getting set up off-ship; it will be a week or two before we know if the ice at their floe is thickening at all and if so, at an expected rate.

The algal bloom may extend north to the PS's location and beyond under <1m ice once its snow cover is gone, especially under glassy melt pond sites. While sunlight is minimal now, algae may have captured its heat earlier in summer just below the surface of the ice (rather than letting it pass down in clear water to depth). Peak adsorption wavelengths for chlorophyll A are at 465 nm (blue) and 665 nm (red) whereas green is reflected back up. However algae have many secondary pigments and also backscatter.

This is one of the three main themes of Mosaic research but not one that likely to produce near real time outputs for us to illustrate or analyze.
Title: Re: MOSAiC news
Post by: Threebellies on October 09, 2019, 11:27:28 PM
This search for a suitable floe is ongoing

This has become a common problem for placing instruments on the Arctic ice. It also means measurements are being done under unrepresentative conditions.

Using sampling to ultimately estimate the conditions of the entire Arctic via statistical analysis requires representative (usually random) sampling but this is no longer possible. The result is likely over estimation of sea ice thickness and stability.

Not only that, it’s indicative of a paradigm shift. If ice conditions aren’t good enough to take proper samples, well, that suggests we’re a lot closer to a BOE event than some would acknowledge.

Voyages should be done like this yearly, I wish we had this back when there was actually sea ice and not slush up there.
Title: Re: MOSAiC news
Post by: uniquorn on October 10, 2019, 12:30:10 AM
crop of the mosaic multisensor map, oct7-8 showing ~20km south eastward drift since yesterday. An interesting start to this expedition. Red and white bar at the top is 20km
Title: Re: MOSAiC news
Post by: jdallen on October 10, 2019, 07:28:31 AM
It's not entirely clear that melt season is over in some parts of the Arctic Ocean.
It's pretty clear from the temperature data, the extent/area data and the sensor data from sources like Mosaic that the transition from melt to refreeze is no where near as distinct as it was prior to the last decade or so.

We are already seeing Arctic breakouts.  Heat intrusions above 75N are continuing pretty much unabated.  I suspect Mosaic will not show signs of either significant thickening or serious expansion of the pack into the peripheral seas for quite some time.
Title: Re: MOSAiC news
Post by: A-Team on October 10, 2019, 10:14:34 AM
transition from melt to refreeze is nowhere near distinct
Right. The 1D extent graphs don't capture geolocated nuances.

It turns out to be easy to pattern-match radar images of the Mosaic floe in early October back to visible images in Worldview in late September (before it all went dark) because in context, the floe moved as a mildly distorting rigid body over this time frame.

This enables convenient determination of the floe's provenance, daily displacements and deformations using the animation feature of WV on clear days back to 18 Mar 2019 when WV first had enough light.

Note the Mosaic radar archive goes back to Sep 8th and is cloud-free unlike visible. However its resolution is inconsistent, with a big jump on Oct 7th after the floe was selected, plus it suffers from a now-irrelevant ship track overlay. In #74, the floe is tracked back to Sept 21 in radar.,2906.msg232032.html#msg232032

However PolarView goes back even farther with its Sentinel archive. However visible and near infrared carry other information such as surface temperature, insolation history, proximity to algal blooms and wildfire soot deposition.

Because this floe will be so intensively studied over the next year, it is important to walk it back in time to better understand its 'initial state' in the Mosaic project.

The last 30 days of sea ice motion suggest that the floe has experienced very little net tendency towards resuming TransPolar Drift. The floe may have been in sub-100% concentration (light blue in OsiSaf) in mid-Sept and earlier.
Title: Re: MOSAiC news
Post by: A-Team on October 10, 2019, 12:47:35 PM
Mosaic buoy data to date can be checked here. There are 16 surface velocity profilers so far; the downloads clean csv text files with hourly lat/lon to 4 decimals, drift speeds to 3 decimals in m/s, and surface temperature to 1 decimal.

However they don't triangulate the buoys nor give the ensuing Delaunay deformation over time, for which 16 Excel sheets is ideally suited (and Goog Earth Pro freeware for the graphic animation).

This is an example of where a forum member could add value to Mosaic by using the online distance tool that Uniq provided earlier. GPS positions are always given relative to the WGS84 ellipsoid of revolution rather than the earth sphere or actual geoid (available as the first 100,000 terms of a spherical harmonic expansion).

The AWI help desk writes that a more interactive version which will be online in mid November. [Hallo? Bei uns wäre diese grundlegende Softwareaufgabe erledigt gewesen, bevor das Schiff gesegelt wäre! Zur Sicherheit muss der Polarstern nahezu in Echtzeit wissen, wie sich die Belastung im Eis aufbaut, nw?]

I'm mildly astonished that oceanographers have not set up an online tool that does this.The triangle math is from the Babylonians 4000 bce, the rest was published in 1934 by a Russian descendant of a French officer captured during the Napoleonic invasion of 1812. It is not especially computationally expensive: the algos are seasoned github deposits for video gamer programmers.

The geometric set-up is very similar to USGS arrays to monitor nrt tectonic plate collision in Nevada and so earthquake strain in southern California (though some of that is interferometric as displacements are in microns). This is the PS's concern as well: sudden opening of leads and rapid formation of pressure ridges.

I could see it taking me a couple hours to start supplying the PS with nrt continuum mechanics in its immediate vicinity (but surely they have laptops on board?). Because the buoy gps is so accurate, this might improve on whatever deformation overlay they have on PS bow radar, though that would be really rt instead of hourly.

The issues are kriging up the resolution and assimilating the observed current system of S1 rifts. The ambient ice has been under extensional tension rather than compressional.

The explanation for the visualization delay must be that buoy arrays have rarely been deployed in ice: the Arctic Ocean has long been seriously under-instrumented. So three cheers for Mosaic's deployments -- this should have been done every year since Iridium went commercial in 1998.

Found a buoy forensics match to the first deployment question in #40 and chased down how we got to the words 'buoy' and 'die Boje' (plural Bojen). The English pages at Mosaic are sometimes delayed a few days.
Title: Re: MOSAiC news
Post by: uniquorn on October 10, 2019, 08:40:25 PM
Nice detective work. Don't we need to see the overall buoy set up before launching into continuum mechanics? edit: not that I know how to do that ;)
Based on today's multisensor map I think I've located a buoy on or very close to Polarstern for the last few days. iabp 300234068213470. I'm not sure if this is value for MB but here is it's drift track since records started.
GFS forecast (from Nullschool) shows a yo-yo swing in temperature in the vicinity of Polarstern over the next 24 hours or so.

By 12 UTC on 8th Oct, a plume of mild arrives up from Svalbard, yielding temperatures slightly above 0 C but it is short lived and 12 hours later at 00 UTC on 9th Oct, it forecasts temperatures below -10 C as cold air is advected across the Pole from the American side towards Russia.
warmest temp was -2.4C, still quite warm. Of course, it might be sitting in the hold somewhere so the temps might not be relevant. The drift should be valid though.
edit: tech note: gif is optimised to reduce size in gimp, it may be necessary to deoptimise if downloaded. OT they must be an amusing bunch at iabp
Title: Re: MOSAiC news
Post by: uniquorn on October 10, 2019, 09:20:19 PM
Thanks to meerisportal and the mosaic team, here are their prepared buoy charts.
Grosfeld, K.; Treffeisen, R.; Asseng, J.; Bartsch, A.; Bräuer, B.; Fritzsch, B.; Gerdes, R.; Hendricks, S.; Hiller, W.; Heygster, G.; Krumpen, T.; Lemke, P.; Melsheimer, C.; Nicolaus, M.; Ricker, R. and Weigelt, M. (2016), Online sea-ice knowledge and data platform <>, Polarforschung, Bremerhaven, Alfred Wegener Institute for Polar and Marine Research & German Society of Polar Research, 85 (2), 143-155, doi:10.2312/polfor.2016.011.
Now to set them all up from the same start date/time and see where they all are :)
(english version)
seem to have lost the buoy names somewhere....fixed
Title: Re: MOSAiC news
Post by: uniquorn on October 10, 2019, 10:12:16 PM
A brief break in the clouds. Worldview, mosaic rough location, 84.9N 135.7 (no timestamp on worldview)
Title: Re: MOSAiC news
Post by: A-Team on October 11, 2019, 12:16:54 PM
WV graticule? need final set of buoys? buoys too near the Polarstern? Physics of materials?
Spectacular VIIRS above ... but when I went to the link, it had been over-written by something unrecognizable. That happens all the time at WV as swath updates roll in. I suppose the bright networks of veins are leads (resp. thin ice) with warmer water showing through. These might be worth mapping as lead openings are recurrent weaknesses.

The 43 page explainer for the Visible Infrared Imaging Radiometer Suite is here:

WorldView doesn't do graticules well, 80º is the first latitude out from the pole with 30º increments on longitudes. Better if NASA provided options for controlling the OpenStreetMap vector graticule and fixed code so animations captured it. It's possible but inconvenient to capture the timestamp on a per swath basis which is critical to synching with other satellites.

While WV does have very accurate mouse-over lat/lon in the corner, those don't stay tied to a floe after image save or screenshot. Mosaic Multisensor offers a very nice graticule on their higher resolution images (from Oct 7th on).

For WV, if your save includes long lines intersecting the 80º circle, that chord length is enough to accurate rescale AMSR2_Large and capture its graticule as overlay for 75º and 85º plus 1º longitude increments.


The ship itself is one big fancy drift buoy, not only reporting its GPS but also whatever parameters those six containers of atmospheric instruments in the bow are recording. Plus its azimuthal heading which the surface velocity profilers do not provide.

A rigid body can undergo translations (GPS) and rotations (azimuth changes) that are not relevant to the brittle failures of concern (opening and closing of leads, over-rafting of floes, slip-strike shearing and pressure ridges/keels).

Mosaic actually likes leads because they release ocean heat to the atmosphere and are important to study for overall energy flows, just not leads that cut LAN and power lines and strand personnel at field stations.

Taking any three buoys that define a good triangle (not co-linear, no overly acute angles), the lengths of the three sides and area enclosed do not change over time in a rigid ice pack. If the area increases, it means leads have opened under extensional forces; if the area decreases, compressional collapses have occurred.

If say 70 buoys are deployed, a goodly system of coupled triangles (the perimeter being the convex hull) emerges for monitoring regional ice deformation. Here ice brittleness increases non-linearly with colder temperatures. Since the SVPs record air temperatures at the ice surface and since the seawater underneath the ice is clamped to -1.7ºC, the temperature profile through say 2m of ice can be estimated.

Mosaic has two different buoy scales, high resolution local on and around the chosen floe and more sparsely regional. There aren't enough buoys out there to do the whole basin. There has been talk of large-scale air drops of passive devices like radar corner reflectors that would show up as points of light on Ascat etc. Hasn't happened.

Someone posted a great animation (can't relocate :() of the ice temperature profile behavior under an upper sinusoidal (seasonal) boundary conditions, plus an explicit solution of the governing heat equation. Thus if the a curve is fitted to the buoy's hourly temperatures, each term in its fourier expansion will have an exact solution -- and these are additive solutions.

However real ice has many issues such as surface snow and its complex aging status, frozen-in air bubbles, variable salinity inclusions, brine pockets, crystal dislocations, adherent algae and copepods etc etc meaning that the heat conductivity parameter isn't constant or known. So it is easier just to freeze in a string of thermistors below the buoy.


We can do a lot better than that cramped meereisportal visual just with a drag-n-drop of all the buoy lat/lon columns onto google earth pro. The advantage of GEP is the liquid rescaling to any zoom, a free parameter for temperature or thickness and mouse-over popups; the disadvantage is there does not seem to be a digitized daily ice edge line around. However there is a way of auto-generating that from say the AMSR2 blue edge.

GEP barely pauses loading a kml file with 250,000 lat/lon waypoints. That would be 30 buoys reporting hourly for a year. Hourly is a bit much given slow drift speeds but it is great for dynamic triangles. There is very little overhead to drawing lines between buoy pairs with the same timestamp.


The AMSR2 images below compare the ice edges on the Siberian side south of the Polarstern on Oct 10th for 2013-2019 (the 2012 is not provided by the UHH archive). The large format 3.125 km does notably better on growing landfast ice. This narrow strip is difficult to image because of the irregular coastline can occupy part of rectangular gridded pixels.

Clearly autumn 2019 is off to a very slow start; the magenta overlay line on earlier years shows how much open water is still left in the Laptev, the star at bottom shows the Polarstern location. I don't expect the 500 km reach of open water to freeze over any time soon because shallow shelf water been increasingly affected by Atlantification. The Laptev had frozen over completely in 2012-13 by the first of the year.
Title: Re: MOSAiC news
Post by: macid on October 11, 2019, 01:47:19 PM
Animations of buoys drift speed attached, code on my github, it should be possible to take a set of buoys and calculate their movements respective of each other.. interesting idea

there's accelometer data in the buoy data as well, I assume this can be related to wave height or ice bits bumping into each other?

Also if anyone has good data files for ice concentration/movements please let me know. I saw AMSR2 has hdf files but they're a bit of a pain, preferably something with coordinates.
Title: Re: MOSAiC news
Post by: uniquorn on October 11, 2019, 08:06:40 PM
Good step forward on buoy analysis :).
polarstern temps for niall, half a yoyo
Title: Re: MOSAiC news
Post by: A-Team on October 11, 2019, 08:28:37 PM
should be possible to take a set of buoys and calculate their movements respective of each other
Quick and easy way to do that on a massive scale -- # of buoys and # of times -- is a database mail merging into kml template (keyhole markup language, human readable text like html), let Google Earth do the scalable display over a bathymetry background plus calculate all the distances and polygonal areas for you to very high WGS84 accuracy and then load it up on a web browser so clients don't need GE installed.

Just look at the attached txt file for the triangle ... it's so easy, it's so easy to parse it out and drop into their display engine.

The SVP buoy 2019P152_300234068218450_proc.csv weighs in at just 16 kb for 299 lines. The three buoy triangle, 1 kb. So not talking serious text wrangling here with a few dozen buoys for a year; in SV days our group was knocking out 16 terabyte based scientific displays, trillions of buoys.
Title: Re: MOSAiC news
Post by: Niall Dollard on October 11, 2019, 10:31:18 PM
Good step forward on buoy analysis :).
polarstern temps for niall, half a yoyo

Thanks for that plot Uniquorn. So didnt quite reach positive values.

For yo-yo temperatures, it's hard to surpass the eastern slopes of the Rockies. Denver drop of 39.5 C in 36 hours !
Title: Re: MOSAiC news
Post by: blumenkraft on October 12, 2019, 07:41:02 PM
Life aboard the RV Akademik Fedorov

Title: Re: MOSAiC news
Post by: A-Team on October 13, 2019, 01:18:15 AM
Update: the differencing of successive days of AMSR2_large is an effective way of visualizing closure of the open gap between the Polarstern and the Siberian shoreline: central ice pack edge growth meets growing landfast ice. Growth of that is just now kicking in.

I was just barely able to scale down mosaic.multisensor to overlay the Polarstern drift path on the 3.125 km resolution AMSR2; this require downsizing the radar original to 0.45% to get the path scaled (no sign of TPD yet).

There are a lot of ways to slice and dice the buoy data, the first substantial nrt data set we’ve had to work with, other than satellite products, since the ice penetrating radar archive for Greenland. In past years, 0-1 buoys have been reporting, often defectively, in the entire Arctic Ocean whereas now we have a large active coupled buoy array in the vicinity of the Polarstern..

The data archiving is still a bit rough, for example the second set of buoys below don’t measure snow depth or ice thickness as their meereisportal table indicates. However provisional graphs of temperature and speed are provided as a convenience and updated daily.

The Polarstern itself behaves as a giant buoy since being stably moored on Oct 4th. No hourly database for it accompanies the others. The radar image archive shifted to high resolution on Oct 7th. The pixel dimensions shifted inexplicably from 3500 x 4304 to 3498 x 4302 between the 7th and 9th, causing stacking issues. (Inexplicable because the crop tool has a fixed-size checkbox in all known image software.) The timestamps are all 0500 UTC; lat/lon of the Polarstern are not provided in the extensive legend.

The Sentinel images have different pixel offsets each day. Lagrangian coordinates (co-moving with ship) are being used; they cause havoc with the graticule and drift course overlay. It's more common on satellite series to use fixed eulerian coordinates to illustrate floe and lead dynamic development.

The first set of RSAQUA-type SVP buoys was deployed by Chinese scientists. These measure GPS position every hour along with temperature. From lat/lon they derived displacements (not shown) by an unknown equation (vincenty? haversine?), from which speeds were determined hourly. These buoys do not carry a wave heave accelerometer. Tides in the open Arctic are too low and slow to give a reading.

I checked into measurement error. One degree difference in latitude on the WGS ellipsoid is 111,111 meters. The GPS is reported to 1 part in 10,000, meaning 85.1234º can barely be distinguished for 85.1235º. Thus the positional uncertainty is 11.1 meters which is inadequate for a cruise missile but plausible this far north.

In calculating items like the changing sides and angles of a delaunay triangulation array, no purpose is served by exceeding the accuracy of the data.

It appears the buoys do not track azimuth. That is, unlike a ship, there is no natural axis unless the floe itself is stably asymmetric. Rotation of the floe in which the buoy is frozen is thus difficult to disentangle from translation.

We have measured large floes spinning around and around in the Beaufort arm eddies in previous autumns. In the vicinity of the Polarstern, the ice is mainly moving en bloc. The arm is forming nor this month and will likely extend up the Alaskan coast to the Chukchi before turning north. The ice will not move in a gyre, it hasn't for over a decade.

A column for changing bearing angle can be added using batch online tools (or spreadsheet formula). I did this for 2019P152 using positions 24, 48 and 72 hours apart; to the extent calculated bearings change more than the track implies, the floe has rotated. Bearing, heading and course are a source of perpetual confusion but see:

There is no column for changes in drift speed (acceleration) but that is implicit as the slope of the tangent line to the speed graph (below). The one I looked at 2019 has a puzzling periodicity. Obviously if other 11 buoys don’t follow in parallel, they are diverging/converging and the ice in between is deforming.


D Watkins, a grad student at Oregon State who studies ‘Arctic lower tropospheric temperature inversions in the CESM large ensemble’ deployed a second set of nine buoys (brand not provided) from the helicopter of the Akademik Federov.

2019P188  2019P196
2019P190  2019P198
2019P191  2019P200
2019P192  2019P203  2019P206

These buoys apparently do have an onboard accelerometer, though the column heading is "accelometer_variance ()" with units omitted but values ranging from 5 to 15. It’s not clear why the buoy should expect any waves in the next 8 months. I tracked down an explanation of sorts from NDBC not specific to this particular buoy:

How are spectral wave data derived from buoy motion measurements?

NDBC-reported wave measurements are not directly measured by sensors on board the buoys. Instead, the accelerometers or inclinometers on board the buoys measure the heave acceleration or the vertical displacement of the buoy hull during the wave acquisition time. A Fast Fourier Transform (FFT) is applied to the data by the processor on board the buoy to transform the data from the temporal domain into the frequency domain. Note that the raw acceleration or displacement measurements are not transmitted shore-side. Response amplitude operator (RAO) processing is then performed on the transformed data to account for both hull and electronic noise. It is from this transformation that non-directional spectral wave measurements (i.e., wave energies with their associated frequencies) are derived. Along with the spectral energies, measurements such as significant wave height (WVHGT), average wave period (AVGPD), and dominant period (DOMPD) are also derived from the transformation.
Title: Re: MOSAiC news
Post by: blumenkraft on October 13, 2019, 05:12:40 AM
The official trailer is quite heroic.  ;D
Title: Re: MOSAiC news
Post by: gandul on October 13, 2019, 01:28:16 PM
The official trailer is quite heroic.  ;D
It's just this Zimmer-esque soundtrack that is used for almost everything now, even for Trump Twitter videos.
I see science heroic but on the quiet side. But well OK.
Title: Re: MOSAiC news
Post by: A-Team on October 13, 2019, 05:54:10 PM
Mosaic is posting the daily location radar in quasi-lagrangian coordinates, with the point position of the Polarstern and the North Pole determining the moving axis. In normal ship-based lagrangian coordinates, the bow-stern center line and main mast would determine the coordinate system (alternately some asymmetry axis on the floe to which the Polarstern is afixed). The difference is in how rotation is represented.

We are more used to eulerian coordinates in satellite archives where the graticule stays fixed. We went through this all before in the time of Ptolemy and Galilleo.

Whoever painted on the red lines and circle, over-writing the value of the most important pixels, seems not have centered them accurately on the ship which shows clearly as a bright white dot (all that metal reflecting Sentinel's beam back). Perhaps those circles reference a valid timestamp but one different from the S1 which would appear in its file name had it been correctly cited.

At any rate, I adjusted the six dates for which for which they archived S1 at higher resolution, so from Oct 7th to Oct 12th so far. As noted above, some of these are either mis-cropped or slightly rescaled from the others. The Polarstern tied on Oct 4th but those dates are missing (4-6 Oct).

We need to go back to the original files and do this over, right. I am not sure though that all of them are S1 as it does not seem that polarview carries them all at the needed resolution. If so that would mean a tedious navigation deep through the ESA server.

At any rate, despite the visual competition from the crazy graticule and red paint, it was possible to re-register six days of imagery. The four gifs below present the data at four levels of zoom. A lot could be said about leads opening and closing, scene deformation, rotation of the PS floe and so on. These run at 150 ms per frame; download and view frame by frame. I also prepared a single concatenate mp4 that has a better controller but am out of attachments here.
Title: Re: MOSAiC news
Post by: be cause on October 13, 2019, 08:24:01 PM  is taken from Andreas T's post on the abandoned Mosaic project thread and covers a similar journey a few years ago .. a good read . b.c.
Title: Re: MOSAiC news
Post by: A-Team on October 13, 2019, 11:31:20 PM
New snow buoy deployed by Mosaic on Oct 11th. These seem to work by taking four sonar measurements from above, with calibration of actual snow at time of deployment. The sonar footprint is about 10 sq meters ... necessary because the snow pack is quite variable and subject to drift accumulations (or bare ice spots).

Again, the manufacturer of the device are not provided; very likely the listed contact M Hoppmann of AWI can provide details. However the device is probably very similar to snow buoy 2014S12, deployed during Polarstern cruise PS82 though that one also measure internal ice temperature. Again, it is not the ice mass balance buoy that meereisportal keeps referencing (crossed out below).

The database fields here can be readily integrated with the other 16 sea ice drift buoys in the growing array and its track displayed in GEP as before. Since all the buoys so far are reporting hourly on the hour, that can be used as the indexed field for a single composite flatfile db with just the essential lat,lon column + one additional parameter of choice.

This will allow individual tracks of the entire 17-buoy array to be displayed over bathymetry and coastline with either Voronoi or Delauney triangulation, with easy updating since the year is just getting started. This is just a paste into a kml template, not rocketry science.

time hourly on the hour   
latitude (deg) to 4 decimals
longitude (deg) to 4 decimals
distance_to_surface_1 (m)   
distance_to_surface_2 (m)   
distance_to_surface_3 (m)   
distance_to_surface_4 (m)   
barometric_pressure (hPa)   
temperature_air (degC)   
temperature_surface (degC)
Title: Re: MOSAiC news
Post by: A-Team on October 13, 2019, 11:44:09 PM
Here are those additional floe tracking time series mention a couple of posts back. The first concatenates four levels of zoom into a movie with frame controller; the second presents 07-12 Oct 2019 data in eulerian coordinates that are better if overlays with other satellites are planned.

Here I used the .avi export option out of ImageJ and converted to mp4 with the free online tool:

The concept of a massively coupled buoy array is new and not fully implemented at meereisportal. The buoys are already experiencing glitches -- whether at the level of sensors, Iridium transmission or IT processing station at AWI I couldn't say -- that result in missing timestamps, eight in a row (4 hrs) for P152 and one for P188 (below).

These data gaps are not indicated by NaN or dashes as they should be; the csv files just skip the lines with no indication. Consequently, each person using the files has to run a separate detector for them (a new column subtracting consecutive time stamps sorted for anomalies).

The gaps then need to be filled in, most easily by linear interpolation from the lines above and below. If the csv isn't repaired, graphic representation of the buoy will be misleading and worse, be out of temporal synch forever more with locations of the other 16 buoys.

Some of buoys are reporting hourly, others twice hourly. If this seems excessive, it can be reduced to every 4, 8, 12, 24 hours by windowing with an appropriate fill-down averaging column followed by remainder (modular) arithmetic in the spreadsheet that consolidates all the individual buoy reports.

This master spreadsheet has one column for common time, lon and lat columns for track plotting, a column for displacement and a free column depending on what the particular buoy measures (air temp, snow depth etc). So far I have only put 4 of the 17 into a master. It starts 04 Oct 19 when the Polarstern first moored.

Then there is the matter of updating, say adding incoming data once a week. It's probably better to start from scratch rather than just appending because some of the data gaps might have been repaired and new buoys might have been deployed.

Meereisportal has not implemented the Polarstern itself as a buoy. While it is surely collected, I don't where that location data is posted in a compatible format.

Since the buoys are quite co-localized now, there may be grid regularization advantages in setting up companion files for virtual buoys (stable features on ice radar). This could only be done once a day, not hourly, and involves manual observation and recording.

The initial locations at deployment of the 17 buoys (at various dates) are shown in a broader context in the GE screenshot (orange polygon). The magenta and green circles show the largest possible free rotations of the ice pack without coming up against fixed land; green is restricted by the de Longa islands. The centers, called the poles of inaccessibility have been determined very accurately in recent papers.

Sort Active     Name       Long     Lat
 5   07.10.19   2019P188   135.99   84.71
10   05.10.19   2019P193   135.97   84.77
 7   07.10.19   2019P190   135.29   84.69
14   07.10.19   2019P200   135.06   85.00
15   07.10.19   2019P203   134.84   85.07
16   07.10.19   2019P206   134.48   84.97
13   07.10.19   2019P198   134.29   85.07
17   02.10.19   2019S92    134.24   84.78
12   07.10.19   2019P196   133.98   85.00
 6   05.10.19   2019P189   132.59   84.70
 9   07.10.19   2019P192   132.57   84.65
11   05.10.19   2019P194   132.07   84.71
 8   05.10.19   2019P191   131.71   84.66
 1   29.09.19   2019P152   125.86   84.24
 2   29.09.19   2019P155   125.23   83.78
 3   28.09.19   2019P156   121.26   82.09
 4   26.09.19   2019P157   119.25   81.39

GE line formatted:
134.29,85.07,0 134.84,85.07,0 133.98,85.00,0 135.06,85.00,0 134.48,84.97,0 134.24,84.78,0 135.97,84.77,0 132.07,84.71,0 135.99,84.71,0 132.59,84.70,0 135.29,84.69,0 131.71,84.66,0 132.57,84.65,0 125.86,84.24,0 125.23,83.78,0 121.26,82.09,0 119.25,81.39,0
Title: Re: MOSAiC news
Post by: A-Team on October 15, 2019, 01:05:26 AM
The first image breaks the latest radar image of the Polarstern's route into daily segments by using successively earlier dates (which have to be moved to align under their co-moving frame reporting).
Once again, we see that net travel over a week is far too long to resolve actual distance drifted by a factor of 3x here.

A junior scientist onboard twittered their initial mooring position in decimal minutes (!) as "84º04.582' 134º25.769' at 9:30 pm Friday boat time (!!)". I could not confirm that ship time used is UTC but would hope so. The PS may know its GPS position better than the buoys: 84.07637 134.42948 which suggests 1.1 m accuracy but that is not entirely clear.

If the adjacent ice pack were moving as a rigid non-deforming block, the buoys would all change speeds in concert. They don't quite (slide show, 4 PRIC buoys).

Esther Horvath has been taking some great photos from the PS. The ice thickness looks barely able to support some of the heavy gear that has to be set up on the ice, such as the 'Ocean City' electric hub. has high resolution photos on the side. has good posts from the Polarstern
Title: Re: MOSAiC news
Post by: A-Team on October 15, 2019, 05:16:04 PM
Update on the position of the Polarstern and the ice immediately around it, eight days to 14 Oct 2019. The selected floe continues to drift the wrong way (south towards Siberia). The icepack edge has scarcely advanced towards Russia or Alaska in recent days though ii is almost all thickened beyond the 0.5m sensor cutoff on SMOS.

The floe has not rotated so far despite a multi-day ice cyclone sweeping up from Banks Island (green over-tint, lower left OsiSaf). 

Although ice movement is strictly wind-driven (subject to boundary conditions and internal cohesion), it rarely corresponds to anything seen in GFS near-surface winds at nullschool. We lost daily coverage of ECMWF in the forked code when Arctic view was killed for lack of sufficient clicks. 

I sincerely doubt that GFS will assimilate data from Mosaic buoys and Polarstern any time soon though that would improve its initializations and ever-changing near-term forecasts.

Only spotty information has been released to date about the selected floe's ice thickness, snow cover, lead/ridge/keel structure and historic provenance despite many EMBird transects flown. S1 radar shows north and south regions of the floe as quite dark (poor return of impinging radar beam) with a better reflecting (whiter) speckled east-west stripe.

This can tentatively be interpreted in terms of near-surface dielectric: dark areas are older ice that are farther along in extruding brine pockets that form during freezing, lighter areas are newer, speckled surface arise from fusion of two floes via freeze-over of intervening sea water and collisional compression into ridges and jumbles. The ice is so thin though that salt left by over-washing waves sometime in the past has affected the surface.

If so, the Polarstern is moored to the weakest part of the floe. However I don't expect shearing here because a number of old leads can be seen opening and closing in the near vicinity; these will accommodate regional ice strain.

The fourth image, taken from Uniq at #82, shows the Polarstern's floe without all the disruptive overlays. I made some very slight improvements in image quality by linear contrast spreading, weak adaptive contrast enhancement and unsharp mask. Two off-the-shelf indexed color palettes provide a start on ice classification based on radar reflectance (residual near-surface polarity).

It is possible, with a big handful of €€€s, to order up much higher resolution SAR imagery of the floe. Possibly that new company would do it gratis for the press. It's too late to order visible as the cloud-free sunlit window closed Sept 24th.

What is causing these wild swings in overall light/dark radar contrast in successive days at the same spot? Maybe S1A vs S1B or ascending vs descending orbits. Hard to say, they don't provide image identifying numbers.

The buoy data is like that too, referenced with shipboard chatter. Buoys are required to have a unique IMEI to transmit wireless data; that identifier is their real name. The IMEI then is tied 1:1 with 2019P155 etc so informally P155 (as other years are not involved).
Title: Re: MOSAiC news
Post by: uniquorn on October 15, 2019, 09:53:07 PM
An update on the meerisportal buoys on macid's post upthread, tinkering with the code a little enables us to zoom in on the 12 buoys closest to the polarstern location. Still not sure which is the most flexible buoy analysis tool.

polarstern temperatures from sailwx

a crop of today's polarview jp2, linear contrast. 2 very bright radar reflections to the rhs. A new part of the mosaic installation?
Title: Re: MOSAiC news
Post by: A-Team on October 16, 2019, 12:35:57 AM
tinkering with the code a little enables us to zoom in on the 12 buoys
Very nice! Most excellent progress on a viable multi-buoy display. It maps polar coordinates to cartesian, similar to mapping the earth ellipsoid to a mercator cylinder rolled out to a flat tangent plane. This will work quite well as long as the buoys are clustered near each other. As the year goes on, they will disperse all over the Eurasian AO and distortion will increase unacceptably.

I looked at putting another nice ice graphic by E Horvath of the Polarstern parked at its floe underneath the sprites ... so-so outcome to date.

Buoy repositories are popping up all over, which is great for data availability. These are being structured as relational databases rather than flat-file; for example Meereisportal is putting auxillary flatfile dbs in mouse-over notes.

Any relational db can be accommodated in a flatfile like excel. However that is very inefficient and a great many cells will be empty. Relational db are constructed relative to a master key (buoy indexing file) which in this case is the mandatory IMEI mobile device number.

That is the counterpart to the latin binomial of a plant, eg Dryas octopetala. There, just like with the buoys, divergent common names are used mountain avens, eightpetal mountain-avens, white dryas, and white dryad. (And that's just english.)

What I’ve seen so far is not going to scale for coordinated analysis of say six dozen buoys posting 5-6 columns of data 48 times a day over a year (7,568,640 cells).

In my view, a front end is needed that allows the data set to be sensibly queried. For example, someone might want only buoy data over a specific time frame, from only buoys within a specified initial radius of the Polarstern that have both air temperature column and snow thickness with no more than 2% NaN gaps.

For this, a natural choice would be (open source, highly developed, widely used) MySQL rather than proprietary software or ad hoc code. While this could/should have been up and running using proxy data given eight years of Mosaic planning, it wasn’t. These sites are not going to restructure mid-season but rather dig themselves in deeper.

2 very bright radar reflections to the rhs. A new part of the mosaic installation?
Do we have lat/lon for them? They may not be buoys but rather passive metal containers/reflectors like the 'Ocean City' transformer. Alternatively, they could be rfi (radio frequency interference) from active emitters that sometimes plague Smos and AMSR2 (despite reserved frequencies).

In the 122-page planning document, it's noted that all electrnic devices on board must be a signature registered with the ship because with 300 tons of equipment, some rfi is only to be expected initially. Email to 50 kb text is allowed to anyone appropriate on the ship; no hefty graphics.

@zlabe is posting very useful negative NAO anomaly graphics bimonthly which are something Mosaic needs to keep an eye on if they want transpolar drift. Not that there's any way to flip negative to positive. I've attached the daily pattern since mid-March.
Title: Re: MOSAiC news
Post by: uniquorn on October 16, 2019, 07:42:23 PM
Today's polarview image, this time showing the jpg with graticule (no contrast change),
The longitude lines are 132 and 128E
Maybe too much movement from yesterday in the 3rd reflection for a tethered object.
edit: obviously it was AF that moved, see gif below, click to run, click all images for full resolution.
more edit:
 jp2 saved as png with linear contrast and a smaller crop jp2@200% bicubic>png  (honester ;) ).
struggled a bit with the gimp contrast but this should be linear
Title: Re: MOSAiC news
Post by: A-Team on October 16, 2019, 10:15:09 PM
16-bit p2 saved as png with linear contrast and the same jp2>png default (honest
Wie, bitte? On these large 16 bit jp2 that open as 16 bit in current versions of Gimp but not ImageJ, the contrast and resizing tools will work for initial steps at the 16 bit level. This provides a huge advance in opportunities over 8-bit because the pixel value histogram, which is initially a cookie-cutter gaussian distribution, doesn't bin up as contrast tools operate, introducing visually apparent round-off errors. (The 16-bit also has to round calcs but the error is out in weedy decimals and is discarded later.)

Here the jp2 might open as color but it is really just one-channel grayscale, like an Ascat gif. Those i put into 8-bit gray, then bump in 16-bit and sometimes 32-bit before running re-sizing and contrast tools. However it's ultimately necessary to drop back down to 8-bit when pasting back and forth with Gimp or posting to forum.

We very much want to get the best possible radar image of the floe and surrounding area, optimally enlarged 2-3x with bicubic while still in 16-bit, because yesterday the Helmholz blog posted two very important high resolution images of floes made with via sled and helicopter instruments.

The Sentinel images come as 'Greenland down' so need a 180º rotation to get north up to match. This is a integer matrix transform which does not recompute splines and so has zero effect on resolution at any bit depth.

The Polarstern also has access to TerraSAR-X (DLR) which is one of these crazy public-private partnerships where the public pays once but pays again to see. Canada likes this too; only oil and mining companies can afford the imagery.

Just asking for a friend: Do CA and DE pay for all the multi-billions of satellite freebies that NASA puts online? Do they pay for all the multi-billions of medical genome data the US gives away? Do they pay for use of GFS; do we pay for ECMWF built off our satellites?

One of the prime objectives of Mosaic -- since a ship cannot always be out there -- is to improve interpretation of daily satellite imagery. Here we have mildly dated RGB and VIIRS band 31 images of the selected floe (ausgewählten Scholle) but daily tag-along Sentinel radar for the coming twelve months.

The Mosaic time posted a very interesting graphic of GEM-2 EM ice thickness over a high resolution radar of a floe they investigated early on but didn't choose. The date, scene ID number and grid scale aren't provided nor is the latitude (~85º?) though it lies along 137ºE. Again, better to provide layers so people can see what is buried under the opaque swath lines.
On board 10 Oct 2019 by Stefan Hendricks and team:

…  to measure each floe’s thickness we used the Polarstern sled's built-in electromagnetic ice-thickness sensor. By combining our findings onsite with the radar images from the satellites, we arrived at an overview of the ice situation in the region. Lighter areas on radar are associated with rougher surfaces characteristic of thicker ice; darker radar returns with thinner smoother ice.

The other tool is an airborne laser scanner (ALS) which can detect fine-scale changes in surface height below the helicopter. The sensor has a 300 m swath. The floe is ~2500 x 3500 sq meters.

What we found: the vast majority of the floes surveyed consisted of very thin (30 – 70 cm) sea ice and had meltwater ponds (Schmelztümpeln) that had since frozen over, a clear indicator of intensive melting in the summer, on much of their surface area. Floes of this type can easily break apart or be pushed together, which makes long-term, continuous monitoring and measuring work highly problematic.

Indeed, in the past few days, heavy winds have produced a number of cracks in the ice of our floe, as a result of which our map is no longer entirely accurate. It’s precisely events like this one that we plan to spend the next year investigating. [[paraphrased]]
The first map shows the Polarstern moored on its starboard side to the floe. The bow is used as center of a polar coordinate graticule and extends out as the 0 of 12 angles set out CCW like wristwatch hours. Latitude circles are set out every 250 m out to about 3 km. North is not indicated but apparently straight up; magnetic north is really problematic at these latitudes given rapid wandering of that pole and erratic drift of the floe.

The color scheme is qualitative: light blue for thin ice, dark blue for thicker and white for elevated ridges and standing ice blocks. Snow depth is not shown. No color scale is provided. This is odd because the ALS is a precision laser. It's not clear whether ALS data has been combined with the thickness sled or is just being used as a freeboard detector.

We'll be referring to this camp map and ice thickness a lot: the direct link to the 3112 x 3691 image is below. I've scaled it down by 3/8 for the forum (to 1140 x 1400, needs click to see) and added a small Sentinel floe scene (to be replace soon by a Uniq jp2.)
Title: Re: MOSAiC news
Post by: A-Team on October 16, 2019, 10:45:02 PM
Whoa ... 600 of them acquiring all this data, a handful of people here trying to assimilate it?

Eight new buoys. These are CTD types: instrumented wires hanging down holes drilled in the ice to 100 m to record temperature, salinity, conductivity, and water pressure at four depths (rather than continuously like a profiler motoring sensors up and down a wire). Not much on surface except air temperature and nrt GPS. These are not ice mass balance profilers as they do not measure thickness or temperature of the ice.

These were basically deployed along 85ºN at various longitudes 131-137ºE so make for a very good set of differential drift detectors. We are up to 25 new buoys with GPS plus the PS.

This is really short-sighted of Mosaic not to name these systematically (who thought of 1,2,...8?) Hopefully Meereisportal will correct it but so far they have not. They should be categorized as Ice Beacons, that is 2019B01 etc.The buoys do have IMEI identifiers. No one is listed as contact. They were deployed from 07-11 Oct 19 on but data first surfaced on Oct 15th.

The slow slide show below shows the results these buoys collected so far.

 time interval: 10 minutes
 latitude longitude (decimal degrees to 1:10,000)
 buoy submerged (yes/no)
 air temperature_at_surface (degC to tenth degree)
 conductivity, salinity, pressure and water temperature at   10m (S/m, psu, hPa)
 conductivity, salinity, pressure and water temperature at   20m (S/m, psu, hPa)
 conductivity, salinity, pressure and water temperature at   50m (S/m, psu, hPa)*
 conductivity, salinity, pressure and water temperature at   75m (S/m, psu, hPa)
 conductivity, salinity, pressure and water temperature at 100m (S/m, psu, hPa)

 S/m: sieverts per meter
 *salinity not reporting

The graphic below has an inset postage stamp of google earth waypoints for the Polarstern made at AWi. The numbers can be scrapped out of text-view from the following snippet of kml:

               133.6,84.8,0 133.6,84.8,0 133.7,84.8,0 133.7,84.8,0 133.7,84.8,0 133.8,84.8,0 133.8,84.8,0 133.8,84.8,0 133.9,84.8,0 134,84.8,0 134.1,84.8,0 134.1,84.8,0 134.1,84.8,0 134.2,84.8,0 134.2,84.8,0 134.2,84.8,0 134.2,84.8,0 134.2,84.8,0 134.3,84.8,0 134.3,84.8,0 134.3,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.4,84.8,0 134.5,84.8,0 134.5,84.8,0 134.5,84.8,0 134.5,84.8,0 134.5,84.8,0 134.6,84.8,0 134.6,84.8,0 134.6,84.8,0 134.6,84.8,0 134.6,84.8,0 134.7,84.8,0 134.7,84.8,0 134.7,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.8,84.8,0 134.9,84.8,0
The right hand side shows a crop of the left hand legend corner of all the mosaic multisensor maps. It shows the ship lat/lon position times are quite erratic relative to (not-provided) radar timestamps. This may explain why the red overlay circles are such a clumsy fit to the actual white pixels of the ship -- different times. It's not clear whether the wavy intermediate transparent red track between my green squares (the actual ship displacement on the day stated) follows actual hourly ship GPS waypoints or is just creatively hand-drawn.

The final graphic illustrates the latest meteorology collected on the Polarstern, something that it has been doing for the last 25 years. This data is sent in immediately to be assimilated for ECMWF forecast initialization (and later re-analysis).

The wind angle graphic is not so easy to read but they provide that digitally as well. Mosaic has a plan for 5-day ice motion prediction (SPIDX?) so real near-surface data will be important to that.
Last update: Wed Oct 16 11:00:01 UTC 2019
Near real time 1-hourly routine synoptic observations
Title: Re: MOSAiC news
Post by: A-Team on October 16, 2019, 11:42:23 PM
Meereisportal just uploaded a whole new batch of floes while I was typing up the post above. There are now 35 deployed.They are playing catch-up, these new ones were set out some time ago.

Their table is quite good, though it could use a couple of columns for latest positions as well as sort options. However the html is clean and it drops right into excel. The attached csv file shows the buoys sorted by name, northernmost latitude of deployment, and reverse chronological deployment order. Be good to add the IMEI and whatever UW buoy center has about them, 2nd link.

They do encourage questions, the Helmholtz blog allows replies, the twitter sites have threads and so on. Below I started on social media translations and site names of the ice camp:

Fortress   Festung
Courtyard   Hof
Outer Wall   Außenwand
Sculpture  Garden   Skulpturengarten
Gatewy   Tor
South Beach   Süd Strand
refrozen ice lead   gefrorene Eisriss?
melt  pond   Schmelztümpeln
Area 3 logistics    Bereich drei

omg   omG
IMO   mMn
RSVP   uAwg
CUL8R   bd
idk   kA

Blue: discussed immediately above
Purple: discussed earlier
Red: need a look

2019O1   84.61   130.65   05.10.19
2019O2   84.56   134.77   07.10.19
2019O3   84.75   136.59   07.10.19
2019O4   84.85   133.76   08.10.19
2019O5   84.92   136.24   09.10.19
2019O6   84.96   130.97   10.10.19
2019O7   84.63   133.60   11.10.19
2019O8   84.86   132.23   11.10.19
2019P152   84.15   124.63   29.09.19
2019P155   83.62   123.58   29.09.19
2019P156   81.85   118.45   28.09.19
2019P157   81.08   116.74   26.09.19
2019P188   84.65   134.41   07.10.19
2019P189   84.64   131.07   05.10.19
2019P190   84.64   133.72   07.10.19
2019P191   84.60   130.21   05.10.19
2019P192   84.59   131.05   07.10.19
2019P193   84.72   134.38   05.10.19
2019P194   84.65   130.56   05.10.19
2019P196   84.94   132.49   07.10.19
2019P198   85.01   132.83   07.10.19
2019P200   84.94   133.58   07.10.19
2019P203   85.01   133.38   07.10.19
2019P206   84.91   132.95   07.10.19
2019S79   84.56   135.50   07.10.19
2019S80   84.86   134.44   07.10.19
2019S81   84.76   137.21   07.10.19
2019S86   84.96   131.59   07.10.19
2019S87   84.92   136.82   07.10.19
2019S92   84.69   132.94   07.10.19
2019S93   84.68   134.74   07.10.19
2019S94   84.97   133.95   07.10.19
2019S95   84.63   134.32   07.10.19
2019S96   84.78   131.82   07.10.19
Title: Re: MOSAiC news
Post by: uniquorn on October 17, 2019, 12:49:15 AM
Plenty to do tomorrow then. Updated my previous post using gimp 2.10.12. Will look through polarview images to see if any have better definition. Here is 400% scale of image above in gimp, saved to png -> imageJ, further linear contrast, adaptive contrast then unsharp mask. It retains a few more features than the standard jpg.  is easier access to iabp .dat files using the 15 digit id.
Title: Re: MOSAiC news
Post by: A-Team on October 17, 2019, 02:01:00 PM
Below I update the daily segments of Polarstern drift to 16 Oct 2019, made an overlay of the drift track on Smos of the same date (where it barely shows, even somewhat exaggerated), and took your best S1B of Oct 6th above and enhanced/enlarged it to fit over the Ice Camp which the S1 radar lacks the resolution to do really. The radar needs a 180º rotation to fit the ship's convention.

That is, the Ice Camp original is posted 975 pixels for 1000 m (did they intend 1:1?) whereas the
recent mosaic multisensor maps have 3797 pixels for 1º of latitude (111.111 km) which is 29.3 pixels per meter. Thus the Ice Camp has a better scale by 30:1

Nonetheless, the fit is quite informative in terms of helping to interpret radar over the wider scene. I am still of the view that the thicker ice in the Mosaic floe is a mashup of two thinner floes, either collision or over-riding. It is FYI that has barely graduated to SYI. The floes all around it are 70-90 cm. The year of Ascat rules out an MYI drifting into this area.

We did find the floe on Worldview for a few days in late Sept (somewhere above). At its best resolution, 9 pixels per 1000 m, even less can be expected for the overlay. Hopefully the Polarstern took visible imagery in early October.

Low sun angle can be extremely effective showing quantitative topographic relief as we've seen at Jakobshavn. If not, they might scan the Polarstern's very powerful searchlights across the scene while a helicopter records from above.

For people wishing to do the daily (weekly?) download of all the Mosaic buoys, simply use a web browser utility that can open a list of urls and save image contents. I obtained this by drilling into the open file system at meereisportal and copying/sorting the buoy directory. The url shown is an example; add the front part to the buoy name + IMEI list. Note 2019S88 is listed but its location isn't relevant.

The timestamp, lat, lon, speed columns are invariably the first four so if that is all you want to plot drifts, there may be some simple way of opening all the downloads in excel as a stack and deleting all the rest. It would be better if the buoys were in reverse-chron order as that would synch the rows of buoys that had different deployment dates. Still, some are on the hour, others on the half hour, skipped times not indicated with empty rows.

Note the confusion presented by 2019O1-O8. These have a zero and a capital 'O' for buoy type. (However Meereis does not have an explanation for this category in its pop-up key.

Title: Re: MOSAiC news
Post by: uniquorn on October 17, 2019, 04:50:58 PM
A quick overview of mosaic Pbuoy drift before moving on to others.
Title: Re: MOSAiC news
Post by: blumenkraft on October 17, 2019, 06:34:40 PM
WOW, you can see the tides!  :o
Title: Re: MOSAiC news
Post by: uniquorn on October 17, 2019, 07:13:57 PM
 Looks like it.
Here showing the Sbuoys drift and air temperature. Will have to work out how to show 'distance to surface' 1-4 later.
Anomalous movement on the last buoy at the end. Have to work out labelling also.
Title: Re: MOSAiC news
Post by: blumenkraft on October 17, 2019, 07:33:08 PM
You and A-Team are doing an amazing job visualizing this stuff. Thanks so much for that.

I hope the folks on the Polarstern follow your work. Maybe get ideas from you? Maybe give us additional data to work on?

One can dream, right? ;)
Title: Re: MOSAiC news
Post by: uniquorn on October 17, 2019, 09:00:43 PM
Thanks also to macid for the original coding. I am just script oldie.
edit: changed animation, temperature at 100m was more interesting. I wonder what is going on down there?
All 36 meerisportal buoys, for the record. Click to run.
Title: Re: MOSAiC news
Post by: A-Team on October 17, 2019, 10:40:01 PM
Grrr... reconciling Meereisportal with UW's IADB global buoy database turns up 73 69 buoys associated with Mosaic. They are all in the 85/136º neighborhood and still actively reporting October 15-17 (except for 2019P16 which last reported on the 11th).

IADB does not allow collection of urls to the data directory; the links on their site are fast but lead to some mumbo jumbo and an onClick .dat file (same as .csv)
<a href="#BumBuoys" onClick="popData(300234010077180);"

The confusion presented by 2019O1-O8: these are not just badly numbered 1-8; they have a zero and a badly chosen capital 'O' for buoy type. However Meereis does not have an explanation for this buoy type in their pop-up key. IADP calls them CTD type which fits their data content.

Tides in the middle of the ocean go up and down, merely 30-50 cm at the locations considered. GPS measures sideways. Tidal currents go sideways but mostly near islands or mainland.

Meanwhile inertial waves (wind-induced, coriolis restoring force) have a 12 hr period whereas tides are more like 12:50. (One of the authors below was my roommate in grad school!). There could also be periodic systemic errors having to do with time of day and the buoys position relative to the GPS satellite constellation

Near-Inertial Wave Propagation in the Western Arctic
R Pinkel

Observations of internal wave generation in the seasonally ice-free Arctic
L Rainville and RA Woodgate

Dynamics of the Changing Near-Inertial Internal Wave Field in the Arctic Ocean
HV.Dosser and L Rainville

Revisiting internal waves and mixing in the Arctic Ocean
JD Guthrie  JH Morison  I Fer

Year-round observations of sea-ice drift and near-inertial internal waves in the Northwind Abyssal Plain, Arctic Ocean
Y Kawaguchi et al

Here are the latest lon,lat coordinates for the 69 buoys in Goog Earth format.

132.11,84.684,0 133.9046,84.6754,0 133.2518,84.9642,0 133.4718,84.6228,0 132.2082,84.7568,0 133.646,84.85,0 130.8486,84.957,0 136.1034,84.9136,0 134.500,84.9796,0 130.35,84.61,0 134.44,84.55,0 136.26,84.74,0 133.48,84.85,0 135.93,84.91,0 130.71,84.96,0 133.29,84.62,0 131.95,84.85,0 131.59,85.05,0 133.94,84.53,0 136.40,84.94,0 135.27,84.72,0 136.89,84.70,0 132.23,84.66,0 135.13,84.79,0 135.39,84.96,0 134.74,84.94,0 131.43,84.83,0 133.68,84.68,0 133.25,84.69,0 131.54,84.79,0 133.16,84.71,0 132.20,84.64,0 132.63,84.72,0 131.93,84.73,0 132.84,84.79,0 132.44,84.69,0 131.55,84.70,0 134.09,84.65,0 129.90,84.60,0 134.07,84.71,0 130.74,84.58,0 133.39,84.63,0 130.76,84.64,0 130.25,84.65,0 132.20,84.94,0 133.28,84.94,0 132.55,85.00,0 133.09,85.01,0 132.66,84.91,0 133.75,84.97,0 132.69,84.69,0 134.80,84.68,0 130.72,84.96,0 131.95,84.68,0 133.76,84.67,0 133.75,84.67,0 134.45,84.55,0 136.27,84.74,0 132.83,84.76,0 132.76,84.76,0 123.98,84.15,0 117.69,81.75,0 115.96,80.96,0 122.91,83.59,0 132.05,84.75,0 124.31,85.85,0 132.15,84.41,0 116.92,85.51,0
Title: Re: MOSAiC news
Post by: A-Team on October 18, 2019, 01:45:41 PM
An extensional crack was reported yesterday out as the meteorological tower was being installed in Met City. The fissure has since widened to 5 cm; the length has not been reported. Np equipment has been lost or damaged.

No map has been provided showing position of the crack relative to the radar image, conceptual camp layout or high resolution Ice Camp lidar map.

Met City was not planned to be located straight out (ie perpendicular) from the ship but rather at 45º CCW. This would put it at about 2hr on the Ice Camp map above, in or below the Fortress Area.

We need more information before the crack can be related to regional ice pack motion but so far no shearing has been seen, the floe has experienced an extensional failure, probably because "it couldn't keep up" with the rest of the regional ice pack as it moved zonally towards the islands of SZ under the influence of persistent easterly winds.

Since the freeboard is only four inches or so, someone could stick their hand in the crack and touch sea water. However it will freeze very rapidly sandwiched between two slabs of cold ice, air temperatures being irrelevant. (This happens in mountaineering when someone falls into a crevasse and is why two rope teams are imperative.)

What caused the crack?

(1) Ship photos show a full moon. That will bring out the tidal conspiracists in force. How this could come into play 500 km from land in 4000 m water at extreme polar latitude needs a quantitative exposition, in particular prediction of the crack's orientation of the crack which I expect to be more or less perpendicular to wind direction.

(2) What happens out there is floes differ greatly (ridges, edges) in the extent to which the wind can take a hold (friction). This results in a very uneven tensile stress that is not offset yet by compression of the ice pack against land. Pushing on nearby water that envelopes the periphery -- or even on sub-100% concentration ice -- is like pushing on a string. These forces are maybe 3-4 orders of magnitude more significant than tidal.

(3) The ship itself induced the crack. It is in effect a very tall pressure ridge that catches a lot of wind. It created a long wide lead of broken ice coming in -- the ship has a beam of 27 m.

The 'gale force' winds reported could have torqued the ship against the ice pack, leveraging crack formation. When the Akademic Fedorov was along side, considerable collateral impacts were seen in the adjacent still-fragile ice.

Planning documents show Mosaic is very well aware of "observer effect" issues presented by the ship itself, resupply vessels, and bunker fuel exhaust and has mitigation plans for all of them. Events like pressure ridge and lead formation are not at all unusual -- and studying them in situ is one of the reasons the PS is out there.

(4) Waves and strong swells developing over a long reach can indeed penetrate hundreds of kms into an ice pack and be highly disruptive. However that can be ruled out in this instance, even though the Polarstern did report a day or two of gales.

(5) Ocean currents can be ruled out: there are no surface here, other than what is induced by keels of ice blown by the wind. Even if independent near-surface currents did exist, they would just carry floes along rather than stress them. If at an angle to wind stress, floes would be sheared.

The twitter sites and blogs have no had spontaneous coverage to date; they are typically multiple days behind events and are largely communication promotions pitched at major media or education.

This crack was accompanied by a major oddity in the mosaic_multisensor daily drift which shows the Polarstern as having left the floe. However it appears that they were not able to obtain a fresh Sentinel image and simply re-used the one from yesterday (see identity in comparison below).

The Polarstern has not left because of the crack incident and is still moored to the floe which regionally is drifting up against Severnaya Zemlya. page 13 map
Title: Re: MOSAiC news
Post by: uniquorn on October 18, 2019, 03:47:49 PM
Today's polarview jp2->png, inverted. PS still moored. Default size showing surrounding area leads and 300% with standard unsharp mask.
Interesting that the leads are largely east/west

Where did the terrasar image come from?

edit: added a guestimate overlay of fortress image above. Those leads look quite imposing.
Title: Re: MOSAiC news
Post by: A-Team on October 18, 2019, 07:39:23 PM
Why can't we the funding public get access to terraSAR imagery?
It is being used quite a bit now at Neumayer Station in Antarctica. Provides great imagery ... though we are looking for ultra-high resolution at one spot in the Arctic Ocean; orbital coverage may have to be requested.

I found that image on the blog of R Moore, who is part of the @MOSAiCArctic field school. It did not enlarge on a click and but does  not represent the full quality available. It is 1024 x 795 and said copyrighted, though under non-commercial Fair Use Doctrine, it can be freely distributed especially if trivial changes like 180º inversion are made (new art).

The blog posting predated selection of the floe. She did not know/say that this was The Floe, that is my interpretation. As usual, no identification numbers were provided with the image so we wouldn't know what to ask for. It is better to embed ID numbers in the image or include them in the file name so they can't get separated (as in EXIF metadata).

Exif direct-to-url yielded:

Pixels Per Unit X: 2835
Pixels Per Unit Y: 2835
Pixel Units: Meters
Modify Date: 2019:10:15 01

Here that was ominously satImage_smallsize.png which could mean cropped or dumbed down in resolution or both. Sounds like it was resized down from an original 2835 x 2835 but by whom? The floe is about 100 pixels high as downloaded; in real life it is ~3500 m in this dimension. The exif meters/pxl then makes no sense.

I did not get anywhere walking back the directory to a folder that might contain a full size version, just 403's forbidden. Not sure why it is hosted at CIRES Colorado when Moore is a grad student in applied math at Utah, on the AF for six weeks. At any rate, I wrote away for the original file.


Interesting that the leads are largely east/west. Those leads look quite imposing.
That is a typical shearing pattern seen in brittle material failures. It extends some 20 multiples of the floe's width in the png posted above which is ~50 km. There is some hint that it has forked around the (thicker) selected floe. Today was a two-fer on S1B: the PS floe was caught at two times an hour and 38 minutes apart (below, green dot is Polarstern).

We need to map the opening and closing of leads over the last month, easy given a co-registered archive. Both Gimp and ImageJ are loaded with edge detectors, which is run on your image below.

Leads can open and close up overnight to the point of unrecognizability. Pressure ridges ... not sure they can be seen. Might be lighter lineations due to roughness on the scale of Sentinel-1AB which operate at 5.404 gigahertz, meaning surface roughness at the order of the 5.5 cm wavelength.

Incredibly close call with those big leads opening but they could have relieved a lot of regional ice stress. They also could have sent a lot of difficult-to-replace and mission-critical equipment down to a watery grave. (As happened on two occasions to the hovercraft party.) Or split the legs on the Met tower if 5 m to .the left. It is interesting how much ice noise they report even frozen on the floe.

Update: looks like those big leads arose as single CW torquing failure during an "attempted rotation". The wind shifted. I'll add the whole time series in a bit ... taking screenshots off saves trying to locate the Polarstern on a huge downloads.
Title: Re: MOSAiC news
Post by: uniquorn on October 18, 2019, 09:54:16 PM
Back to the buoys. Here are the drift/delivery paths of 64 iabp buoys near the Mosaic area. There are 3 more, I think, with short identifiers and a slightly different format, not shown. Some have occasional -ve entries. At some point the id number should be related to buoy type.
Current list is attached as txt file.
added meerisportal list.
Title: Re: MOSAiC news
Post by: be cause on October 19, 2019, 01:54:32 AM
The weather forecasts are becoming increasingly interesting for anything that may be Fram bound . The floe will be going with the flow at quite a pace and may be seriously challenged by wind and wave if forecasts verify . b.c.
Title: Re: MOSAiC news
Post by: A-Team on October 19, 2019, 09:05:19 PM
floe may be seriously challenged by wind and wave if forecasts verify
Right. It is the unevenness in the stress applied by the wind to the floe and vicinity that wrenches the ice around. It would not be disruptive to the Polarstern's floe if the entire ice pack were rotating uniformly unconstrained by CAA land, but it isn't.

It has not been possible so far to predict ice motion from weather forecasts; one of the goals of Mosaic is a five-day ice forecast.

The small crack that went through camp the other day was part of a much larger and potentially more damaging event. While leads can open any time of the year, the ice today has not set up enough to resist deformation.

The Polarstern did not get the worst of it in the 16-19 October event but a lot of the Mosaic experiments in the Deployed Camp will have to be moved (or reconsidered). Quite a bit of the floe appears to be rotated, stretched and rearranged as shown in the three levels of zoom. The 4th image shows the enveloping swath of 2º of latitude and even more dramatic ice ridges and fissures.

The lower part of the figure captures hourly positions of the Polarstern over 24 hours. This wild ride comes after relatively banal displacements since mooring on the floe on Oct 04.
Title: Re: MOSAiC news
Post by: A-Team on October 19, 2019, 09:15:02 PM
Here is more of a landscape view of the event. Click to play.

What happened to the buoys -- were any lost? No, all are reportingl Here it would be interesting to show locations of nearby buoys before, during and after. Since some of the 72 buoys deployed already by Mosaic are close to the Polarstern and report twice an hour, a sudden glitch in their positions would show ice mechanical failure happened catastrophically.

If the event unfolded relatively slowly over several hours or days (or if it is still ongoing in the next days), that too should show up clearly. Thus the buoy array provides a time-resolved history of the event at a finer scale possible with 1-2 daily Sentinel-1 imagery.

Buoy positions need to be plotted on top of a relevant lat,lon range on S1 imagery. A choice like 84-86, 130-134 might work for several weeks to come. Most of the buoys can sense and signal when they are in open water.

Attached are the last 227 hours the sailwx database to 19 Oct 2019 as csv. It does show some exceptional winds on the 19th and also some unexpected ship displacements post-mooring. I extracted those with a descending sort.
Title: Re: MOSAiC news
Post by: A-Team on October 19, 2019, 11:40:12 PM
I collected current positions of 69 Mosaic buoys on Oct 19th (after the event) from IADP's database. It is more tedious to collect them for Oct 16th (not done). I then subtracted buoy lat,lon from the current position of the Polarstern to obtain distances for latitude (0.1º is 11.1 km) and simple differences for longitude. The graphic captures some of the closest buoys. The full database is attached as a csv file.
Title: Re: MOSAiC news
Post by: A-Team on October 20, 2019, 05:55:55 PM
Another day or two and the Polarstern might be right back where it started from (first image). It turns out that PolarView is a full day ahead of mosaic_multisensor which will not post its map of Oct 20th until tomorrow.

We like to have the news here first: the animation (which needs a click) shows the movement over the last 18 hours. Some leads are narrowing; others may be freezing over. Note the later frame is S1A, the other is from S1B. The Polarstern's position is shown by a white star in the scene overview.

The 180 ms close-up (3x served by PolarView) shows things have not totally settled down at the floe. One has to wonder how Mosaic deals with distortions and displacements given electric and LAN cables are laid out a km or more onto the ice.

None of the images here are rotated; 135ºE is the vertical; south is up, Greenland is down. The ship voted to have north up in their maps which has unfortunate effects as the longitude changes. Sentinel 1AB images come perfectly aligned day after day; resolution and comparisons are , corrupted by rotation.

Technical note: If the 16-bit jp2 files had been used instead of 8-bit screenshots of the jpg offerings (and all the available dates since the 17th), image quality might significantly improve on enlarged floe time series.

An interesting issue arises matching contrast in images from different S1 satellites. Even if they carry the 'same' instrument, the viewing angle might be quite different and non-nadar over the floe as the 'filmstrips' show. One approach is to hold the sharper image fixed (after optimization exploiting the 16-bit) and adjust the second so that its histogram matches. This eliminates distraction arising from wildly different initial contrasts. The quickest way of doing that is using the middle slider (gamma) in Gimp's Level tool.

Ultimately, if floe surface roughness has changed between the two timestamps or if ridge reflections are taken from different orbital perspectives, the risk of artifacts remains. At some point though, given consistency between multiple scenes, Mosaic's selected floe itself must be changing.
Title: Re: MOSAiC news
Post by: uniquorn on October 20, 2019, 08:17:02 PM
First amateur attempts towards a presentation of ice deformation. Here showing 3 mosaic buoys, chosen for their roughly equilateral relative positions using iabp coordinates to 4decimal place and Polarstern rough location to only 1dp, from day 281-291(earlier today). Polarstern coords are hourly and have been duplicated to match the 30m buoy coords.
300234068222000, Meeris Pbuoy
300234068225020 listed on iabp as IT (Ice tracker)
300234068226020, Meeris Pbuoy

Deformation is most noticable during day 286-7.
Distances shown are calculated using octave mapping which appears to produce results lower than that of the haversine method possibly due to the high latitudes. Will look into fixing that.
I haven't yet found PS location to more than 1dp
Title: Re: MOSAiC news
Post by: A-Team on October 20, 2019, 09:47:31 PM
Sea Ice Gateway --> Meer-Eis-Portal -- german--> Meereisportal
Sea Ice Gateway Questions-- german --> Meereisportalfragen
Sea Ice Gateway FAQs -- german--> Meereisportalfragenklarstellungen
Sea Ice Gateway staffer -- german--> Meereisportalfragenklarstellungenverantwortliche

I haven't yet found PS location to more than 1dp
Me either. We need to write a Meereisportalfragenklarstellungenverantwortliche about that. It should be served off the buoy list and in the legend to mosaic_multisensor. The ship should know its GPS better than any buoy -- maybe by the minute, which would be very interesting for acceleration if they are truly frozen. Bandwidth is limited but not that limited.

They also know stern-to-bow azimuthal angle (~heading/bearing) very accurately. Not seen it. The other issue are the tracks of both the PS and AF as they came and went to the floe. These have left 25m wide weaknesses in the ice that may account for current or future lead re-openings. The AK (UCKZ) turned off its beacon on 27th Sept.

Sailwx is peculiar mix of units: time in base60 rather than elapsed decimal UTC like unix, base60 lat,lon instead of base10, nautical miles, knots but temperatures in ºC. Some of the buoys report in AM/PM instead of 24 hrs. Nuisance in calculating elapsed times.

Should we be converting buoy profiler depths to fathoms? Calling in data from the nearest pay phone booth to an answering machine? The problem is mariners still using rolled nautical charts.

Why is a ship's speed measured in knots? ... By the late 16th century, sailors had begun using a chip log to measure speed. In this method, knots were tied at uniform intervals in a length of rope and then one end of the rope, with a pie-slice-shape piece of wood (or “chip”) attached to it, was tossed behind the ship.

The difference between N 85°00' and N 85°01' is 1/60 of 111111 m or 1850 m. The difference between E 132°42' and E 132°43' (at 85º.00') is (haversine) 161.5 m but at 84º it is 193.7 m. So sailwx is not reporting to a consistent accuracy.

It seems like we could use hourly sailwx to update PS's position from the latest S1AB but more dp are needed than sailwx provides. We are now 16 hours past that S1A which was ~18 hours from the last mosaic_multisensor.

Sailwx reports N 85°00' E 132°42' now whereas it was at N 85°00' E 132°48' at SIA but the satellite timestamp is to the second; the PS radar reflector was not at N 85°00' but rather N 84° and change. Note that "Where is Polarstern" --> Meereis --> sailwx.

So where are they getting these mediocre numbers from? How could they know the barometric pressure and wind speed if not from the PS's meteorological report? That has even worse lat,lon precision than sailwx. And reports in "local time" rather than UTC (though that is in the csv link).

The wind has picked up to 19 knots from 140º (Novaya Sibir) which is 35.2 km/hr. The rule of thumb is ice will move at 1% of that or 35 km/hr which pencils out to 8.4 km/day or 4.% longer than the base blue arrow in the legend to mosaic_multisensor. Because of the coriolis force and boundary conditions, the ice moves at a significant offset from the wind, here more SZ-ward.
Title: Re: MOSAiC news
Post by: blumenkraft on October 20, 2019, 09:55:41 PM
Sea Ice Gateway staffer -- german--> Meereisportalfragenklarstellungenverantwortliche

Sea Ice Gateway FAQ-staffer to be precise.

And it's female. If you refer to a male one you need to add an R or an N at the end (depending on the sentence around). Which makes it a Meereisportalfragenklarstellungenverantwortlicher.

Yes, the German language is as beautiful as it is weird.
Title: Re: MOSAiC news
Post by: A-Team on October 20, 2019, 10:08:36 PM
Staff is not likely to be empowered to provide information without supervisory approval from the Meereisportalfragenklarstellungenverantwortlicheabteilungsleiter.

The PS has yoyo-ed back to N 85°00' E 132°48' where it was 18 hours ago per sailwx, despite the steady wind from the south.

Some dimensions are noted on the lead that opened up on the 17th based on the 1140 pixels between 84.6 and 84.9º which is 3/10ths of a 111 km degree of latitude.
Title: Re: MOSAiC news
Post by: uniquorn on October 20, 2019, 10:32:50 PM
Fortunately the sailwx shipdump is in decimal degrees or I'd have to run that ani again.

They've also reserved 6 decimal places but PS only uses 1 ;)
"UTC date/time","Unix UTC timestamp","lat","lon","callsign",
"2019-Oct-20 1900", 1571598000, 85.000000, 132.800000, DBLK,

The difference between N 85°00' and N 85°01' is 1/60 of 111111 m or 1850 m. The difference between E 132°42' and E 132°43' (at 85º.00') is (haversine) 161.5 m but at 84º it is 193.7 m.
Perhaps the deformation presentation would be better shown in km.

added a crop of the mosaic no overlay map, oct11-19. click to run.
Title: Re: MOSAiC news
Post by: A-Team on October 21, 2019, 12:34:44 PM
sailwx shipdump is in decimal degrees. They've also reserved 6 decimal places but PS only uses 1 ;)
Nice find. I had been going to the wrong shipdump link which forbids access. Very weird; the Akademik Fedorov was reporting their GPS lat,lon to four decimal points before they stopped transmitting, eg 72.2806, 25.6314.

Whoever in Mosaic who produces the daily red overlay of the PS position seems to have access to the four dp position and hourly data (unless it is just fanciful hand-tracing). So we know that even at northern latitudes the accuracy is still there.

Once again, PolarView is on the job with today's S1B image with the floe and ship easily seen. The overlay from sailwx then picks up where PV left off at 2:00 am and carries position and weather forward to 9:00 am (though at the useless 1 decimal). Meanwhile, the most recent PS position on mosaic multisensor is dated 5:00 am on the 19th though the acquisition date is said the 20th.

The winds are again strong from the south. The open leads have gone from black (open water or nilas) to white (frozen-over but very thin ice). These will be recurrent weaknesses throughout the winter.

Oct-04 2300, 85.1, 134.0
Oct-21 0900, 85.1, 132.7
Polarstern net drift to date: 12.4 km
Planned drift to Svalbard: 1593 km so 0.8% of mission accomplished in 4.7% of year's journey.

Overall ice pack motion the last 2-3 days, as seen on OsiSaf below, has been unusual: favorable for the ship but not really characteristic of positive NAO anti-cyclonic circumpolar drift of recent winters. In fact, the last 3-4 days have seen a small ice cyclonic motion wandering towards Svalbard.

This will provide a bit of Fram export which has been entirely lacking since spring but does not represent a return to winter pattern of recent centuries (wreck of Jeanette) or (going by C14 of larch driftwood on Morris Jesup) recent millennia.

There seems to be a mystery ship out there in the thick ice well above the Fram Strait that is declining to identify itself. R/V icebreaker or a commercial oil tanker or ore carrier? Position is jumping around so perhaps it represents several ships who have turned off their call signs. It is reporting lat,lon to two decimals.

Lots of ship traffic in the West Greenland Current. The one-time MMSI transmission at 89ºN is possibly the two recreational hikers. The issuing authority FCC has never heard of MMSI # = 513212925; the US Coast Guard doesn't seem to have search.

Maritime Mobile Service Identity (MMSI) is a unique 9 digit number that is assigned to a (Digital Selective Calling) DSC radio or an AIS unit. Similar to a cell phone number, your MMSI number is your unique calling number for DSC radios or an AIS unit. The information provided when obtaining a MMSI number is transferred into the U.S. Coast Guard's national distress database for use in emergency situations. The U.S. Coast Guard assigns MMSI numbers only to vessels that meet the following criteria:

-- Used for recreation only
-- Not required by law to carry a radio
-- Do not communicate with or visit foreign ports

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Title: Re: MOSAiC news
Post by: A-Team on October 21, 2019, 03:15:52 PM
Here is the side-by-side that goes with the animation above. The bright dot is the Polarstern; the images are aligned to it. The S1B images are matched in contrast and enlarged 3x with sinc.  The AK can also be seen up against another floe on Oct 5th, not far to the south (up, not shown).

This series will be expanded to all available dates as time permits, including pre-mooring dates. That has to be done carefully in stages because the bright white dot of the Polarstern won't be there as reference point, plus the ice is very mobile earlier in the autumn. However the Sept 30th and Sept 23rd (bottom) are readily found. They are S1B and S1A respectively.

While changes are apparent over the last month in the floe selected for Mosaic, we don't know exactly what they mean on the ground nor what they portend for the future, especially for the white 'Fortress' area.
Title: Re: MOSAiC news
Post by: Niall Dollard on October 21, 2019, 09:33:49 PM

There seems to be a mystery ship out there in the thick ice well above the Fram Strait that is declining to identify itself. R/V icebreaker or a commercial oil tanker or ore carrier? Position is jumping around so perhaps it represents several ships who have turned off their call signs. It is reporting lat,lon to two decimals.

Lots of ship traffic in the West Greenland Current. The one-time MMSI transmission at 89ºN is possibly the two recreational hikers.

I wonder is that "mystery ship" the Pangaea. The boat that dropped of Mike Horn and Borge Ousland and has now made its way around north of Svalbard. Mike and Borge were dropped off on Sept 25th and are due to be collected north of Svalbard.

Title: Re: MOSAiC news
Post by: A-Team on October 21, 2019, 11:57:05 PM
They were to be dropped off at 85º. I wonder if the mystery call was an update on their progress towards the pole or reporting a major delay or emergency situation. They are not within range of Polarstern helicopters or anything else. It is -8ºC, dark. with a chilling 23 knot wind. S1AB doesn't cover the pole area; big leads may have opened and not be safe to cross. Nansen had to turn back when he ran into a huge area of ridge complexes too laborious to cross.

The ice is showing a lot of daily deformation in that area as well as Mosaic's for this late in October. The Ice Camp moved a surprising amount towards the pole (down) in the 2.5 hrs between S1A/S1B passes. The first ascat shows the last 16 days and runs faster than the two images of the floe.

The second shows 30 days to the 21st and some unexpected garlic press out M'Clure Strait and possible beginnings of Fram loss. However nothing special is happening around the pole.
Title: Re: MOSAiC news
Post by: uniquorn on October 22, 2019, 08:26:27 PM
Here attempting to show buoy locations in the immediate mosaic/polarstern area using delaunay triangulation. At some point we choose  a smaller subset of reliably reporting buoys and use the triangle data available from the code to attempt to show pressure and relaxation stresses placed on the ice by local movement. This can be done in octave using a virtual 3rd dimension (I hopethink)
Only 10hours are shown in the attached gif (click to run) over day293-4, chosen due to some activity to the north east. Labelling is problematic due to the close location of some buoys, reporting times and dropouts. Anyway, it's a rough overview for now.
A longer mp4 animation is available here,2417.msg233858.html#msg233858
Title: Re: MOSAiC news
Post by: A-Team on October 22, 2019, 09:52:10 PM
Very very nice!

Just some odds and ends...

... Looking for a nice polar stereographic graticule to overlay coordinates on daily S1 radar of the Mosaic floe, I noticed that Excel can really draw a nice one (1st graphic), even 1º labelled longitude steps if you make a column of 360 1's and then use the chart called 'radar' in the 'other' submenu of the chart menu. However it is difficult to get the diameter large enough to match that of latitude circles in mosaic multisensor.

... Some basic spreadsheet column statistics on Sailwx columns since the Polarstern moored on its floe Oct 4th (2nd graphic): max and min on lat,lon show the floe has resided in a very small box 84.8-85.2 by 131.6-136.2. The floe has wandered around some but today is practically back where it came from on Day 19. The wind rose averages to 185º with maximum sustained speed of 31.1 knots; temperatures to -12.9ºC.

update: 2019-Oct-23  midnight   85.3   130.5 (record lon)   100º  17.5 knot wind from 100º (southwest).

... In terms of plotting buoy movement over the S1 imagery, note first that an way to get daily position updates is to capture the IADP front page and sort down to the Mosaic floes (87 active now!). These only have lat,lon to two decimals which is not great.

... Gimp has a most excellent xy grid tool buried in filters > render > pattern > grid which you can set to convenient sub-multiple of the number of pixels between to latitude circles (111.111 km) to show scale in km. Taking lat,lon to r,θ to x,y buoy coords allows plotting them with a mouse 'go to' relative to the Polarstern reflector on the ice. (The inset is 3x enlarged.)

If the Polarview capture (as high res jpg) contains two longitude lines and two latitude lines symmetric about the vertical (135º), then the grid tool can be set to chop horizontal chords between vertices into equal line segments. Connect the dots gives accurate intermediate longitude lines.

-- By merging lat,lon fields from the Sailwx db into a list of appropriate urls for greenland-down Nullschool, then opening all the tabs at once in a browser, stacking whole window screenshots to get them in register, then cropping down to the info panel set to preferred units, you can rapidly compare wind, pressure and temperature at the drifting Polarstern's location at the time to GFS values there.,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300,90.0,1000/loc=131.300,85.300

2019-Oct-22 1200, 85.3, 131.2
2019-Oct-21 1200, 85.1, 132.5
2019-Oct-20 1200, 85.0, 132.7
2019-Oct-18 1200, 84.8, 133.1
2019-Oct-17 1200, 84.8, 132.9
2019-Oct-16 1200, 84.8, 133.5
2019-Oct-15 1200, 84.8, 134.3
2019-Oct-14 1200, 84.8, 134.4
2019-Oct-13 1200, 84.8, 134.8
2019-Oct-12 1200, 84.9, 135.7

Title: Re: MOSAiC news
Post by: uniquorn on October 22, 2019, 11:41:41 PM
Complete guess ;) overlaid onto with poor scaling.
Title: Re: MOSAiC news
Post by: A-Team on October 23, 2019, 12:20:12 AM
The day is coming when this will be a routine overlay, time series, strain gauge, lead and ridge detector!

What about shorter names for the buoys and color-coding by type?  Like 2019P156 (don't need the 2019 really) and blue for type SVP etc. I am seeing 7-8 types.

I cropped a bit, flipped it 180º and added a white circle around the Polarstern's position at the time S1A went over on Oct 21st.

Also attaching the latest csv for the 95 buoys that IADP is carrying for Mosaic deployments. Also the previous master list that showed Meereisportal's compilation too. Not yet brought in the latest from MEP nor made sure all the buoys are still in play and relevant.

I can scarcely believe they are flying out in helicopters in these 21 knot winds to set buoys. Maybe done earlier and just now trickling down to the buoy databases.
Title: Re: MOSAiC news
Post by: uniquorn on October 23, 2019, 12:48:35 AM
The scaling needs some work I think  :-\
Title: Re: MOSAiC news
Post by: psymmo7 on October 23, 2019, 08:51:56 AM
A-team / uniquorn thank you so much for all your hard work. It's really appreciated. Results so far - even if tweaking required - already look most impressive. Your visuals will enable the rest of us to get a real feel for the dynamics of the ice cover in the CAB.
Title: Re: MOSAiC news
Post by: NotaDenier on October 23, 2019, 10:33:16 AM
How MOSIAC selected the floe.

“Many of the best floes identified as being at least 80cm thick in satellite images have turned out to be less than half that”
Title: Re: MOSAiC news
Post by: uniquorn on October 23, 2019, 12:24:33 PM
What about shorter names for the buoys and color-coding by type?
Shorter names would be good. Run a poll for the names? Only joking, buotymcbuoytface1 isn't shorter. I'm reading straight from iabp buoy id but could easily add a friendlier name if a .csv with an alt name for all mosaic buoys came along. The next runs will be north up. I forgot about that. If the output is too inaccurate for overlay I'll start looking at projection again.

have turned out to be less than half that
Yesterday's image from   Ridged ice showing the thickness in that location.

added polarstern temperatures
Title: Re: MOSAiC news
Post by: Phil. on October 23, 2019, 02:46:09 PM
How MOSIAC selected the floe.

“Many of the best floes identified as being at least 80cm thick in satellite images have turned out to be less than half that”

Their accounts of the nature of those floes and why they gave a false thick reading is interesting.  Any thoughts on whether this would have an effect on the measurements of volume, A-team?
Title: Re: MOSAiC news
Post by: A-Team on October 23, 2019, 03:44:04 PM
I'll look at the BBC in a bit (it is dated 23 Oct but was written prior to Oct 4th docking); these reports are a big help. An earlier BBC piece also has valuable tidbits about ice thickness -- and how the Akademic Fedrorov plowed through a promising floe by mistake. I attached a map of current ship location relative to the Russian EEZ which the Polarstern is eager to avoid.

The news, blogs and tweets are scattered incoherently all over the internet and posted at irregular, unpredictable intervals:

Team ICE identified the site for the remote-controlled underwater robot on the floe. The team made a hole in the ice. The site named "oasis" will be used to measure ice thickness, light conditions, and physical and biochemical parameters. 5-part blog by M Shupe 05 Oct latest

There are definite limits to how much we can guess what is going on from Iridium buoy reports and S1AB imagery. The latter we cannot count on for the coming year as these satellites have many other users and other commitments. The floe is drifting zonally rather rapidly to the west despite (because) of the wind not blowing that way. I added East vs west is confusing in these north-down images so I remember it by thinking of the Far East. The Polarstern is planning on the Fram off Svalbard which is like 82º,0º.

We still have not determined why Sailwx is truncating lat,lon to one decimal when the buoys have GPS reporting to 4. Likely the Polarstern is doing the truncating, by an error in a setting or for some unknown purpose. (Sailwx is just a tech guy in Seattle who likes to sail Puget Sound.)

The image below would make a suitable frame for a nice graticule. PolarView has put on the red overlay on the jpgs every 4º of longitude -- this should have been 3º or 5º as 90º is not divisible by 4.

Some other bright reflectors are confusing matters. These could be installed equipment, possibly radar emitters near S1AB antenna frequencies, or other ships. The AK has turned off its beacon altogether and possibly returned to Murmansk. Three other icebreakers are also bringing logistic support at some point, notably fuel for the helicopters. Polar-6 and -7 will be flying scientists on and off though the ice is not strong enough yet to bring out the PistonBullys to plow the runway in Area 3, which has undergone significant deformation over the last ten days.

The second image shows the broader context of shocking Fram-ward ice motion the last couple of days, an overdue flash freeze in the Laptev that is not quite happening because of strong wind mixing, and continuing resilience to thickening on the icepack periphery.

Here Smos shows putative ice thinness but cannot measure it in the vicinity of the Polarstern or Mosaic buoys. Smos/Smap is no doubt a better edge product (nilas) but it has only appeared sporadically this month, most recently on the 19th. The BBC doesn't state what the Mosaic planning team was using for satellite ice thinness, perhaps IceSat2 (laser) rather than Smos (radar) and certainly not Piomas (theory).

Freeboard is so minimal that salt water has washed over the floes, depositing saline over the ice and wetting surface snow which fools radar into thinking it has located the seawater underneath the ice. These regions are thus dark (radar adsorbent) on Sentinel-1 while ridges of floe collisions are whitish because of surface roughness at the 5 cm scale of S1 wavelength.

date, time, lat, lon, wind direction, wind speed in knots
2019-Oct-23 1800  85.4 129.7   80  07.8 
2019-Oct-23 1700  85.4 129.7   90  05.8
2019-Oct-23 1600  85.4 129.7   80  09.7 
2019-Oct-23 1500  85.4 129.7   70  09.7 
2019-Oct-23 1400  85.4 129.8   80  07.8
2019-Oct-23 1300  85.4 129.8   70  13.6
2019-Oct-23 1200  85.3 129.8   70  13.6
2019-Oct-23 1100  85.3 129.9   80  15.6
2019-Oct-23 1000  85.3 129.9   70  15.6
2019-Oct-23 0900  85.3 130.0   80  17.5
2019-Oct-23 0800  85.3 130.0   80  17.5
2019-Oct-23 0700  85.3 130.1   80  17.5
23-10-2019  0635  S1B
2019-Oct-23 0600  85.3 130.1   90  17.5
2019-Oct-23 0500  85.3 130.2   90  19.4
23-10-2019  0408  S1A
2019-Oct-23 0400  85.3 130.2   90  19.4
2019-Oct-23 0300  85.3 130.3   90  19.4
2019-Oct-23 0200  85.3 130.3   90  19.4
2019-Oct-23 0100  85.3 130.4   90  17.5
2019-Oct-23 0000  85.3 130.5  100  17.5
Title: Re: MOSAiC news
Post by: uniquorn on October 23, 2019, 10:37:27 PM
It looks like I was way out with my complete guess. Here is a better attempt with fresher eyes. I ignored attempting to match a buoy to the polarstern instead concentrating on the radar spots and the graticules. The point don't quite match with all the radar spots but most are close.
Here using the polarview jpg and todays iabpbuoys at 06hrs. The gif is large but I'm reluctant to reduce quality. click to run.

A much smaller gif of buoy surface temperatures from p122-128, up to oct23
Title: Re: MOSAiC news
Post by: A-Team on October 24, 2019, 12:01:14 AM
Nice work on buoys! I didn't realize at first that it was a 2-frame animation. It looks good at the click-size. That is great to have the buoy network over a Sentinel base layer.

Compiled highlights (with edits and commentary in brackets) of the Polarstern cruise to Oct 23rd from screen scrapes of twitter, email, blogs, depts, BBC and newspapers. Too long but good to have it in one place (that won't get lost or deprecated to invisibility by google).

Most interesting information on thickness and near-loss of equipment and power line to ridging and shearing -- we knew from S1AB that things were morphing around on the selected floe but not exactly how. Is this going to get worse as time goes on, or will freezing solid help? (The too-fancy expedition web site does not allow text copying so screen shots have to be taken.)

First note a very important result  from R Kwok et a; about overall Arctic Ocean calibration of IceSat2 by simultaneous airplane lidar: measured elevations agree to within 2-4 cm. The April flights did not quite reach the Polarstern/Mosaic floe but more recent Icesat-2 orbits may have.

ICESat‐2 surface height and sea‐ice freeboard assessed with ATM lidar acquisitions from Operation IceBridge  30 Sep 2019

Matthew Shupe: : how to get all of our different apparatus installations fitted into a limited and challenging space. Frozen melt ponds are to be avoided as they are likely to melt once again next summer. Plus some melted all the way through. Hummocks are safer for most equipment; the heavy stuff goes on the outer wall of the Fortress. with the Met Hut  tucked up against a big plate of ice jutting up 2m inthe air. This may cause a drifting challenge.

We flagged a power line path out to all of the major installations. The ‘Ocean City’ type  power hubs weigh 700 kg but are moveable as they are installed on top of 3 snowboards. The 700 m road out to Met City was smoothed out with picks and shovels.They are able to log in remotely from one station to the next to fix issues that arise.

Carrying a big breaker bar to probe the ice conditions, I learned back at SHEBA that if you lightly throw such a bar down to the surface from about 10 inches up and it DOES NOT break through, the ice is safe to walk on. Deep snow at places, making walking difficult.

But inside the Fortress was actually quite appealing. Nice courtyards of flat ice surrounded by sturdy walls. Eventually we made our way to a broad valley heading out to the far end of the floe, with a gateway to exit the fortress. Heading south we found wide, open and mostly flat plains made of frozen over melt ponds (30 cm thick ice) and some older hummocks (~100 cm thick). At the southern extreme we looked out over a narrow lead of open water, perhaps 15-20m across. 

Took the ship’s helicopter over to AkF to give a lecture on “coupled system research” to the MOSAIC School.

October 16, 2019 Janek Uin, Brookhaven Lab/ARM Instrument
84° 45.440' N 133° 08.236' E

IThe ARM instruments are set up and will hopefully run smoothly for the rest of the campaign during the drift. In case of any trouble, our amazing technicians will be there to tackle any issues. Even today new cracks and pressure ridges appeared in the ice in the middle of a power line, challenging our efforts to set up our camp. We prepare ourselves for the next ARM adventure on Andoya, a Norwegian island located within the Arctic Circle.

October 5, 2019 Matt Boyer, Brookhaven Lab/ARM Instrument Mentor
85° 06.187' N, 133° 50.678' E

BBC x 2:
“With other floes we’ve encountered [data on 16 floes studied not released] we have clipped a piece off the edge with the ship to see how thick it is. A red and white two-meter stick, painted at 50cm intervals, sticks out from a lower deck to help judge how thick it is. The solid layer of blue ice in between snow on top and mushy rotten ice below [incompletely melted in summer, not newly forming], has rarely made it past 0.5 m.

The new layer [FYI from last winter not affected by past melt season] at the top can support equipment weight. The older rotten ice below [ice accretes to the bottom; this is newer than the ice above, is new ice on the floe edge meant?] is unreliable, although there is a question about whether a thicker layer of it helps or hinders refreezing during winter.

The investigated floe’s surface is level with the water that is freezing at its edges [freeboard should be 10% of total thickness if it were solid ice: Bernouli]. There is no protection or refuge. Instead, the floe merges seamlessly with the sea around it, rising in the distance to what could be a more rugged area towards the centre.

“The thing is, I’m not sure this piece of ice is even safe to walk on. That ridged area has holes and gaps. Take survival suits and floats,” says atmospheric physicist Markus Rex.

“In that ridged area there are holes and gaps,” says Rex, gesturing towards the central region. “It would be good to have those survival suits. Take flotation too.”

The Polarstern parks well away from a floe of interest so as not to damage it. A refrozen lead is covered by a thin layer of blackish-grey ice. The ship’s bridge radar augments what they can see. They don’t clip any ice off the edge with the ship to see how thick it is.

The edges of the "fortress" ice floe seem thin and waterlogged but in the distance the ice rises up and becomes thicker.

But the ship has to cut through a neighboring piece of ice instead. Large fragments bob vertically next to the hull to reveal a cross-section over 1 m. The sea ice in the region where the Mosaic mission have been searching has turned out to be much thinner than they were expecting. Floes are large but drill easily and could easily have disintegrated. [Only anecdotal data from EmBird surveys and drilling has been released]. 

Foes identified as >80cm thick from satellite images [IceSat2? Smos?] have turned out <40 cm from sled EM transects and drilling “Put that ship alongside such a floe and the first storm will press this ship right through it sideways. We budgeted to look at 20 floes,” says Rex.

The selected floe has a strong central section, with ice depths of up to 5m. It appears to have been created from several floes merging under high pressure. It appears as a luminous, bright patch in the otherwise dark grey satellite pictures the team are using. The inhomogeneous rugged jumble has drop-offs of 3m.

Beyond the fortress, there are two large flatter zones. The larger of these two [south side] appears to be made of ice typical of the region. It would allow the expedition to study what is happening to the ordinary, fast-disappearing young Arctic sea ice.

The ice around the ship started forming about 300 days ago – around two months later than the usual onset of the Arctic winter freeze. Those two months of missing freezing make a big difference, reducing the ice thickness by around half.

After two days, the floe, clearly very dynamic, has already changed. A large crack runs through the ice from west to east, almost severing about a fifth of the floe beyond the northern edge of the fortress. The floe is in a shear zone, with currents [a misunderstanding: no water currents exist in the central AO] pulling it in different directions. This section of the floe is not expected to last long.

The Polarstern moors to the fortress floe at 85ºN, 137ºE on Oct 4th but not as originally planned by gently lining the ship up to an edge but instead by ramming 500m towards the fortress. The captain wants to the ship securely embedded to get the robust mooring. “This may be one of the last years we can do this kind of expedition,” says Matt Shupe.

Some ice terms: frazil, shuga, nilas, pancake, grease, cake ice and frost flowers.

As sea water freezes, it first forms crystal discs known as frazil, eventually forms a suspension in the water known as grease ice, which creates an iridescent sheen like an oil slick. Waves and wind can compress the ice crystals together to form pancake ice that floats on the ocean surface. As these pancakes grow bigger they become cakes. On calmer seas, the frazils grow to form a continuous expanse of dark, glassy layer of ice, like a windowpane on top of a black sea. Shuga ice is slushy mess created by spongy white lumps that bob in the water.

Researchers at Russia’s AARI have been tracking ice floes for Mosaic in the Central Arctic Ocean all summer. They have been using data from several satellites[?], hoping to find those which survive the storms and melting.

Rex points out a darker oval in the image – the darker the ice appears, the thinking goes, the thicker and more robust the ice should be. The ice in the target region is looking like it will be 80cm thick, according to the data available. “We’d prefer one meter, one meter 20 (3 to 4ft) – but 80cm can work,” says Rex.

They will drift with the floe on an unpredictable path across the polar region, creeping on average from east to west through the year. But, choose a bad floe, or even a good floe in the wrong place, and the camp is at risk of collapse.

“What happened to N-ice would be really, really bad [4 forced relocations as Atlantic swells and melt broke up their floes]. We need to avoid that. A large fraction of model trajectories ends up in the N-ice area [2º north of Svalbard].

But other drift trajectories end their year’s drift stuck at the North Pole. Another gets into a danger zone off the coast of Greenland. [Floes never pile up against land in Greenland; floes never pass through the Nares Strait from their starting position.]

Another promising floe has 30 cm of compact snow over a deep layer of translucent blue ice that transitions to  brownish mushy honeycomb that easily sloughs off as sludge. However the Akademik Federov has sailed straight through it leaving a track visible on satellite. However it turned out to be only 30 or 40cm thick so worthless for an ice camp.

Re-interpretation of radar imagery: the discovery of so many thin floes lead the team to rethink satellite imagery. Previously the idea was that the thicker ice absorbs more radar signal from satellites overhead and so appear darker in the resulting image. But tests on those floes shows that this interpretation is wrong. The dark patches on the images are in fact showing something else entirely.

On the first floe, there was very little freeboard. “When you remove the snow, the surface was wet,” says Stefan Hendricks. The floe was flooded with seawater. The layer of salt water reduces the reflection of the radar back to the satellite. “Our idea is dark floes are actually the thin ones having low freeboard.”

September 29, 2019
84° 29' 44.2" N 128° 44' 12.1" E
Last couple of days were spent retrieving four Ocean Bed Seismometers that had been collecting data for the past year at the bottom of the ocean, almost 4 kilometers (2.5 miles) deep. The scientists responsible for these devices had remotely triggered their release from the ocean bed and had to find them among the ice once they surfaced. It took almost two days, but finally all four were found and hoisted on board.
Title: Re: MOSAiC news
Post by: uniquorn on October 24, 2019, 01:33:25 PM
3D delaunay deformation of a random set of buoys with no dropouts during days 293-296 (yesterday's data). The z-axis shows the change in distance between buoys over the last hour for each frame. I still need to check that the distance is related to the correct buoy but labelling is tricky. Distance is still calculated using octave mapping.
Posting this unfinished today as it may show what caused the ROV floe to detach
gif is optimised using gimp to reduce file size. Download and deoptimise to view full frame data, change speed etc
edit: forgot to scale to 580px
Title: Re: MOSAiC news
Post by: A-Team on October 24, 2019, 01:41:06 PM
The icepack continues to display quite dynamic behavior yesterday and today. Infrastructure deployed off the Polarstern will continue to be challenged by shifting ice within the selected Mosaic floe, even within the thicker Fortress area.

The top animation, at the native S1AB resolution, shows a large region of pack ice about the ship attempting to rotate CCW but experience brittle failure as a large rift opens in the upper right (north pole is down) as it shears like a left-lateral strike-slip fault right through the selected floe. 

The 3x zoom shows numerous deformations within the immediate vicinity of the Polarstern that cannot be favorable for instruments already set up. Some of these could no be replaced within the time frame of the drift.

Was the ROV rift -- so close to the PS -- set up by previous ice-weakening passages of the two icebreakers? No map has been produced of those routes as yet. Sailwx is not receiving accurate GPS coordinates. Alternatively, the PIs spoke of the Polarstern itself stressing the ice as a very large target for the wind. 'Moored' calls up an image of thick chains, mooring lines or massive ice anchors. However none of the images seem to be showing these. How frozen-in can a ship be in weak ice?

Because the ice has deteriorated so much over the years, not thickening as much because of later onset of freeze season (ie missing autumn months), expedition leaders have said this is the last possible year this drift could have been done. (Perhaps it was a few years earlier than that.)
Title: Re: MOSAiC news
Post by: gandul on October 24, 2019, 06:00:21 PM
Seems to be in a saddle point. displacement low, maximum shear deformation. That's not good
Title: Re: MOSAiC news
Post by: A-Team on October 24, 2019, 08:20:45 PM
in a saddle point. displacement low, maximum shear deformation. not good
Right. That was surprising to read that the ROV camp ice drifted back and forth repeatedly across the bow during the night. With Sentinel-1AB, there is just not that time resolution. Twice a day but with only a couple of hours separating the scenes. Today, S1A finished up its strip without quite catching the Polarstern.

Acquired: 24-10-2019 05:38:14 UTC S1B
Acquired: 24-10-2019 02:22:09 UTC S1A (not)

If someone here has the time, it would be great to download and mark up the 2x zoom below with displacement arrows and lead openings/ridge closings.

If someone here has a lot of time, it would be great to download the sailwx wind speed and direction since the Oct 4th and correlate it (or at least draw the overlay) with the blue Osisaf arrows on the daily mosaic_multisensor time series. The ice does not move in the direction of the wind but rather variably to its left (to Nansen's great puzzlement).

There are some geodesy issues being glossed over. The shear animations are co-registered to the Polarstern white dot on the radar. That involves moving one of the images over pixel by pixel rectilinearly until the dots line up. However they are at different longitudes so a rotation would be better to do before the translation. The differences are very slight and rotations degrade image quality which is not great to begin with.

Sentinel satellites go through a lot of complicated steps to produce the projected images that are archived. The position of the Polarstern relative to scene corners seems to affect local contrast and image quality. As might time of day, mixing A and B, or slabs of ice changing orientation. S1B is producing better focus ... it might have benefitted from on-board instrument improvements given the later time of its launch.

Whatever. The Mosaic ice camp is undergoing serious rearrangements. What does it mean to study the same floe for a year if it is not the same floe the next dat? (Heraclitus 2544 bce)

It looks like the wind is picking up again after some hours of lull. The higher wind speeds drive ice deformation, the stress going roughly as the cube. And this stress might be quite unevenly applied to the icepack. When the floes and interstitial ice are weak, as they are this autumn, we may well see serious further morphological changes in the Mosaic fortress tomorrow.

There are NO independent surface water currents in this part of the Arctic Ocean shearing ice. There is NO ongoing surge of water in from the Pacific. The immense Gulf Stream (WGC) flow into the AO is a thousand feet (300m) below the ice. Its murky diffuse return path in under study in Mosaic. 

The csv file attached merges today's IADP and Meereisportal buoy databases and proposes a systematic names for the buoy types. There are 87 new buoys that we know of.
Title: Re: MOSAiC news
Post by: uniquorn on October 24, 2019, 10:34:54 PM
Deformation test suggesting there is still significant movement up to 7am this morning. A few buoys reported till 10am but not really enough to run a separate subset. There are 32 in this animation.
The iabp page updates a few times a day(not sure of the exact times yet), the mosaic buoy data less often.
Title: Re: MOSAiC news
Post by: uniquorn on October 24, 2019, 11:38:26 PM
Been asleep at the wheel, whoi itp102
Last position on 2019/10/24 180047 UTC : 85.6311° N, 128.4221° E
edit: Drift will be similar to other buoys, added temperature and salinity 7-250m. (click to run) Much higher salinity at ~32.4 than we've become accustomed to seeing from the whoi buoys in the Beaufort.
Note that the temperature doesn't increase till ~75m depth

Thickness at 85.79N only 0.7m. IMB at same location

ITP102 was deployed on a 0.7 m thick ice floe in the Transpolar Drift on October 10, 2019 at 85° 7.9 N, 135° 34.1 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB) and Seasonal ice mass balance buoy were also installed. The ITP includes a second generation prototype MAVS current sensor operating on a pattern profiling schedule including 2 one-way profiles between 7 and 760 m depth each day and SBE-37 microcat fixed at 6 m depth.

ITP111 was deployed on a 2.8 m thick ice floe in the Transpolar Drift on October 5, 2019 at 85° 1.8 N, 132° 44.5 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB), a Seasonal ice mass balance buoy, a Meteorological sled, Spectral radiometer and AWI snow buoy were also installed. The ITP is operating on a standard sampling schedule of 2 one-way profiles between 7 and 760 m depth each day.
Will look at itp111 in a few days. 2.8m thick :)
Last position on 2019/10/24 60101 UTC : 85.3098° N, 128.2632° E
Title: Re: MOSAiC news
Post by: A-Team on October 25, 2019, 12:07:16 AM
#74 above: fabulous! innovative!

Note on #75 that the 'annual' IDBP drift background (upper left) is conceptual, not really quantitative and doesn't show the last few years specifically much correlate the buoy with the current situation (which has been no export since early June, see wipneus' chart).

I am slowly scraping in the initial dates of deployment and lat,lon for the buoys in IABP but not (yet?) in Meereis. Slowly because they use day number instead of day.month.year like Meereis which itself is dumb because it does not sort chronologically. The ones below uses

Still checking on what these SIMB3 buoys have to do with IABP and Meereis. The first four are important because they are part of Mosaic and measure snow + ice thickness (such as it is). The IMEI are a bit short and do not correspond to anything in the other two databases.

2019.10.05  IMEI:386850  SIMB3.01  Mosaic #1  85.3473   127.513   Sno+Ice  1.23m Oct 24
2019.10.09  IMEI:384820  SIMB3.02  MOSAiC #2  85.6347   128.324   Sno+Ice  0.33m Oct 24
2019.10.06  IMEI:387850  SIMB3.03  MOSAIC #3  85.3520   129.636   Sno+Ice  0.83m Oct 24
2019.10.20  IMEI:382860  SIMB3.04  MOSAIC #4  85.4289   128.414   Sno+Ice  0.64m Oct 24
2019.09.19  IMEI:386840  SIMB3.05  Dartmouth  78.9455  -133.912   Sno+Ice  0.99m Oct 24

Other surface mass balance buoys currently deployed. Full updated db attached:

SIMBA      PRIC   17 10 19   84.96   130.72
SIMBA      PRIC   17 10 19   84.68   131.95
SIMBA      PRIC   17 10 19   84.67   133.76
SIMBA      PRIC   17 10 19   84.67   133.75

IMB-bio-rad      AWI   22 10 19   85.17   130.65
IMB-bio-rad      AWI   22 10 19   85.14   132.66
Title: Re: MOSAiC news
Post by: A-Team on October 25, 2019, 03:53:21 PM
Three Sentinels today but spaced quite closely in time. Together with one from yesterday, the icepack dynamics can be seen to have calmed considerable as winds remained moderate. However individual pieces of the pack are still moving independently though in a constrained manner.

What effect this is having on deployed Mosaic equipment awaits the Oct 25th report from the Polarstern but that does not speak to what S1AB are showing.

OsiSaf is showing yet another day of dramatic trans-polar drift; recall these show two days of ice movement with 3x arrows so overall exaggerate ice displacement by 6x. Consistent movement en bulk for several days is not conducive to shears or fractures as stress is evenly distributed.

The movements bear some resemblance to 2D brownian motion:

random motion of larger particles suspended on a fluid resulting from their collision with faster moving smaller particles.This pattern typically alternates random fluctuations in a particle's position inside a fluid sub-domain with a relocation to another sub-domain.

Each relocation is followed by more fluctuations within the new closed area. There exists no preferential direction of flow as in transport phenomena. More specifically, the fluid's overall linear and angular momenta remain at zero over time.

This motion is named after the botanist Robert Brown, who first described the phenomenon in 1827, while looking through a microscope at pollen [actually, starch granules inside] of the plant Clarkia pulchella [from Idaho] in water. [wiki]  myths vs reality check
Title: Re: MOSAiC news
Post by: uniquorn on October 25, 2019, 04:52:25 PM
I had to increase the distance scale on the deformation test from 0.001km to 0.0016 to avoid clipping the lower points on yesterday's buoy data. That's compression so perhaps those leads have a bit more ridging now. It doesn't look like a smooth ride but this software presentation needs some verification from a ground report.
If you have a wider angle version of the gif above a bouy overlay with some distances might be one way of verifying. (Post temporarily if very large?)
tech note: 2 buoys had dropouts so only 30buoys in this ani. Good day for gardening so no coding today.
Title: Re: MOSAiC news
Post by: Tor Bejnar on October 25, 2019, 05:22:18 PM
With people tramping 'all over' the designated floe, will it freeze thicker due to there being less snow insulation?  If they sprayed some fresh water on the snow (but not enough to create an ice rink), would that strengthen the floe 'faster'?  Or would this create cracks between ridges (without extra accumulation) and flats (with extra accumulation)?  (Who knew that people will [or will want to] do geoengineering on whatever piece of the Earth they find themselves?)

They are obviously not using solar panels for electricity. Will the ship's diesel cause noticeable particulate contamination?   
Title: Re: MOSAiC news
Post by: A-Team on October 25, 2019, 06:26:44 PM
contamination of air samples, trampling
You can see the smokestack belching bunker fuel exhaust in the all the images, including the one just above. They have to keep the generators running; I don't think propulsion is ever engaged to maintain position. Trampling: they laid out paths and reserved pristine areas.

Mitigation of 'observer effects' like these and many more are addressed in the 122-planning document. Might write Captain Schwarze with your other ideas?

If you have a wider angle version of the gif above a bouy overlay with some distances might be one way of verifying. (Post temporarily if very large?)
Oh yes, very large. From a practical standpoint, it is easiest to capture the IABP table for the 25th which shows the "latest' lat,lon and then find the smallest bounding box needed for the S1 capture, after first counting the pixels between 85º and 86º whose distance in km we know.

The drift so far has gotten out of bounds on mosaic_multisensor but if we cropped the S1 to 84-86.5º latitude by 138-124º E longitude, we would have the whole Polarstern drift to date with room to spare and hopefully capture most of the current and near-future buoy positions.

Note though that at full S1 resolution, the box 84-86º, 140-120º is 4748 x 6484 pixels. That's manageable as a grayscale but doubtful for the forum. It would be better to retain full resolution until the buoys are placed at their 4 dp precision, then crop and reduce the crop maybe 8:1. The PS' position we don't know but fortunately we can have the white dot and the exact timestamp.

That scale is shown approximately below; we could go to 1400 x 1400 for better display of buoys. The idea is, if we wait a couple weeks, the new positions will still be in the bounding box allowing net displacement arrows. The key is to start with a sharp S1 with good contrast. Replace the jpg version with the contrast adjusted jp2 (which lacks lat,lon overlay) at the end.

I have frozen today's IABP page and looked at a few data entries, one of which shows the time of last buoy report to be 297.5625 which is actually Oct 24th at 1:30 pm rather than the 25th according to . Looking at another, 298.4167 which is 10:00 am on the 25th.

It would take a fair amount of work to walk each of the 85 data pages back to a favorable and common S1 time. However we may need more than the two dp on the front page to locate the buoys accurately enough on the image. Definitely discard the outliers. Easy enough to convert columns of lat,lon to x,y and scale up to pixel coords, float the paste of buoy name, color text by type.

I am curious though where these buoys were initially placed relative to the Polarstern (but that would mean looking through a metric ton of S1AB) though we can probably get relative to ice features such as fortress-like objects in many other nearby floes by just placing them over a current S1.

It is astonishing that the Polarstern didn't document buoy placement carefully on S1 at the time (ice and snow thickness too), maybe they did but that news apparently didn't get shared with Meereisportal.

garden. weekend. code
The present-day concept of  'week-end' first arose in the industrial north of Britain in 1879 and was originally a voluntary arrangement between factory owners and workers allowing Saturday afternoon off from 2pm on in agreement that staff would be available for work sober and refreshed on Monday morning. The US did not adopt a nationwide weekend until 1940.
Title: Re: MOSAiC news
Post by: gerontocrat on October 25, 2019, 07:41:23 PM
Mitigation of 'observer effects' like these and many more are addressed in the 122-planning document. Might write Captain Schwarze with your other ideas?

Sea Ice Drift. The PolarStern itself is a great big cliff that weighs 17,600 tons and a length of 118 metres. When the wind blows., a great big heavy sail. Have they parked it where impact on the floe is minimal? Will it be trying to move when the floe is not?

I am sure they have thought about it, but they tell me that in the Arctic reality can be somewhat different from plans.
Title: Re: MOSAiC news
Post by: A-Team on October 25, 2019, 10:33:15 PM
The PolarStern itself is a great big heavy sail.
Indeed, that very risk is discussed in detail in direct quotes from the two expedition co-leaders in the two BBC articles linked and summarized just above.

They also considered in detail the 100's of km of route swaths cut in the ice by the Fedorov and Polarstern as they approached this and other floes, deployed instruments on distant floes and exhanged staff and supplies.

The co-leaders further expressed concern that the Captain had rammed the ship in too far and too fast to get nearer the Fortress. However the ship could hardly be stably moored to the 30 cm slush on the periphery.

Like everyone else, the PI's had about zero accurate information in advance about ice thickness and quality during the eight year onshore planning process. One of the big reasons for Mosaic -- and the first thing they learned on-site -- is no one knew how to interpret billion-euro radar satellite imagery.

I have a question too: how is that we have 1672 registered members and 324 current guests but cannot find a single person to step up on buoy observations and real weather data now that we finally have some data. How about 0.1% adopting a buoy class?

Arctic Ocean weather forecasts that don't assimilate any Arctic Ocean information in their initializations -- what could possibly go wrong?  Actually, a lot. Mosaic collects a great deal of half-hourly data speaking to that. But no wx people here seem to be listening.

Imagined impacts from imaginary snowpacks on guesswork ice thickness when there are 11 snow buoys and 14 IMBs reporting? The freeboard is so low that the snow is soaking wet 300 km from the nearest open waters. Utah powder at one point but what is the R value now?

In most years, 0-1 buoys are functioning unsteadily in sub-prime locations in the Arctic Ocean. This fall, over 90 and counting. They were too clustered at deployment but that will improve from  multitudinous drift trajectories.

Importantly, the buoy network will remain a coupled system of instruments. Right now I've been putting up ad hoc base layers while uniq and macid write code as dryland draws down daily buoy data for a PostgreSQL query interface  -- and that's just for co-location. We haven't gotten to coupling buoy content yet or kriging up scalar, vector and tensor meshes, much less scaling to say 9000 buoy display.
Title: Re: MOSAiC news
Post by: uniquorn on October 25, 2019, 11:28:08 PM
A regular report on polarstern temperatures and pressure would be very helpful if anyone can manage it. A comparison with gfs and ecmwf values for the same location would also be interesting.
data is here
Title: Re: MOSAiC news
Post by: JayW on October 26, 2019, 06:26:41 PM
It's too bad that the "low light" band from the VIIRS satellites seems to be suffering some issues.  It appears to pick up the lights from PS. 

58 hour loop.
Title: Re: MOSAiC news
Post by: blumenkraft on October 26, 2019, 08:11:14 PM
Holy moly that's amazing!  :o

Great find, Jay.
Title: Re: MOSAiC news
Post by: blumenkraft on October 27, 2019, 07:10:00 AM
I think this confirms it.

There are two bright spots on the 14th when the Fedorov was still there.
Title: Re: MOSAiC news
Post by: uniquorn on October 27, 2019, 04:07:17 PM
buoy location data, day296-299. Some report at 0min, some at 30min.
Some report more often but the intermediate data is not included.
Title: Re: MOSAiC news
Post by: A-Team on October 27, 2019, 09:38:20 PM
Here is today's update from 'follow-mosaic' -- the drift route to date, colored by speed in knots. Because Mosaic does not release the Polarstern's half-hourly GPS coordinates to the public except in a very broadly sense, we have only daily Sentinel scenes (the PS is the white dot on radar) by which to measure displacements.

I had to make a great many fixes to the original map. The legend is extremely dithered so speed cannot be read off accurately along the route using a color picker.

We looked for dead Mosaic buoys. They are 3 weeks in and have already lost 4 of 92 buoys. At this rate, by the end of the year they will have lost 63 buoys. Two of them are AWI's.

Scatter plots below of 86 buoys on 26 Oct 2019 relative to Polarstern daily positions per Sailwx were made possible by a very helpful free online tool called that is quite interesting for how it was coded.

IADB does a nice job of separating out Mosaic buoys that have stopped reporting (for a week or more). One was an oddity deployed at 81º/107º that only reported for 16 hours. It might have been a field test but it has not been redeployed in the sense of reporting again through Iridium. It did not record any sensor data other than lat,lon.

Are these losses from poor design, manufacturing defects, inadequate QA, sensor failure, bad batteries, inability to connect or upload data to Iridium, ill-advised placement on a floe, or just bad luck in a harsh polar environment?

The emplacement floe might been become fragmented, washed over, crushed or buried in a collision of floes, or vandalized by curious polar bears, resulting loss of buoy function.

I definitely get the sense buoys are not tested overwinter near campus but instead deployed out of the box, hoping for the best. This happens with moorings too — the one in the Bering Strait was not field tested for software loading before deployment.

I have not seen a lot curiosity over why buoys fail and how they might be made more robust. Almost all seem home-made, with no two ad hoc design the same rather than standardized manufacture. The buoy market is too small.

The two-person company that makes SIMB3 has sold a grand total of twelve. They have not responded to my query about their peculiar IMEI notation and lack of coordination with IABP or Meereisportal despite being part of Mosaic and on Iridium.

The RS Aqua GPS buoys are 11-person corporate with brick and mortar in Portsmouth, UK. They have made quite a diversity of marine sensors since the 1980's.

It is not clear that the failed GPS buoy below is theirs. The owner acronym ‘TUT’ is nowhere explained at IAPB acronyms but I was able to chase it down to Taiyuan University of Technology in China who presumably built it. This type of buoy (a TUT buoy) has a 4.5-m-long thermistor string, assembled using 150 thermistor sensors with an accuracy of 0.1 °C and vertical interval of 0.03 m. The other 9 Mosai  TUT's are still reporting.

The Polarstern could perhaps retrieve the three failed buoys by helicopter as they are still quite nearby and get at the failure mode. Mosaic has not released any information (such as ice thickness) about the floes on which they were installed. My sense is that they didn’t characterize installations initially and don’t know where those floes are now. However we could do that for them using S1 and the few days of GPS that they were able to send in.

UpTempo buoys are explained here:

UpTempO buoys are designed to measure ocean temperature in the euphotic (light-influenced) surface layer of the Polar Oceans. These relatively inexpensive ocean buoys are designed to be easily deployed in open water or sea ice – covered conditions. As sea ice thins and retreats more and more each summer, the magnitude of ocean surface warming is accelerating. Our main goal is to measure this warming.

Here are two very recent articles on current buoys and how the measure snow vs ice thicknesses and internal flow temperature gradients.

Polar Ocean Observations: A Critical Gap in the Observing System and Its Effect on Environmental Predictions From Hours to a Season  free full
GC Smith - ‎2019

"Currently, three different systems are deployed in the Arctic including the CRREL-Dartmouth IMB, the SRSL Sea Ice Mass Balance Array (SIMBA) and the TUT ice-tethered buoy developed by PRIC and TUC in China (Zuo et al., 2018). Some of the Ice-tethered platforms described in Section “Ice-Borne Observing Systems” are also equipped with SIMBA instruments.”

Discrimination algorithm and procedure of snow depth and sea ice thickness determination using measurements of the vertical ice temperature profile by the ice-tethered buoys.
Zuo, G., Dou, Y., and Lei, R. (2018).
Sensors 18:4162. doi: 10.3390/s18124162 free full
Title: Re: MOSAiC news
Post by: A-Team on October 27, 2019, 11:20:43 PM
The daily Mosaic one-paragraph blog + photo shows the 11m meteorological tower being installed near the Polarstern. That is going to provide a better quality stream of data than weather instruments on the ship's bridge that shows up in the hourly meteorological database accessible from Meereisportal. (Sailwx has the highlights.)

It is likely explained what this meteorological tower can do in the 122-page planing document for cruise PS122/leg1. However they have limited internet bandwidth and copious onboard secure data storage. We might not see anything from this tower until it surfaces at the Pangea data archive (in 2023)

Dear reader of the Polarstern weekly reports,

In this place you are used to finding the Weekly Reports from the Polarstern Expeditions. During the MOSAIC Expedition there will be no weekly reports.

Pity. Those weekly reports from past cruises were first-rate. As was the Helmholtz weekly blog on Mosaic. The last of those was posted 12 days ago.

Ok, they are busy so the nrt news situation will remain limited. Is it being censored? In my opinion, yes. First, with 3 Sentinel images per day, we can see for ourselves that the floe and Fortress are undergoing severe dynamic rearrangements almost every day, often within consecutive Sentinel orbits only 98.6 minutes apart.

Imagery biases from variable angle of approach, time of scene, instrument variation between satellites, lat/lon and temperature variation are all easily ruled out by routine controls. The morphological changes observed raise the question of what does it even mean to study the time evolution of the 'same' floe when it isn't the same floe even three weeks into the planned year (fortress rocker day2 vs day23 attached), or even hour to hour.

We've seen minimal mention of these events and no maps of Fortress changes in the 20 days that have elapsed since the fantastic but undated, no-legend laser-scanner DEM of ice camp was released on Oct 10th. Who would buy a laser range-finder that couldn't report what the ranges were?

It's one thing to set up camp but it's another to keep it set up. They've had two near misses already  with critical equipment that is all but impossible to repair on the ship or replace with one on land. How much of the year will be spent re-setting up camp; will data collection be discontinuous due to daily damage to instruments and infrastructure?

To a certain extent, this happens every year on every Arctic cruise and was expected. However this year the ice was very weak and thin, so options were very limited. I think they made the right decision with the selected floe: yes, better floes could be found farther north but these are much less likely to drift significantly. Plus re-supply becomes very problematic in deep winter.

Further, peri-polar floes don't have the refrozen melt ponds, open water in leads and freezing processes of FYI that are important to the scientific mission. Farther south was out of the question: nothing solid enough to moor on. Returning to port was out of the question; so is waiting for next year.

So apparently is reporting bad news. And we see that not just with this particular floe but in every topic in climate change. 

For us to follow Mosaic without guidance from their end, the Sentinel radar imagery and Iridium-transmitted reports from the buoys will be our best tools. The image below looks at Sentinel coverage and its extensive area of no coverage (Pole hole starts at 87.25º 165 km from NP, any longitude).

Should the buoys continue to die off, should the Polarstern drift out of Sentinel view, we will have to rely on trickle-down from the Dr. Panglosses. That's not a good idea when we're already having to tutor them on image processing and querying of massively coupled data.
Title: Re: MOSAiC news
Post by: uniquorn on October 28, 2019, 07:13:38 PM
buoy location data, 0400hrs, day297-300. Some report at 0min, some at 30min.
Some report more often but the intermediate data is not included.

nice rammb low light animations
Title: Re: MOSAiC news
Post by: A-Team on October 28, 2019, 08:02:54 PM
The first image looks at the two Sentinel images available for today, 28 Oct 2019. I've started adding Polarstern location, weather (wind direction, wind speed knots, ºC) and smiley/frown distortion icons when there is room on the image.

The other images look at the puzzling velocity kink along the Polarstern's route dated 09 Oct 19. This occurred during a period of quite subdued winds.  The odd motion of the Mosaic floe can be attributed to massive fracturing  region several hundred km to the north (down in all imagery).

As vast far-away lead systems opened and closed, the Polarstern went around in loops, experiencing almost no deformation. This will likely be the case for the local buoy network too. Action-at-a-distance thus can affect the ship's position superficially so needs to be disentangled from actual transpolar drift and deformation going on simultaneously (3x version).

In this case, the ice closer to the pole is colder, older and thicker than the recently graduated FYI at the Mosaic Ice Camp. As such, this northerly ice cannot take up tensile stress by deformation of  weak interstitial ice. Instead, brittle stress fractures occur and propagate long distances.

As the winter progresses, ice at the Polarstern's location will be become more siimilar. Rifts like those seen at 85.5º could have catastrophic effects on deployed equipment.
Title: Re: MOSAiC news
Post by: A-Team on October 29, 2019, 04:09:14 PM
According to two closely spaced S1B images of Oct 29th (02:30 - 05:46 UTC), an east-west pressure ridge or lead appeared between the Polarstern and the equipment installations in the Ice Camp fortress. This may be related to an earlier weakness that threatened the ROV camp; alternatively to icebreaker tracks during floe selection.

The event may or may not be serious; there won't be another Sentinel pass until 02:31 tomorrow. No maps of any kind have been provided. Daily Sentinel ship locations do not allow reconstruction of ship routes at sufficient resolution. Mosaic blogs and twitter sites are providing no coverage.

This is similar to what the Fram experienced when frozen in much farther south at 78º on 26 Oct 1893 (attached). Nansen blogged his expedition almost daily, unlike Mosaic. Click on the lower left ship icon to see the daily updates at about 9:00 UTC

Meanwhile the CTD cabin and 1000m winch have been installed at Ocean City. The water is 4000m deep at their location. We should not expect nrt water chemistry as work-up of samples takes quite a while. They anticipate in the planning documents to find the isotopic signature of Atlantic Waters at some depth. However we might see temperature and salinity profiles since even an unmanned buoy can send those.

It would be a good set-up for ice fishing were the bottle rack not blocking the hole. Nansen ice-fished productively (despite the Fram carrying 6 years of provisions) but found the hole froze over too quickly, jeopardizing gear. Their scientific apparatus consisted of a weighted line lowered to measure fathoms to the continental shelf.

We located the Lost Buoy of the AWI on the imagery of early October. Significant ice failures occurred in its vicinity prior to hour of signal loss but not precisely at its location. Its overall surroundings have stayed intact.

The Akademik Fedorov could be seen nearby on some dates; buoys were installed from its helicopter. The AF shut down its GPS entirely, unlike the PS which has merely dumbed it down to the minimum the German NWS will allow.

We would know more if the PS would just strap a cheap buoy and web cam on its bow or stream ship radar hourly. They are posting far less information to the internet than the average bird-feeder in the US, with less accuracy than a $150 personal weather station.
Title: Re: MOSAiC news
Post by: uniquorn on October 29, 2019, 09:30:10 PM
update on meereis Pbuoys reporting drift speed up to oct29
edit: Some buoys were lost during that animation...fixed.
Some shadow wakes showing at the beginning of the ani
Perhaps more interesting might be the accelometer_variance, (lat/lon adjusted)
Title: Re: MOSAiC news
Post by: A-Team on October 31, 2019, 05:47:09 PM
Miscellaneous news:

-- The European Space Agency seems to have killed off imaging of sea ice around the Polarstern. The two satellites were instructed by parties unknown to no longer send data to ground stations during three orbits that had been reporting 3 times daily for the last month (missing only 09.10.19).

We'll have to see what the mosaic-multisensor map series does tomorrow 01.11.19 when the Polarstern's route is updated for 31.10.19. Possibly they will switch over to TerraSAR which is german-Proprietary. Possibly S1AB did in fact continue imaging the ice but due to some glitch or new policy is not sharing it yet with PolarView at UW.

The montage below illustrates the irregularities in S1AB contrast from day to day. Three early morning orbits have been used; the Polarstern varies in where it is moored relative to nadir. However individual scenes vary wildly in contrast. When full resolution images are cropped to the immediate vicinity of the PS, local contrast has to be optimized again.

There's a quick trick to match contrasts almost exactly across all 37 images currently offered. This involves an invertible contrast contraction followed by gamma adjustment in the Level tool of gimp.

Thirty days of Sentinel radar do not lie: the chosen floe has experienced extensive regional deformation, cracking and local ridging, most recently between the Polarstern and ice camp. Because the ship is a gigantic sail, it experiences much stronger forces than flat ice around it. The original anchors pulled out and six new ones had to be manufactured in the ship's machine shop. It is a race between freezing ice slowly getting stronger and the next bout of strong winds.

Another Chinese buoy has failed but 5 new ones have surfaced at IABP:

300234068210190 PRIC 17 10 19 84.76 132.83

300234067705760   IT     AWI     31.10.19   85.81   125.75
300234067706680   IT     AWI     31.10.19   85.80   123.73
300234067707750   IT     AWI     31.10.19   85.79   121.30
300234068706290  SIMBA   PRIC    31.10.19   85.77   123.42
300234068706330  SIMBA   PRIC    31.10.19   85.78   123.45

-- Smos and Smos/Smap are continuing to update daily at their usual Bremen archives urls despite statements to the contrary from Smos/CryoSat2 expert at #343 on the freeze forum. The link provided in support goes nowhere with an opera web browser but the one below has to the latest data. The latest week of Smos/CryoSat2 is shown in the next post. has a weekly png and netCDF

Maybe nobody gave techies at Bremen the news? Smos and Smos/Smap are at their best right now because thin ice is very extensive (rather than just being on the ice edge).

The SMOS sea ice thickness data product has moved to AWI. The SMOS processing at Uni Hamburg has stopped. You can find the SMOS and the combined SMOS and CryoSat2 products here:   Both SMOS data products underestimate the thickness on average by about 50-60%.
Title: Re: MOSAiC news
Post by: A-Team on October 31, 2019, 06:10:55 PM
The image comparison below of Oct 30th to Oct 13th of ice around the Polarstern shows why it broke away from its original mooring: extensive ice dynamics. This shows two frames of the forthcoming 37 scene animation for the entire month of October.

Because the Mosaic expedition :) has not made its original laser scan of ice elevations in the Fortress area public in any meaningful way :(, only the S1AB analog can be shown as an interactive 3D model (not supported by forum). This digital elevation map assumes, somewhat wrongly, that all dark areas are flat refrozen melt ponds with minimal freeboard and that all white areas are roughened collisional ridging proportionately higher and whiter.

The green dot shows the Polarstern's position, as determined directly by its reflected radar signal (as Mosaic  :) doesn't disclose :( ship GPS coordinates as accurately as a cheap buoy). This 3D image too can be animated over the entire month.

The combined Smos/Cryosat2 image below shows the average ice thickness in the vicinity of the Polarstern to be 0.8m. No one has chased down details being reported by the ice thickness buoys such as the 4 SIMB3 in terms of ice + snow thickness and rates of growth at their current drift positions, even though the company provides convenient open-source graphed time series.

SIMB3 Direct measurement of ice mass surface and bottom position change (mass balance)  Sensor Suite

Maxbotix 7374 Downward Looking Snow Rangefinder 1mm resolution
Airmar EchoRange+ Upward Looking Underwater Rangefinder
Bruncin 192 sensor vertical temperature chain
Air Temperature Sensor (DS18B20)
Bosch BME280 Barometric Pressure Sensor
Adafruit MTK3339 GPS
Iridium SBD connectivity

The updated buoy database will be attached in the next post. It has some new buoys, some improved standardized 5-digit buoy type names, better date specification and new columns for dead buoys.
Title: Re: MOSAiC news
Post by: gerontocrat on October 31, 2019, 07:53:33 PM
A-Team has pointed out many missing or malfunctioning bits of the jigsaw that are reducing the effectiveness of the work being done by the MOSAIC project.

It might be worth contacting the German Institute directly.  I did this when level 3 GRACE-FO data for the ice sheets was slow in appearing. I got nothing from the USA, but the professor in charge at the Helmholtz Centre, Potsda, GFZ German Research Centre for Geosciences and one of his senior scientists were extremely helpful.

After all, they can only say no (or ignore you).
ps: So the Central Arctic Sea ice extent is higher than for a good many years after freezing up extremely quickly - but fractured & thin as paper? How long before some structural strength is achieved?
Title: Re: MOSAiC news
Post by: uniquorn on October 31, 2019, 10:49:07 PM
A quick screengrab of the mass balance buoys at
The other 4 can be viewed by changing the id no shown on the gif below.
The thickness legend is obscured when using chrome.
smb01-04 are mosaic, smb05 is north of CAA

Title: Re: MOSAiC news
Post by: uniquorn on November 01, 2019, 09:02:11 PM
Ascat now provides 3 images/day giving the opportunity for finer analysis of movement, though the image times (unknown) don't appear to be evenly spread.
Here we are looking at the interferometry method described here (,1259.msg143664.html#msg143664) which highlights areas that move more than others with brighter colours, those moving less tend towards grey.
The rough position of polarstern can be estimated from the ice edge and SZ, top right.

Title: Re: MOSAiC news
Post by: A-Team on November 01, 2019, 10:18:33 PM
Ascat now provides 3 images/day. Image times (unknown) don't appear to be evenly spread.

Rather complicated how the polar images are synthesized from scatterometer swaths. And hard to track down timestamps if indeed any are applicable. Key issue though is the order. Is it A, then B, then C (or BAC, CAB, ACB, BCA,CBA)?  The order and intervals seem to be CBA at 34 and 26 minutes separation:

 01:34  metopC  Svalbard ground station
 02:08  metopB  Svalbard ground station
 02:34  metopA  Svalbard ground station

The dates of coverage are:

  ASCATA 08-Apr-2009
  ASCATB 26-Nov-2012   
  ASCATC 08-Jun-2019

For the folks back home, those daily links are: (to convert day numbers to day.month.year)

I looked at S!B interferometry about the Polarstern since there are 3 passes in quick succession most mornings, for example Oct 30th:

S1B_EW_GRDM_1SDH_20191030T 03:11
S1B_EW_GRDM_1SDH_20191030T 04:49
S1B_EW_GRDM_1SDH_20191030T 06:27

At first, I aligned the crops to the intersection of 86º˜and 128ºE which has a red overlay on the jpg version. That reference frame proved to be so-so because the ice moved too much pixels even during hourly intervals. (The motion was uniformly northeast; there was no relative motion on this date)

The other reference frame involves aligning the bright white dot of the PS on all three images, then doing the RGB from the three grayscales. That gave a somewhat more attractive product at 3x zoom. The animation shows them in perspective and also as their interferometric. The Polarstern is on the other side of that white central hump.

One of three expected Nov 1st scene showed up belatedly on Polarview; staff is looking into why Oct 31st scenes are not available to the public but accessible to mosaic-multisensor.

Mapping pan-Arctic landfast sea ice stability using Sentinel-1 interferometry
DO Dammann et al free full

Arctic landfast sea ice has undergone substantial changes in recent decades, affecting ice stability and including potential impacts on ice travel by coastal populations and on industry ice roads. We present a novel approach for evaluating landfast sea ice stability on a pan-Arctic scale using Synthetic Aperture Radar Interferometry (InSAR).

Using Sentinel-1 images from spring 2017, we discriminate between bottomfast, stabilized, and nonstabilized landfast ice over the main marginal seas of the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, and Kara seas). This approach draws on the evaluation of relative changes in interferometric fringe patterns.

This first comprehensive assessment of Arctic bottomfast sea ice extent has revealed that most of the bottomfast sea ice is situated around river mouths and coastal shallows. The Laptev and East Siberian seas dominate the aerial extent, covering roughly 4100 and 5100 km2, respectively. These seas also contain the largest extent of stabilized and nonstabilized landfast ice, but are subject to the largest uncertainties surrounding the mapping scheme.
Even so, we demonstrate the potential for using InSAR for assessing the stability of landfast ice in several key regions around the Arctic, providing a new understanding of how stability may vary between regions. InSAR-derived stability may serve for strategic planning and tactical decision support for different uses of coastal ice.

In a case study of the Nares Strait, we demonstrate that interferograms may reveal early-warning signals for the breakup of stationary sea ice.

The 'Uptempo' style of Mosaic buoy seems very straightforward and focused on a narrow but important mission: now the upper Arctic Ocean is warming.
Title: Re: MOSAiC news
Post by: A-Team on November 02, 2019, 06:25:05 PM
The question arises as to whether the Mosaic floe being so intensively studied is typical or representative of the entire Arctic Ocean, or at least FYI in the Laptev Sea. Right now, the Polarstern and all its instruments are missing a large scale unusual event in the Laptev --  a flash freeze in which accumulating nilas has been able to solidify in the near absence of mixing winds.

The new thickness tool which combines SMOS ice thinness with Cryosat2 elevations (which comes out daily but as a rolling 7-day product) shows that most of this new ice has inconsequential freeboard, making it doubtful that it could currently support an insulating layer of dry snow. It may be a month or more before it can serve as a haul-out area for seals and walruses. Should a strong wind come up first, it might well revert to open water.

The Polarstern has currently set ice anchors in a very sheltered part of the icepack. Whenever the pack rotates or moves sideways largely as a whole, no significant internal ice stress results. Problems like ridging and opening leads only arise when the wind stress and boundary conditions cause differential forces on the ice.
Title: Re: MOSAiC news
Post by: blumenkraft on November 03, 2019, 08:45:33 AM
The World’s Largest Polar Expedition is Being Threatened by Thin Ice

Link >>
Title: Re: MOSAiC news
Post by: uniquorn on November 03, 2019, 01:07:44 PM
Static overview of mosaic Pbuoys, nov2.
Yesterday's Polarstern position to 2dp in red from
Title: Re: MOSAiC news
Post by: uniquorn on November 03, 2019, 09:58:30 PM
A longer timescale view of the mosaic buoy network building up, day275-307 (today), no projection.
Dropouts (buoy fails to report or report is not recorded) show clearly using delaunay.  A large number of buoys close to PS dropped out on day304.
Title: Re: MOSAiC news
Post by: A-Team on November 04, 2019, 03:42:15 AM
Incredible floating effect! The Polarstern buoy array is such a neat idea for extending outwards from the intensively studied Mosaic floe, too bad they hardly ever work for more than a couple weeks. Maybe just stick an iphone inside instead of all that no-good custom electronics?

Below is ice thickness according to the laser altimeter and soil moisture radar ice thinness ... the palette is monotonically proportional to ice thickness (though not linearly) so it displays more or less correctly in bump map view. Because the .nc file is provided, the data can be redisplayed in polar stereographic with one of the carefully designed linear palettes available in Panoply.

However, it appears that the Cryo2Smos project has died or gone into hibernation. Its daily archive has not been updated since the week ending Oct 30th. Only nine days of product were ever produced. Meanwhile, U Bremen continues to update smos-smap and smos alone even though these were supposedly taken away by U Hamburg/AWI.

Index of /sea_ice/product/cryosat2_smos/v202/nh/LATEST/

The surface plot (needs click) bears an uncanny resemblance to grayscale values on plain vanilla Ascat, especially that extended pocket of thick white (low salinity) mature MYI ice around the pole that has been there consistently on Ascat for many many months.

It's not quite clear why the ice above the CAA is thiner (as historically that has been the very thickest) but that is seen in multiple ice thickness products. The Polarstern (white star) is currently situated in fairly thin ice, surprisingly with thicker ice shown farther south on flanking meridians.

The ship has been moving rapidly east due to a persistent clockwise rotation of the ice pack (as seen on OsiSaf: red star within green cruise bounding wedgie). If this keeps up (it won't), the Polarstern would be home for christmas. The cruise history to date:

Lat  Lon  Day   Hour  Wind(m/s) Wind (dir)
85.9 119.7 04 11 19   12:00    9 80
85.9 119.8 04 11 19   11:00    8 80
85.9 119.9 04 11 19   10:00    8 90
85.9 119.9 04 11 19   09:00    9 90
85.9 120.0 04 11 19   08:00    9 90
85.9 120.1 04 11 19   07:00    8 90
85.9 120.1 04 11 19   06:00    8 90
85.9 120.2 04 11 19   05:00    8 90
85.9 120.2 04 11 19   04:00    9 90
85.9 120.3 04 11 19   03:00    9 90
85.9 120.4 04 11 19   02:00    9 80
85.9 120.5 04 11 19   00:00    9 90
85.9 120.6 03 11 19   23:00    9 90
85.9 120.6 03 11 19   22:00    8 90
85.9 120.7 03 11 19   21:00    9 90
85.9 120.8 03 11 19   20:00   9 100
85.9 122.2 02 11 19   20:00   5 120
85.8 122.7 01 11 19   20:00   4 160
85.8 123.2 31 10 19   20:00   5 120
85.7 124.0 30 10 19   20:00   7 100
85.7 124.9 29 10 19   20:00   7  90
85.6 125.9 28 10 19   20:00   8 100
85.5 126.7 27 10 19   20:00   7 110
85.5 127.2 26 10 19   20:00   6 120
85.5 127.7 25 10 19   20:00   4  90
85.4 128.5 24 10 19   20:00   8  90
85.4 129.6 23 10 19   20:00   4 100
85.3 130.7 22 10 19   20:00   10 100
85.2 132.2 21 10 19   20:00   12 110
85.0 132.8 20 10 19   20:00   9 190
84.9 133.2 18 10 19   20:00   11 170
84.8 133.0 17 10 19   20:00   2 220
84.8 133.3 16 10 19   20:00   5  40
84.8 134.1 15 10 19   20:00   6  50
84.8 134.4 14 10 19   20:00   4 330
84.8 134.8 13 10 19   20:00   8 340
84.9 135.4 12 10 19   20:00   4  50
84.8 135.8 11 10 19   20:00   4 290
84.9 135.3 10 10 19   20:00   6 290
84.9 135.9 09 10 19   20:00   4  80
84.9 136.2 08 10 19   20:00   6 350
85.0 135.1 07 10 19   20:00   13 270
85.1 134.0 06 10 19   20:00   5 280
85.1 133.8 05 10 19   20:00   4 270
85.1 134.1 04 10 19   20:00   7 70
Title: Re: MOSAiC news
Post by: uniquorn on November 04, 2019, 09:20:04 PM
A closer look at whoi itp102
ITP102 was deployed on a 0.7 m thick ice floe in the Transpolar Drift on October 10, 2019 at 85° 7.9 N, 135° 34.1 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB) and Seasonal ice mass balance buoy were also installed. The ITP includes a second generation prototype MAVS current sensor operating on a pattern profiling schedule including 2 one-way profiles between 7 and 760 m depth each day and SBE-37 microcat fixed at 6 m depth.
The profile contours show small changes down to 50m since the start and the microcat highlights temperature and salinity changes at 6m depth since day300. Here we are also using macid's 3d R analysis to focus on temperature down to 50m showing a small rise of up to 0.16C at ~30m.

A rise in temperature and drop in salinity  at shallow depth could imply some bottom melt but no doubt there are other reasons for these conditions in this area.
Title: Re: MOSAiC news
Post by: A-Team on November 05, 2019, 10:48:17 AM
No question, where the Polarstern originally moored was very dicey given thin weak ice and strong winds (which have since dissipated). Temperatures have been quite low but the thickening process is fairly slow.

The animation below follows this development on cryo2smos which is presumably the best of both worlds in terms of satellite thickness determination. These files are produced somewhat irregularly and require a week of Cryo2 data along with daily Smos. The latter nine frames of the animation represent the Nov 2nd differenced with the early ones back to Oct 22nd.

The Polarstern is currently at 85.9N 118.7E with winds at 32 km/hr from 50º with a temperature of -23.1ºC at 07:00 UTC on 19-11-05. The clockwise rotation of the ice pack has continued another day, resulting in more easterly longitude while staying at the same distance from the pole.

Mosaic will not be sharing their ice thickness measurements any time soon so we need to follow nearby buoys with the appropriate ice profiling instruments. At some point, a 3DxT model will be produced of the 2.3 x3.5 km floe ice and snow thickness with the help of the underwater ROV with upward looking sonar and helicopter-borne downward laser scanning.

The three Sentinel-1B images at 02:22, 04:00, and 05:38 UTC this morning have sufficient resolution to show significant motion of the Polarstern and the Mosaic ice camp. The main image uses an earth-stationary coordinate system and the inset one ship-stationary.

On the whole, the local ice pack is moving uniformly en bloc but some non-threatening ice dynamics can be seen within the floe itself, though that may be partly attributable to jumbled ice reflecting satellite beams with slightly different orbits at slightly different efficiencies.
The Polarstern has appeared in 49 S1AB images since mooring to the floe (through Nov 5th). The only omissions are Oct 9th and 31st. That offers many opportunities to control variables, such as limiting analysis to images from a particular orbit on a particular time on a particular instrument.

The 7th Mosaic-launched buoy officially died today, namely 300234068713430 CapO CTD AWI.
Title: Re: MOSAiC news
Post by: uniquorn on November 05, 2019, 03:08:25 PM
the thickening process is fairly slow
three of the mosaic mass balance buoys at indicating 30- 6073cm thickness, though that appears to include snow.
The 7th Mosaic-launched buoy officially died today, namely 300234068713430 CapO CTD AWI
Two Obuoys appear to have failed at roughly the same time, though quite different locations. The pressure data for --519770 suggesting a trauma of some kind on the19th oct. Click to run the animation of Obuoy charts provided by

Following up on the small temp/salinity changes shown by itp102 above. Here are the obouys salinity at 20m depth (--169760 10m sensor has failed). Obuoy data is collected every 10minutes, the files are around 4000 lines long today. The animation has 500 frames but is still quite small, showing a pleasing amount of detail. Red dot is PS position yesterday based on diary.
Title: Re: MOSAiC news
Post by: blumenkraft on November 05, 2019, 04:32:44 PM
There is a podcast by MOSAiC Leader Markus Rex. In German language though.

Link >>
Title: Re: MOSAiC news
Post by: A-Team on November 05, 2019, 08:55:15 PM
podcast by MOSAiC Leader Markus Rex. In German language though.
I clicked all over that page, couldn't get it to play. Is it same pre-trip interview he gave whose transcript is online?

Finally an interesting photo!

First, note the new hawsers off the bow to the ice anchors mentioned earlier. The triple is taut but the double pair in front is slack, suggesting slight ice motion. If you set some lines slack and others taut, the wind will rip your vessel loose successively.

The snow is not ankle deep, as befits the Arctic Ocean as a drier desert than the Sahara. It looks very powdery though and thus is not entirely negligible as insulation. Classical R values given in earlier post aren't the whole story because the wind, eddies and turbulent air flow can't reach the ice to take heat away. Snow flurries can be seen in the searchlight beam.

The freeboard can perhaps be estimated from the shovel blades. Note the ice already trying to grow in from the sides. The big blocks, drilled around their periphery and lifted out by the ship crane look to somewhat over a meter. The photo is on the starboard side so thus this is Fortress ice, not flanking fragile melt pond.  The hole is not locatable on the lidar altimeter map but it doesn't matter since no scale was provided for that.

Some of factoids are puzzling. Are liquid volumes normally given in tonnes? Is the Polarstern using filthy bunker fuel or something higher grade, given all the wx towers and measurements. Helicopter fuel, that has to be separate. In Greenland, that is brought in in bladders left on the ice, not pumped into the hold.

Mosaic has absolutely no idea if they will ever get any closer to the North Pole than they are now, much less if they will be within 200 km (>88ºN) for 60-90 days. Modeling of drift is completely delusional -- it amounts to a seasonal weather forecast 350 days out and a whole lot more.

Each year now is effectively one-off; under rapid Arctic change it is statistically fallacious to think 12 years of unweighted previous drifts is somehow random sampling from an underlying population whose properties can be deduced and from which reliable inferences can be drawn. The Polarstern should steer clear of the shoals of model pseudoscience.

"All models are wrong but some are useful."
Yes, but how do we know in advance which ones are useful and which ones are horribly misleading, dangerous, or even worse than wrong?
Title: Re: MOSAiC news
Post by: blumenkraft on November 05, 2019, 10:13:23 PM
Here are links to a podcast player where you can listen directly and comfortably, A-Team.

Folge 1 - vor der Abfahrt
Link >>

Folge 2 - Polarlichter, Bar-Abende und die Suche nach der geeigneten Scholle
Link >>

Folge 3 - Die richtige Eisscholle
Link >>

Folge 4 - Eiscamp, Polarnacht und Abschied von “Akademik Fedorov”
Link >>
Title: Re: MOSAiC news
Post by: uniquorn on November 05, 2019, 10:40:15 PM
A-Team's calculation of 346km from Polarstern to the pole caused me to question the automatic lat/lon kilometer axes on some of the buoy animations above. They are based on a conversion of lat/lon to utm coordinates for the PlotSvalbard mapping package. Many thanks to

   Mikko Vihtakari (2019). PlotSvalbard: PlotSvalbard - Plot
   research data from Svalbard on maps. R package version 0.8.5.

for an excellent resource.
The Universal Transverse Mercator (UTM) is a system for assigning coordinates to locations on the surface of the Earth. Like the traditional method of latitude and longitude, it is a horizontal position representation, which means it ignores altitude and treats the earth as a perfect ellipsoid. However, it differs from global latitude/longitude in that it divides earth into 60 zones and projects each to the plane as a basis for its coordinates. Specifying a location means specifying the zone and the x, y coordinate in that plane. The projection from spheroid to a UTM zone is some parameterization of the transverse Mercator projection. The parameters vary by nation or region or mapping system.

Most zones in UTM span 6 degrees of longitude, and each has a designated central meridian. The scale factor at the central meridian is specified to be 0.9996 of true scale for most UTM systems in use.

The image below from the PlotSvalbard documentation shows how the UTM distance relates to the panarctic map used in the buoy animations based on the macid code. I'll crop them off in future as they may be misleading.
Title: Re: MOSAiC news
Post by: uniquorn on November 05, 2019, 11:26:57 PM
Here we are showing the mosaic Sbuoys which measure snow-ice distance. The first animation (click to run) shows the charts kindly provided by meereisportal ( which appear to show 9 buoys with sensor1<20cm and one at over 1m.
What little I know about snow buoys comes from here,2906.msg233006.html#msg233006
These seem to work by taking four sonar measurements from above, with calibration of actual snow at time of deployment. The sonar footprint is about 10 sq meters ... necessary because the snow pack is quite variable and subject to drift accumulations (or bare ice spots).

Maybe --083129 is in a hole or close to a ridge.
The second animation showing only sensor1 and drift.

Title: Re: MOSAiC news
Post by: iwantatr8 on November 06, 2019, 01:41:32 PM

Some of factoids are puzzling. Are liquid volumes normally given in tonnes? Is the Polarstern using filthy bunker fuel or something higher grade, given all the wx towers and measurements. Helicopter fuel, that has to be separate. In Greenland, that is brought in in bladders left on the ice, not pumped into the hold.

When talking about fuel it's not unusual to talk about tonnes particularly for ships, in this case Polarstern has 4 large Diesel engines, I doubt that they will be using all of them and possibly only one for power on board,  More info at the link.

Oh and here's a picture of them.
Title: Re: MOSAiC news
Post by: blumenkraft on November 06, 2019, 05:17:14 PM
Holy son of a moly what an awesome picture. 😍
Title: Re: MOSAiC news
Post by: A-Team on November 06, 2019, 05:25:02 PM
here are links to somewhat dated podcasts by Mosaic co-leader Markus Rex
Very helpful, thx!
Only one engine burning bunker fuel for electric power while frozen-in
Would Greta Thunberg would accept a ride back to Spain on a ship that burned high sulfur MDO for a year in the pristine Arctic? Oily rag left on engine room floor --> spontaneous combustion --> sterkt forbudt i Tyskland på skip --> hopefully stowed before leaving Tromsø.
What is IMO 2020? The International Maritime Organisation (IMO) has ruled that from 1 January 2020, marine sector emissions in international waters be slashed. The marine sector will have to reduce sulphur emissions by over 80% by switching to lower sulphur fuels.
Not seeing anything in the planning documents that indicates Mosaic intends to comply. They don't think the Polarstern will be reachable even by icebreaker during midwinter leg 2.

This morning, the Polarstern drifted 74 pixels east and 4 north or 73.1 pixels at WGS84 41 meter per pixel resolution on a pair of S1B's orbitally angled at 49º and separated by 3.27 hours in timestamp with no indication of significant shifting ice (final interferometric frame of lagrangian animation). This pencils out to a speed of 22 km/day.

This measure of drift fits with the multi-day cw rotating icepack depicted by OsiSaf today. Indeed, observed ice motion has finally become the classic Beaufort arm coastal extension (not gyre) with furnished by ice above the CAA, chaos in the ESAS/Laptev/Kara, constrained circumpolar drift (not trans) centered on the Pole, with export out the Fram and SV-FJL gap.

The Polarstern is currently located at 85.9º,117.4º at 14:00 UTC which is 1298 vincenty km from the flux gate at the entrance to the Fram Strait where the voyage is meant to end after 350 days. Per google earth, again in WGS84 ellipsoid geodesics, if the current velocity of ice drift keeps up (it won't), the Polarstern will reach its destination in 59 days or on 04 Jan 2020.

(Humor alert: this simple-minded estimate is just to poke fun at Mosaic's convoluted probabilistic drift route and arrival model.
Title: Re: MOSAiC news
Post by: blumenkraft on November 06, 2019, 05:29:29 PM
Very helpful, thx!

Most welcome, sir. :)

the Polarstern will reach its destination in 59 days

That would be a bummer indeed.  :-\

öliger Lappen auf Maschinenraumboden

Pah, scientists...
Title: Re: MOSAiC news
Post by: blumenkraft on November 06, 2019, 06:06:22 PM
Somehow relevant.

What to Do if you see a Polar Bear
Title: Re: MOSAiC news
Post by: A-Team on November 06, 2019, 06:43:37 PM
That risk recedes but does not go to zero as the distance from the Polarstern to the ice edge and open leads rapidly increases. Their staged response involves flares, blasts from the ship's horn, remote guard stations, night vision goggles, trip wires, bear prints in snow, shotguns for scientists, mausers for on-duty guards and so on. The polar bears though are accomplished ambush predators that can, like grizzly bears, outrun a wolf and tear open flimsy shelters. So it is a tough call for the bridge either way, especially with multiple isolated groups responding to a tripwire flare.

Some scientific Arctic expeditions also require a rescue swimmer to accompany people walking away from the ship. It is not possible to self-rescue once bulky clothes are wet and the timeframe is very short. The guard rope around the big CTD hole (above) is unsatisfactory but then it is well-lit so close to the ship. Otherwise, they have safe walking routes established and flagged.

Ridges and leads can form very suddenly but the effect is mostly stranding. Falling through melt pond drains or thinning ice is an issue more for late spring. It's never fully safe but then a motorway is even less safe.

I have not seen mention of a laser interferometer network that would provide better guidance on regional internal ice stress and incipient deformation than the virtual buoy GPS grid that uniq has been building. In past years, we have seen massive leads open up overnight from the easternmost tip of Banks Island (a repeat boundary condition) all the way to the New Siberians, ditto from Morris Jesup. We calculated a lower bound on crack propagation of 45 km/hr.

This is more of a factor mid-winter when the ice is thick and more brittle from the cold. Right now, the very extensive new ice that has formed between the summer minimum and the Siberian shore is incapable of resisting ongoing rotational shear. So it does not participate in that now but it will later as it becomes rigid.

In the vast subject of differential equations, people have been talking for centuries about complications introduced by abstract boundary conditions. In the context of Arctic sea ice, that is meant literally: fixed land encircling the basin and constraints it imposes on ice motion.

When an irresistible force (strong winds blowing against 7.1 m sq km of ice) meets an immovable object (like Kotolny Island), something has to give. And it's not the island. Up to a point, solid ice in the Laptev will inhibit the kind of ice motion we have seen the last week. Beyond that, enormous brittle fractures will become more frequent, putting equipment, people and the Polarstern itself at some risk.

There's a golden opportunity right now because of the unusual persistence and uniformity of ice pack rotation, to determine what (possibly non-unique) arrangement of high and low pressure gives rise to it. Simplistic notions such as the signature of the NAO pressure pattern are wholly inadequate to explain what we are seeing; it will require a more synoptic view of winds and the non-intuitive response of the ice to it that was already noticed on the voyage of the Fram.

Conversely, any theory of ice pack rotation will have to explain cases when the proposed pressure pattern does not result in rotation (or in ccw rotation). Indeed, one of the stated goals of Mosaic is a predictive model 5 days out for ice motion.

This is an instance of a truly massive body rotating nearly frictionlessly like a spinning ice puck near the axis of a rapidly rotating sphere where the coriolis and centrifugal forces are strong, so is different from familiar mid latitude air cyclones and the like.

For example, if the earth were rotating clockwise as seen looking down at the north pole instead of the 4 billion years of ccw, would TransPolar Drift reverse direction? And what about the AMOC:
Title: Re: MOSAiC news
Post by: A-Team on November 07, 2019, 05:51:10 PM
Polarstern "ship time" has finally been explained (below). The policy seems odd ... so many changes when they are trying to keep people on board on regular meal and work schedules. Meanwhile  mosaic_multisensor tracking, onboard meteorology and all the buoys are all on UTC?

The first icebreaker to meet the Polarstern for resupply and personnel exchange will be the Kapitan Dranitsyn, a similarly-sized vessel at 129 × 26m that is used for AARI research, passage escort and tourism currently in Murmansk. Its call sign on sailwx is UCJP; we will be eagerly following its track through the ice and inevitable damage during docking to the Fortress floe. However it may shut off its GPS beacon like the Akademic Fedorov did or at least dumb down its location to 1 dp.

AWI launched another Mosaic buoy nearby at 85.93 118.64 on Nov 6th, the 17th of the ice-tethered IT type (IMEI -7705700). These just report position and surface air temperature. There are currently 98 Mosaic buoys of which 8 have already failed.

Today saw an uneventful continuation of the last few daysof quasi-rotational motion, ie easterly drifting longitude at constant latitude (perspective animation), though OsiSaf ice motion is starting to act up, possibly bringing in shear in the next few days.

The real craziness was in very early October just before docking and then again between Oct 18-19 when the southern part of the floe seriously rearranged itself.

Currently the Polarstern is tied up at 85.9º,116.4º at 22:00 on Nov 7th, with mild wind and cold temperatures. The farthest north the Mosaic floe has drifted is 86.0º for 15 hours on Nov 5th. From where they are now, nearing the fast lane of the circumpolar drift, it doesn't seem likely that they will ever get closer to the Pole than they were on the 5th.

Following this on the latest OsiSaf amounts to drawing a circle from the pole out to the current latitude of the ship on OsiSaf, then observing whether the nearest gridded OsiSaf ice motion vector points inward relative to the tangent. If not, the Polarstern is gaining longitude but losing latitude.
Title: Re: MOSAiC news
Post by: uniquorn on November 07, 2019, 10:11:53 PM
Some expansion, mostly on the western side during day307-8. All seems calm since then. One or more buoys failed to report day310hr11-12.
deformation test, day306-311 click to run
Title: Re: MOSAiC news
Post by: uniquorn on November 08, 2019, 11:53:32 AM
update on mosaic smb01-04 ice thickness data. (edit the imei for other buoys)
Title: Re: MOSAiC news
Post by: uniquorn on November 08, 2019, 06:17:46 PM
One of this morning's sentinel images with mosaic Pbuoy overlay.
This time using the final frame of a very large 2 frame macid animation and using further scaling and rotation to match the sentinel jpg graticule. click to run.
Title: Re: MOSAiC news
Post by: A-Team on November 08, 2019, 10:52:55 PM
Measuring along the 120º longitude between 85 and 86º gives 2712.58 pixels. On the WGS84 ellipsoid, this distance is  111682 meters.  Thus the scale on S1AB images here  is 41.17 meters per pixel or reciprocally 24.289 pixels per km.

Very nice!

Cropping down but not resizing (which omits an outlier buoy in upper right), then drawing concentric circles in 5 km radial increments out to 40 km centered on the moored Polarstern (white arrow), we see this class of buoys is somewhat unevenly distributed about the base ship and not overtly co-located with ice surface features resembling the Mosaic floe.

Three Sentinel images surfaced again today (lower left). These show moderate en bloc motion over the scene uniq used, again equal parts zonally (eastward) and  southerly meridional (motion diagonally away from the 86th parallel) that can't be inferred from the 1 dp GPS data Mosaic provides to the public.

The green inset shows interferometry of the three times in the coordinate frame of the Polarstern. The Fortress area again stands out as a dynamic area (pink blob), as does a small lead (pink diagonal, upper right). The last 20 hours had subdued winds and (considering it's the Arctic) moderate temperatures. Click to see graphic at full resolution.

  85.9  115.9 19-11-08 20:00    7  360    -21.5 1017.3
  85.9  116.3 19-11-08 00:00    5   80    -26.2 1026.1

The collection of Sentinel radar overage of the Mosaic floe now consists of 57 times over 38 dates. Thanks to sailwx, a column for unix time was added; this is needed to determine time intervals. The ship reports once an hour on the hour whereas the Sentinel scenes are timestamped to intermediate minutes appropriate to the orbit.

Using database columns, it is easy to build links to the nullschool GFS display closest to the time of the Sentinel scene, showing the Polarstern's current location as the green circle along with the data popup. The GFS comes in 3 hour increments but if the url is not one of these UTC times, the link is resolved automatically to the nearest GFS time.

What relation GFS modeled wind speed, wind direction pressure and temperatures bear to actual precision on-site measurements remains to be determined. A big part of the problem in determining how ice responds to the wind (eg, the turning angle) has been poor quality, poor resolution data, often atypical coastal.
Title: Re: MOSAiC news
Post by: A-Team on November 09, 2019, 09:02:08 PM
The photogrammetry needed to determine the lat,lon of the Polarstern more accurately than Mosaic is providing can be obtained by reading the position directly off the ship's image off Sentinel-1AB imagery (very large files a very long ways from the Pole origin of coordinates).

In terms of reducing error, the angle and distance from a convenient known location such as 86º,120º can be measured very accurately (and consistently by leaving tool end fixed while processing a whole stack of S1AB). Changing the anchor or angle by one pixel provides a measure of robustness of final calculated values.

The side-angle-side triangle computation provides arbitrary accuracy so no error arises there. One remaining issue is that S1AB are rarely on the hour, unlike buoys whose GPS positions are provided to Iridium databases to the high accuracy necessary to measure deformation.

The daily OsiSaf picture provides the best single overview of Arctic Ocean sea ice conditions; it shows sea ice concentration (open water, dodgy ice, thick ice) as well as the 48-hr ice motion. Things are a bit crazy right now in the Wrangel Island area with fragile ESS ice being pushed strongly away.

This doesn't immediately affect the Polarstern which had another day of smooth sailing almost due south. However the changing wind pattern could seriously wrench the ice pack around. Indeed on 2019-Nov-09 at 1900 UTC the ship is zig-zagging a bit west at constant 85.8 latitude so something is up.

The OsiSaf/AMSR2 template template below is easy to use. Save, open in gimp, activate the lat,lon overlay, paste in an entire Osisaf (it will automatically register itself), and autocrop by the template to discard extraneous regions.

On a throwaway layer, draw in the longitude line using the amsr 1º guidelines in Siberia. Here the trick is to continue on through the Pole until the guidelines resume in Canada -- this avoids finding the Pole pixel. Then measure the 85-86 distance and proportionately reduce for 1dp accuracy on latitude. Finally put a star at the Polarstern's position from sailwx on the OsiSaf layer. Discard amsr2 and throwaway layers, crop and resize fit for purpose. Because the product is usually saved as png, the xcf format of gimp will remain unchanged as a template for the future,
Title: Re: MOSAiC news
Post by: uniquorn on November 10, 2019, 01:37:10 PM
Relatively clear weather for the mosaic team today giving an opportunity to use worldview brightness temperature(band15,Night) Suomi NPP VIIRS. Two temperature ranges have been chosen. The first to show the large leads to the north and east. The second much narrower band is an attempt to locate the Polarstern. click to run resized
Wide band,
Narrow band,

A very good rammb animation here (,2649.msg236185.html#msg236185) of the state of the ice close to the pole by Blumenkraft 
Title: Re: MOSAiC news
Post by: Phil. on November 10, 2019, 04:57:18 PM
This doesn't immediately affect the Polarstern which had another day of smooth sailing almost due south.

Title: Re: MOSAiC news
Post by: A-Team on November 10, 2019, 10:21:59 PM
Right. It's confusing but all directions are south from the North Pole, even 'up' which we are accustomed to think of as north on maps. Today the Polarstern held its latitude (southness) at 85.8º but slipped back 0.4º to larger longitude instead of drifting towards the 0º longitude Fram as intended.

Polar coordinates are the natural choice because physics associated with rotation through the earth's axis then has a simpler description. Ditto using the sun as the center for the solar system vs epicycles. All has to do with conservation of angular momentum. Problem is, pixels on device screens are square as in x,y. Money cannot buy a monitor with r,θ wedgie pixels.

Compounding the confusion is the Polarstern voted to have north up, all the time, on all maps. So two buoys, 50 km apart, are shown with different norths. No thanks. There is a reason why 'Greenland down' is used in almost all satellite products: so you can overlay them without quality-destructive fractional rotations. Not using UTC for ship time? Another head-scratcher.

The easiest way to follow Polarstern movement is glance at the hourly lat,lon at the Polarstern's weather feed (which is mounted on a mast on the bridge):

   Lat  Long  YY-MM-DD  UTC     Wind       T(C)  N   hPa
  85.8  116.3 19-11-10 20:00    6  170    -29.3     1022.7
  85.8  116.3 19-11-10 19:00    6  170    -29.1     1022.3
  85.8  116.3 19-11-10 18:00    6  170    -29.0     1022.1
  85.8  116.2 19-11-10 17:00    5  150    -29.6     1022.1
  85.8  116.2 19-11-10 16:00    5  150    -29.5     1022.0
  85.8  116.2 19-11-10 15:00    4  150    -29.4     1022.1
  85.8  116.2 19-11-10 14:00    4  150    -29.0     1021.9
  85.8  116.1 19-11-10 12:00    4  150    -29.8     1021.9
  85.8  116.1 19-11-10 11:00    5  160    -28.8     1021.8
  85.8  116.1 19-11-10 10:00    4  120    -26.7     1021.5
  85.8  116.1 19-11-10 09:00    3  110    -26.4     1021.5
  85.8  116.1 19-11-10 08:00    3  110    -26.3     1021.1
  85.8  116.1 19-11-10 07:00    2  100    -26.2     1020.8
  85.8  116.0 19-11-10 05:00    3   50    -24.0     1020.3
  85.8  116.0 19-11-10 04:00    4   40    -25.2     1020.4
  85.8  116.0 19-11-10 03:00    5   30    -25.6     1020.2
  85.8  116.0 19-11-10 02:00    4   40    -26.3     1020.0
  85.8  115.9 19-11-10 00:00    7   20    -27.4     1019.9
  85.8  115.9 19-11-09 23:00    7   10    -28.0     1019.7
  85.8  115.9 19-11-09 22:00    6  360    -27.8     1019.6
  85.8  115.9 19-11-09 21:00    6  360    -27.9     1019.7
  85.8  115.9 19-11-09 20:00    7  360    -28.0     1019.4
Title: Re: MOSAiC news
Post by: A-Team on November 10, 2019, 10:25:12 PM
Here is some further detail on the Polarstern and ambient ice dynamics in the Mosaic project area. Winds have been mild keeping stress on the ice pack minimal but that is due to change by noon tomorrow if GFS can be believed.

The peak sustained winds of 55 km/hr corresponds to about 15 m/s in the units used by AWI above. So that is about 3x the average wind speed of the recent weeks but in terms of force on the ice, more like the cube or ~27x for wind power density (2.4 kw/m^2 maximum).

The Polarstern, the world's fanciest buoy, is also a gigantic sail. While leads have surely frozen over in the area and ice on the port side is much colder than at the Oct 5th mooring, it is also more brittle but not yet much thickened.

Very little of the floe actually has equipment such as wx towers set up on it, though power and data lines run out to the three main deployment areas. The very fanciest ARM equipment stays in six containers on the bow of the ship and makes its measurements from there.

However, the near-disaster on Oct 18-19 shows that the Mosaic floe is already preconditioned to further fracturing as nearby massive fissures freeze up but never really reach full strength again.

It's not clear what it even means to 'follow the evolution of a single floe for a year" when the Mosaic floe has already undergone multiple significant demonstrable macro rearrangements not 10% into the cruise, unrelated to classical ice thermodynamic issues such as ocean-ice-air heat transfer they came to study.

While people onboard report constant noise from grinding ice, it may not be possible in the dark to sense relatively slow deformations like those seen in consecutive Sentinel scenes. The perspective and nadir views are 3x enlargements so about 14 meters per pixel over 3 hours 16 minutes of timestamp separation today. Thus changes of a few pixels off the Fortress area, if it happens at a steady rate rather than abruptly, are at tortoise speed.

Technical note: the nullschool GFS model below picks up the baton from the most recent OsiSaf in 3 hour increments and carries it forward another 100 hours. These are easily made by stepping the Polarstern position-aware url below with keystroke k, then taking whole window screenshots to build registered layers in gimp. The numerical values are then cropped out from image duplicates and layered over the tiled-up wind graphic after adjusting text height and expanding canvas width to match the main tile size.,70.000,1350/loc=116.1,85.80
Title: Re: MOSAiC news
Post by: uniquorn on November 10, 2019, 11:48:39 PM
Perhaps that is more ridging close to the polarstern.

South? It confused me too. Not happy with the blurred buoy positions on post #219 above here is a more accurate version using a larger buoy image and one rotation. Comparing the pentangle of buoys on the 86N line with the post above they do move almost due south. Confusing.
This image should include all the meereis mosaic buoys in the small area shown that are listed here ( which reported at 0400 UTC today. Lat/Lon positions are ~8mins earlier than the image. (click for full resolution)
Title: Re: MOSAiC news
Post by: Phil. on November 11, 2019, 01:49:36 AM

Re: MOSAiC news
« Reply #224 on: Today at 10:21:59 PM »
Right. It's confusing but all directions are south from the North Pole, even 'up' which we are accustomed to think of as north on maps. Today the Polarstern held its latitude (southness) at 85.8º but slipped back 0.4º on longitude instead of drifting towards the 0º longitude Fram as intended.

So latitude stayed at 85.8º so it moved neither N or S, but its longitude increased so to my mind that means they're drifting E?
Title: Re: MOSAiC news
Post by: A-Team on November 11, 2019, 04:35:45 AM
Right. They got as far north as 86.0º. At midnight, the Polarstern is currently at 85.9  116.3 on 19-11-11 at 00:00 UTC. They got as far east as 135.8. lt's all tabulated for you in the csv attached above for the Sentinel image catalog or in nrt at the url above.

It looks from uniq's map that one of the buoys is actually on the Mosaic floe itself, on the northwest corner. Since it was closest to the Polarstern on Nov 8th, it is closest to the Polarstern now since everything is moving in lock step.

So copying out the current IABP positions of all buoys in the Arctic Ocean right now and grepping down to the 92 active Mosaic ones (just replace 'cr Moraic' by 'tab Mosaic' and sort on column G), then inserting the current PS lat, lon and sorting on lat, then lon the picture below emerges for buoy names closest to the ship. Here we need the PS position to more dp, as described a few posts above.

A very good rammb animation here of the state of the ice close to the pole by Blumenkraft,2649.msg236185.html#msg236185
Passing clouds can be cleared away by hitting the 'average' button on gimp for the 60 gif frame stack. It's interesting to see utility of WorldView satellites continuing into the winter.
Title: Re: MOSAiC news
Post by: blumenkraft on November 11, 2019, 02:06:31 PM
Passing clouds can be cleared away by hitting the 'average' button on gimp for the 60 gif frame stack. It's interesting to see utility of WorldView satellites continuing into the winter.

Wondering if there is a workflow for that. Thanks for the hint anyway, A-Team. When i find the time... ;)

In other news, according to the podcast, there is a fish cam! Anyone ever saw footage of that thing?
Title: Re: MOSAiC news
Post by: A-Team on November 11, 2019, 03:44:45 PM
fish cam? bridge radar? gps? helmholtz? cruise report? ms piggy? ROV ice bottom?
I've not even seen a still. Can you not wait until 2023 when Pangea is unblocked and papers first start appearing? Mosaic has very restrictive top-down control of  ( :) ) information, trickle-down. Just because you paid 100% of expedition costs with your taxes doesn't give you any right to know what they are doing.

Another AWI snow buoy was pronounced dead this morning by IABP, the 8th such announcement that went unannounced. This one was defective from the day of installment, hardly ever reported air or snow temperatures but worked for 26 days as a GPS buoy.

They should really let the buoys start reporting to Iridium on shipboard to see if the sensors are working rather than wasting helicopter resources deploying. Or maybe test them back in Germany? The IABP record shows they did neither.

This didn't start with Mosaic -- the Arctic buoy program has always been a joke. A thousand second-hand iPhones dropped from a plane could do better tracking ice.

The Polarstern continues to drift back and forth, up and down. From the 3 Sentinels this morning, the ship can be seen moving north along the 116.4º meridian. Displacements are unremarkable: at 126.5 pxls between the 03:11 and 06:25 which pencils out to 2.8 km in 3 hrs 14 minutes or 20.8 km per day.

Since the last S1B, the ship has moved 0.2º east while holding the same latitude 85.9. Winds predicted by GFS seem to be picking up at the ship: they are at 14 m/s now and expected to reach 15.3 m/s or 55 km/hr.

This is close to the worst winds the ship has experienced so far, back on Oct 8th winds reached 60.7 km/hr according to sailwx. The attached graphic shows the wind speed distribution; the attached csv has columns the speeds in km/hr, m/s and knots. These October winds were being called gale force at the time, fair enough:

2019-Oct-08 0600   85.0   136.0   56.9
2019-Oct-08 0500   85.0   136.0   56.9
2019-Oct-08 0400   85.0   135.9   60.7
2019-Oct-08 0300   85.0   135.8   60.7
2019-Oct-08 0200   85.0   135.7   56.9
2019-Oct-08 0100   85.0   135.6   56.9
2019-Oct-07 2300   85.0   135.3   56.9
2019-Oct-08 0600   85.0   136.0   56.9
2019-Oct-08 0500   85.0   136.0   56.9
2019-Oct-08 0400   85.0   135.9   60.7
2019-Oct-08 0300   85.0   135.8   60.7
2019-Oct-08 0200   85.0   135.7   56.9
2019-Oct-08 0100   85.0   135.6   56.9
2019-Oct-07 2300   85.0   135.3   56.9
A gale force wind can be defined as a sustained strong wind, registering between 7-10 on the Beaufort Scale, which indicates wind speeds of 50 - 102 km/h

It's not entirely clear at what height above the ice these winds are measured and modeled. Usually wx tries to get clear of surface topography but that is exactly where wind stress is applied to the ice. The Polarstern has lost 0.4º of longitude in the last 14 hours; this is interesting/confusing because it suggests a wind coming from 180º (measured at the ship) blows the ice due east.T

The 14 m/s is just barely over 50 km/hr so a few more hrs will bring them into a sustained gale force stress regime. GFS today shows the winds peaking at 54 km/hr at 03:00 UTC from 205º on the 12th and not abating until 09:00 tomorrow. The S1B's will cover the ice response quite well.

  85.9  116.7 19-11-11 15:00   16  180
  85.9  116.7 19-11-11 14:00   14  180
  85.9  116.6 19-11-11 13:00   14  180
  85.9  116.6 19-11-11 12:00   13  180 [GFS predicted this perfectly: 13.9 m/s 175º, see above]
  85.9  116.6 19-11-11 11:00   13  180
  85.9  116.5 19-11-11 10:00   11  170
  85.9  116.5 19-11-11 09:00   11  170
  85.9  116.5 19-11-11 08:00   10  170 
  85.9  116.5 19-11-11 06:00   11  170   S1B 06:27
  85.9  116.4 19-11-11 05:00   10  160
  85.9  116.4 19-11-11 04:00    8  160   S1B 04:49
  85.9  116.4 19-11-11 03:00    9  160   S1B 03:11
  85.9  116.4 19-11-11 02:00    9  180
  85.9  116.3 19-11-11 00:00    7  190

The offset is mildly confusing: the 120º is at 75.00 on Sentinel images according to gimp and imageJ angle tools as appropriate to 'Greenland down'. So the offset is 45º, meaning the 116.4 should be drawn at 71.40º towards the pole which is ten thousand pixels off the image.
Title: Re: MOSAiC news
Post by: blumenkraft on November 11, 2019, 03:58:41 PM
Can you not wait


It's a shame. I will write them!
Title: Re: MOSAiC news
Post by: A-Team on November 11, 2019, 05:40:17 PM
No question, they are putting in long hard work days on the ship. However there is large support team onshore including many idle grad students, post docs and senior ice researchers (who mostly departed on the AF because lab techs stay on to maintain instruments).

Some of what we do hear strains credulity: stable ice dynamics (the satellite is wrong), launching a giant weather balloon in gale force winds (the ship weather station is wrong) and so on.

The top priority for us is simply hourly GPS position and bearing data for the Polarstern. As measured, to 4-5 dp and tenths of a degree. Nobody goes to sea without this basic technology.
In my view, sea ice forums are not perceived as a credible threat. It is rather scientists from N-ICE2015 who pose the real danger. They would know exactly what to do with the data if there were any: process and submit journal papers, thus scooping Mosaic players before they could even get their toes thawed out. That would be a terrible tragedy that dwarfs important climate change  information that might emerge sooner. That's the mind-set behind all the secrecy.

Putting academic games aside, what will tomorrow morning's satellite show? The ice along the Polarstern's meridian is experiencing high but fairly uniform wind stress that is not conducive to dangerous shearing. However to the east and west of its latitude, the wind is minimal. This suggests strong tensile forces to the east (big leads opening) and strong compressive forces to the west (ridging, over-rafting).

The current anti-cyclone, like so many of them, is not rotating about the geographic north pole but rather the pole of inaccessibility, the reason being less oppressive boundary conditions. Starting from the Polarstern's current position, it is easy to make make wind stress transects meridionally, zonally, or radially wrt the anti-cyclone center

The first of these shows a moderate gradient along air flowlines; the second which is similar to radial shows almost no wind gradient in direction or speed. Thus locally, ice dynamics may be fairly minimal in the immediate vicinity of the Polarstern. (However effects can propagate long distances in brittle sea ice.)
Title: Re: MOSAiC news
Post by: uniquorn on November 11, 2019, 11:22:27 PM
Z axis shows the % distance change per hour of 23 Mosaic buoys, day311-315. Some different movement on day312, mostly to the north. Perhaps brittle is the right description.
edit: updated downthread
Title: Re: MOSAiC news
Post by: JayW on November 12, 2019, 12:47:59 PM
Day night band is finally updating again on the RAMMB.  And it appears they fixed the issues it was having. Edit:I believe this is 375m/pixel
Title: Re: MOSAiC news
Post by: A-Team on November 12, 2019, 02:26:30 PM
Nice way of tracking Polarstern!

The first image below brings the next frame of the time series, the 00:42 of the 12th, into Sentinel position which involves a cw rotation of 105º to bring the 130th meridian into vertical position. That is needed to extend the canvas downward so that the 86º latitude circle can be drawn. (RAMMB shows the 87.5; two latitudes must be included for the radial scale to be determined accurately.)

The image shows the Polarstern position data from sailwx and ship meteo for 00:00 and 01:00 UTC. The agreement is ok with the lights of the ship show it to be at 85.95º, 117.37º (=45.00 + 72.37 measured) versus the rounded off 86.0, 117.2 of the low accuracy GPS.

It appears that no Sentinel coverage will be provided following the sustained gale force winds; processing delays at PolarView happen but are not common. It is not possible to see down to the ice on the Rammb which is working at 700nm in the far red part of the visible spectrum. ImageJ allows color to be set by wavelength; a putative 700 nm square is included.

The nearest Sentinel for Nov 12th is well to the west of the Polarstern and is shown below only to illustrate the extensive fracturing that can occur in Arctic sea ice. The inset shows the width of an 1100 km feature (at the 41m/pxl scale of the inset) can exceed a kilometer.
Title: Re: MOSAiC news
Post by: blumenkraft on November 12, 2019, 04:21:55 PM
Well, RAMMB is already done updating. Stuck at GMT 0:42.  :'( :(
Title: Re: MOSAiC news
Post by: uniquorn on November 12, 2019, 07:01:09 PM
5 mosaic buoys on iabp have files of incorrect length today, 3 of them were in the group used recently for the deformation test. In particular, 7509680 was a nice outlier to the south east for showing distance change. It's been replaced with 6344810 a little closer in.
This animation updates the one previously upthread using tighter lat/lon and a smaller z axis, day311-316(today). As the ice thickens there is likely to be less movement.

I think some of the movement shown using this method is due to a small distance change causing the delaunay triangulation to connect the buoys in a different order which will give an inaccurate, possibly meaningless, distance change in some of the central points. Using less buoys would reduce that possibility, as would diving deeper into the code. So, probably less buoys ;)
or less animations :)  Removed

Title: Re: MOSAiC news
Post by: JayW on November 14, 2019, 11:53:35 AM
This picks up at 0:42Z on the 12th.  There's a 16 hour jump at the beginning due to no imagery available.
Click to run. Contrast boosted for detail.

Title: Re: MOSAiC news
Post by: A-Team on November 14, 2019, 03:35:33 PM
The first three images show what happened in the vicinity of the Polarstern during the gale (defined as sustained winds over 50 km/hr) that peaked at 16:00 UTC on 11 Nov 19. Some very large leads opened to the east and widened again overnight but have not impacted the Mosaic experimental area too much at this point.

The first gif has cut-outs on the Nov 11th to allow the 13th and 14th to show throught. The Polarstern is in the lower right corner of the second time series.

Three S1AB scene were taken on the 11th, none on the 12th, only a rare S1A on the 13th and a single S1B on the 14th. It is difficult to understand priorities at ESA/Copernicus. Only scenes in the sensor mode EW_GRDM_1SDH will appear on PolarView; the Copernicus portal lacks polar ordering views.

The omission on the 12th is only the 4th gap in coverage since Oct 1st during which 66 scenes have been provided. The only other tools we have are RAMMB as above, Band 31-night on Terra and Band 15 VIIRS on Suomi but these are usually plagued by cloud cover.

Heat release from the ocean to the air as visualized in passive infrared bands will only correspond approximately to active S1AB radar which is imaging something entirely different, beam return as inhibited by dielectric (salinity) but enhanced by surface roughness. The black and white stars correspond to the Polarstern's coordinates on this date.

More buoys are failing to report. The number soared to 15 as a batch of Chinese TUT buoys went offline very close to the same time for unknown reasons. These leaves 84 still working though some of those report with inexplicable and growing delays. At this rate, not a single Mosaic buoy out of a hundred will survive past 20 May 2020. These buoys are very important in extending the project's reach beyond the immediate drift of the Polarstern.

The current location is at a record northerly latitude (not quite to Nansen's 86.22 but farther than the Fram's 85.92) but the drift is again away from Svalbard. Nothing resembling the weather pattern characteristic of transpolar drift has set up yet per OsiSaf.

86.2  118.3 19-11-14 13:00    9  200    -13.8
Title: Re: MOSAiC news
Post by: blumenkraft on November 14, 2019, 06:46:33 PM
Meet Trude Hohle.

(She might have the most German name in the history of German names.  ;D)

Imagine your job is to protect your crew by spotting and scaring away polar bears... Bravery for science!
Title: Re: MOSAiC news
Post by: blumenkraft on November 14, 2019, 07:49:57 PM
RAMMB-SLIDER Day&Night vs M15 band.

Makes a good combination to show cracks in the near vicinity IMHO.

Click to play.
Title: Re: MOSAiC news
Post by: A-Team on November 15, 2019, 03:10:58 AM
Decent Suomi band 15 on Nov 13th, click to enlarge. The Polarstern is just a bit under the clouds. They still have no more than a good dusting of snow.

Not clear why PS complains so much about the cold when it is far more pleasant than Chicago at 41.9º N (where I had a pre-dawn Sunday paper route as a kid).
Title: Re: MOSAiC news
Post by: A-Team on November 15, 2019, 02:18:03 PM
The ice pack fracturing has settled down but another gale force event is in the works for GFS tomorrow. The animation below takes a look ice dynamics around the Polarstern for the last 45 days, every 5th day.

Because the longitude varies quite a bit, the images were rotated back to the original mooring latitude according to the table below, then translated (moved x,y) so that the white dots of the Polarstern emitter came into register. This has the effect of removing bulk drift to leave regional ice dynamics about the ship.

Note a fair number of local features have drifted along with the Polarstern. However significant departures from rigid body motion occur and make icepack twist about more like a rubber sheet than the brittle material it is.

The inset represents a 2.5x enlargement about the ship. While there is a fair amount of daily flection, the largest change was on the 18th when the upper smooth dark patch (south side of the Mosaic floe) slid east about 725 meters in a process still continuing the last two days.

S1A 2019 11 15 T 03:27 86.2  118.3 -15.5
S1B 2019 11 10 T 05:46 85.8  116.0 -17.0
S1B 2019 11 05 T 05:38 85.9  118.8 -15.0
S1B 2019 10 30 T 04:49 85.7  124.6  -9.2
S1B 2019 10 25 T 06:19 85.4  128.0  -5.8
S1A 2019 10 20 T 03:43 85.0  132.8  -1.0
S1B 2019 10 15 T 06:02 84.8  134.4  +0.6
S1A 2019 10 10 T 03:27 84.9  135.5  +1.7
S1B 2019 10 05 T 05:46 85.1  133.8  +0.0
Title: Re: MOSAiC news
Post by: Phil. on November 15, 2019, 02:32:42 PM
the largest change was on the 18th of October?
Title: Re: MOSAiC news
Post by: A-Team on November 15, 2019, 04:25:41 PM
the largest change was on the 18th of October?
Right. Though tomorrow's winds could bring serious troubles because of ice divergence near the Polarstern's location. The ship will be losing latitude the next 3 days as ice moves at ~30º angle to the right of the wind, so towards the NSI/Laptev/Kara/SZ.
Title: Re: MOSAiC news
Post by: Stephan on November 15, 2019, 04:50:42 PM
An interview with Markus Rex,the MOSAiC expedition leader. It was broadcasted in Deutschlandfunk just two minutes ago:
Sorry it is in German.
Title: Re: MOSAiC news
Post by: blumenkraft on November 15, 2019, 05:04:38 PM
Deutschlandfunk FTW! \o/

(having "Forschung aktuell" in my podcatcher since forever)
Title: Re: MOSAiC news
Post by: A-Team on November 15, 2019, 05:43:20 PM
This is a big improvement over the happy face absurdities from the PR dept back on shore. I am not familiar with the term Presseisrücken, perhaps what we are calling ice dynamics induced by pressure from ice movement but maybe it is a technical term for pressure ridges.

"There is no direct telephone line in this wasteland, so we wrote our questions to Professor Markus Rex, head of the MOSAiC expedition, and he sent us back his answers. So the interview you hear now is retrospective.

Nevertheless, we do our work on a very dynamic ice surface. It constantly breaks up at various points; ice pressure causes high press pressures. This is not a stable, safe surface, and many teams work out on the ice every day.

Trotzdem, wir machen unsere Arbeiten auf einer sehr dynamischen Eisoberfläche. Die reißt ständig an verschiedenen Stellen auf, es bilden sich durch Eisdrucke hohe Presseisrücken.

In the weeks that followed, we were actually plagued by many difficulties. The ice is just unstable. It is torn up several times in the thin areas of this floe. We also had to recover equipment from the water. Pressure ridges have cut and spilled our fluid lines.

[[Das Eis ist eben instabil. Es ist in den dünnen Bereichen dieser Scholle mehrfach aufgerissen. Wir mussten bereits auch Ausrüstungsgegenstände aus dem Wasser wieder bergen. Presseisrücken haben unsere Stromlinien durchschnitten und verschüttet.]]

You can only look for polar bears in the beam of the ship's searchlights and use the thermal imaging device we use on the bridge to scans the environment for polar bears, but that's also a problem, which also throws our work back again and again

... in the area of ​​our searchlights from the ship or, if we have moonlight, we also see this bizarre, extraterrestrial ice landscape around us, ice sculptures that have unfolded through the forces of ice pressure and wind, interspersed with large flat areas, planes, in between where it is usually dark when the moon shimmers over, black areas, that's what we see up here out of my window. Elongated press ridges stretch several meters high, in which the ice crumbles and crumbles under these enormous forces that we sometimes have here, forming these formations. This looks really alien if I look out the window, at least if you see anything at all."

Stefan Hendricks, a geophysicist at AWI, put up another interesting comment today to the effect they flew around "investigating" various (failed?) buoys, plus updated their surface topography map along with ice surface temperature. Below are his papers from 2019:

From ICESat to ICESat-2 via IceBridge: New Insights into a Changing Sea Ice Cover

Product User Guide: AWI CryoSat-2 Sea Ice Thickness (version 2.2)

IceBird 2019 Winter: ICESat-2 Validation Data Acquisition Report

13-years of sea ice draft observations in the Laptev Sea from moored ADCPS and ULSs

Arctic warming interrupts the Transpolar Drift

Snow depth on Arctic sea ice derived from airborne radar measurements

Retrieving sea level and freeboard in the Arctic: a review of current radar altimetry

Changing Arctic Sea-ice Thickness observed by Radar Altimetry

Impact of Sea Ice Thickness and Freeboard Products on Performance of Seasonal Forecasts

Airborne evaluation of dual-band frequency satellite radar altimetry measurements

Predicted Ice Images PRIIMA: Methodology and System Evaluation
Title: Re: MOSAiC news
Post by: blumenkraft on November 15, 2019, 05:57:46 PM

Yes, i also think they mean pressure ridges by that.
Title: Re: MOSAiC news
Post by: Tor Bejnar on November 15, 2019, 07:54:53 PM
This is a big improvement over the happy face absurdities from the PR dept back on shore. I am not familiar with the term Presseisrücken, perhaps what we are calling ice dynamics induced by pressure from ice movement but maybe it is a technical term for pressure ridges.
An internet search turns up (new to me website) (  Looks like "Presseisrücken" means "pressure ridges".
Screen print:

Title: Re: MOSAiC news
Post by: Stephan on November 15, 2019, 08:26:39 PM
As a native German speaker I can confirm this translation.
Title: Re: MOSAiC news
Post by: uniquorn on November 15, 2019, 09:58:32 PM
Mosaic Pbuoys up to nov15. Rough Polarstern position from follow mosaic ( today in red
edit: smaller buoy dots, shorter tails
edit2: bigdots longer tails
Title: Re: MOSAiC news
Post by: A-Team on November 16, 2019, 12:21:00 AM
Rough Polarstern position from follow-mosaic today in red
Follow_Mosaic seems not to known where the Polarstern has been nor where it is now nor where it is going next. The ship about to hit some serious divergence in the wind vector field which will affect the ice similarly.

Like! (like bigger dots, longer tails)

Not sure what you mean by Pbuoys. These?

300234062881930*   SVP.07   2019P16    07.10.19   84.98   134.50   SVP   UPTEMPO   AWI   11.10.19
300234062887920*   SVP.08   2019P22    07.10.19   84.76   132.21   SVP   SVPB-AWI   17.10.19
300234066080220*   SVP.09   2019P122   10.10.19   85.74   128.71   SVP   SVP   EU   21.10.19
300234066081220*   SVP.10   2019P123   07.10.19   83.83   133.05   SVP   SVP   EU   21.10.19
300234066082230*   SVP.11   2019P127   07.10.19   85.90   115.25   SVP   SVP   EU   21.10.19
300234066084230*   SVP.12   2019P126   11.10.19   85.32   125.17   SVP   SVP   EU   21.10.19
300234066085220*   SVP.13   2019P128   07.10.19   86.21   110.64   SVP   SVP   EU   21.10.19
300234066087220*   SVP.14   2019P125   11.10.19   85.61   133.38   SVP   SVP   EU   21.10.19
300234066089220*   SVP.15   2019P124   29.09.19   85.78   129.60   SVP   SVP   EU   21.10.19
300234067509680*   SVP.16   2019P88    07.10.19   85.18   132.33   SVP   IT-B   AWI   22.10.19
300234067608220*   SVP.17   2019P90    07.10.19   85.64   132.39   SVP   IT-B   AWI   22.10.19
300234067700680*   SVP.18   2019P91    07.10.19   85.40   133.78   SVP   IT-B   AWI   22.10.19
300234067700760*   SVP.19   2019P92    07.10.19   85.18   126.43   SVP   IT-B   AWI   22.10.19
300234068121990*   SVP.20   2019P188   07.10.19   84.65   134.18   SVP   IT   OSU   17.10.19
300234068123990*   SVP.21   2019P191   05.10.19   84.60   129.99   SVP   IT   OSU   17.10.19
300234068125990*   SVP.22   2019P193   05.10.19   84.71   134.16   SVP   IT   OSU   17.10.19
300234068129990*   SVP.23   2019P192   07.10.19   84.58   130.83   SVP   IT   OSU   17.10.19
300234068218450*   SVP.24   2019P152   29.09.19   84.15   124.63   SVP   SVP   PRIC   17.10.19
300234068220020*   SVP.25   2019P190   07.10.19   84.63   133.49   SVP   IT   OSU   17.10.19
300234068221000*   SVP.26   2019P189   05.10.19   84.64   130.85   SVP   IT   OSU   17.10.19
300234068222000*   SVP.27   2019P194   05.10.19   84.65   130.34   SVP   IT   OSU   17.10.19
300234068226020*   SVP.28   2019P196   07.10.19   84.94   132.28   SVP   IT   OSU   17.10.19
300234068312200*   SVP.29   2019P156   28.09.19   81.85   118.45   SVP   SVP   PRIC   17.10.19
300234068312210*   SVP.30   2019P157   26.09.19   81.08   116.74   SVP   SVP   PRIC   17.10.19
300234068316210*   SVP.31   2019P155   29.09.19   83.62   123.58   SVP   SVP   PRIC   17.10.19
300234068910590*   SVP.32   2019P200   07.10.19   84.94   133.37   SVP   IT   OSU   17.10.19
300234068910810*   SVP.33   2019P198   07.10.19   85.00   132.62   SVP   IT   OSU   17.10.19
300234068915790*   SVP.34   2019P203   07.10.19   85.01   133.16   SVP   IT   OSU   17.10.19
300234068917830*   SVP.35   2019P206   07.10.19   84.91   132.74   SVP   IT   OSU   17.10.19
Title: Re: MOSAiC news
Post by: uniquorn on November 16, 2019, 01:03:35 AM
Due to unfortunate lack of coding skills I hack macid's code ( for the Pbuoy animations which use the meereis csv format here (
All Pbuoy data is calculated but some is out of range of the animation above.
The times vary but most are valid to 15/11 0300
The followmosaic PS location (to 2 decimal places) from an unknown time is added as a rough guide.
Hopefully they will provide a time with the location at some point.
Title: Re: MOSAiC news
Post by: macid on November 16, 2019, 02:04:43 AM
There's a static array with the buoy names in the code that be quickly edited in case you want to remove some odd ones or add new, I tested with P & S Type buoys for csv format handling, both do drift speed I think.

I think the most accurate location of the PS you can get by putting a dot between the closest buoys..

*edit: checking the code, line 31 makes it only download P types, have to hack it to do others yep
Title: Re: MOSAiC news
Post by: A-Team on November 16, 2019, 03:38:23 AM
most accurate location of the PS you can get by putting a dot between the closest buoys
Good suggestion. Seemed like one of the buoys was actually fixed on the corner of the selected floe. Still, the floe is ~3000 m whereas 4 dp GPS is ~11 m.

The follow_mosaic PS location (to 2 decimal places) from an unknown time is added as a rough guide. Hopefully they will provide a time with the location at some point.
Questions should be directed to the AWI press officer. No contact information is provided however. Does that answer your question?

AWI press officer Sina Löschke will contribute to the Polarstern-blog from Bremerhaven, Germany. It is going to be her part to answer questions asked by readers and help whenever the expedition team needs a writing hand.

They are really moving. Purely zonal movement (east): 2.3 degree of longitude gained at fixed latitude 86.2 in the last 55 hours, with increasing gale force winds (14+ m/s), dropping pressure and rising temperatures:

  86.2  120.4 19-11-16 09:00   17  260     -6.0  1005.1
  86.2  120.3 19-11-16 08:00   17  260     -5.9  1004.9
  86.2  120.1 19-11-16 07:00   16  250     -6.3  1005.6
  86.2  120.0 19-11-16 06:00   15  240     -7.1  1006.2
  86.2  119.9 19-11-16 05:00   14  250     -7.8  1007.0
  86.2  119.7 19-11-16 04:00   12  240     -8.0  1007.3
  86.2  119.6 19-11-16 03:00   12  240     -7.3  1007.6
  86.2  119.5 19-11-16 02:00   12  250     -6.9  1008.0
  86.2  119.4 19-11-16 01:00   13  260     -6.9  1007.8
  86.2  119.3 19-11-16 00:00   13  250     -7.4  1008.2
  86.2  119.2 19-11-15 23:00   11  250     -8.1  1009.1
  86.2  119.1 19-11-15 22:00   10  250     -8.6  1009.2

Title: Re: MOSAiC news
Post by: be cause on November 16, 2019, 11:05:26 AM
 .. chances increase that they will get much closer to the pole .. b.c.

ps. thanks for the info flow ..
Title: Re: MOSAiC news
Post by: A-Team on November 16, 2019, 12:35:46 PM
A third Sentinel-1AB came in this morning for yesterday Nov 15th. It shows what appears to be a white pressure ridge appearing between 04:16 and 05:54 right along the axis of the Polarstern. To the west (right) a long dark lead has opened further and shifted towards the Mosaic floe.

Other instabilities can also be seen but we await today's S1AB for confirmation and further developments over the multi-day course of the cyclone which will be massively disruptive for the Mosaic floe and the equipment deployed on it. PolarView is not processing images so far today, perhaps because it is early on the weekend.

The ship added another two tenths of a longitude degree just in the last hour from gale force winds. They originally moored at 85.1, 133.8 on Oct 5th.

  86.2  120.6 19-11-16 10:00   17  260
  86.2  120.4 19-11-16 09:00   17  260
Title: Re: MOSAiC news
Post by: gerontocrat on November 16, 2019, 01:49:41 PM

So you've volunteered and lobbied like mad to be on the project - what an opportunity for a young scientist!

You've got a bit of Arctic experience - in the summer's 24 hour daylight.

But today,
- 2 months of darkness is getting to you,
- it's about -7 celsius outside, + windchill from 50 kmh wind,
- the ship is creaking and groaning,
- the ice is creaking, groaning, grinding, crack! a new lead.

The boss needs you to go on the floe to rescue some gear before it heads 4,000 metres down.
The polar guards have said the bears are a bit active today - lots of holes in the ice means a better chance of getting a seal.

Life is wonderful.

Stuff that for a game of soldiers.
Title: Re: MOSAiC news
Post by: uniquorn on November 16, 2019, 05:07:00 PM
There's a static array with the buoy names in the code that be quickly edited in case you want to remove some odd ones or add new, I tested with P & S Type buoys for csv format handling, both do drift speed I think.
Thanks macid. I download all the meereis buoys separately and copy the ones I want to see into the work file. My biggest problem is making a ~80buoy iabp animation work. The files and dates are a different format. I think/hope I'm doing ok tinkering with the meereis csv's.

As we have some significant movement at the moment here are the  meereis Pbuoys ( from nov14-16 04:30, though not all buoy data may be collected up to that time.
The animation has 54 frames, which should be 1/hr though looking at the 'brownian motion' I suspect some averaging over time for the buoys that report every 10mins or lack of pixels for an accurate representation. Running a larger scale animation may determine which it is.
I've left the red PS dot in from yesterday's position for fun ;) at 86.11N 118.52
Title: Re: MOSAiC news
Post by: uniquorn on November 16, 2019, 08:51:28 PM
Pbouys at 0600 yesterday overlaid onto polarvew jpg at 0554.
Click for full res
Title: Re: MOSAiC news
Post by: blumenkraft on November 17, 2019, 06:16:15 AM
Not quite the right direction.
Title: Re: MOSAiC news
Post by: blumenkraft on November 17, 2019, 03:31:22 PM
Looks like a crack is developing right where the Polarstern is.
Title: Re: MOSAiC news
Post by: A-Team on November 17, 2019, 03:49:28 PM
The Mosaic floe experienced only moderate ice dynamics during the record winds of Nov 16th (going by the only data of the 15th and 17th); we don't know what effect if any this had on equipment set up at the Ice Camp. Another WHOI buoy is gone; again we lack a causal attribution. Tomorrow will bring further challenging conditions with strong divergent winds.

One surprise initially was the thinness of the ice; neither satellites nor models prepared them for the fragility and thinness of the ice at the selected floe. Next, the mechanical strength of the ice (which cannot be measured remotely) was less than what they needed to plow logistics runways with the Piston Bullys -- that seems unthinkable even now.

Reporters onboard the AF noted a layer of dirty ice sloughing off the bottom of overturned floes; the trip leader spoke yesterday of porous immature ice. How should these be reported at Piomas, how do they count towards Cryosat2 freeboard or SMOS ice thinness? It doesn't work very well to idealize ice from far away because it has become quite heterogenous and very complex close up.

The third surprise has been atypical winds. There is no indication of when trans- or circumpolar winds will set up -- indeed the Fram has been running in reverse. That could change, but at this rate the Polarstern won't get very far on its expected drift. Even if it resumed, the ship won't get near the pole because an enormous impenetrable block of thick MYI ice has occupied that region for close to a year. What would move that out of the way?

It's not really clear how to compare ice dynamics year on year but leads, ridging and deformation may be worse than the expedition had anticipated, again because of seemingly deteriorating ice capacity for resisting wind stress.

I wonder how the guy wires are engineered on the two tall meteo towers. Presumably with very stout springs to take up relative ice motion, yet elasticity would leave the tower swaying in the strongest winds of the trip, 21m/s (75.6 km/hr or 47 mph) on Nov 16th. Recall early on the long crack with legs of the first tower a couple of meters away from doing the splits.

  86.1  122.2 19-11-16 20:00   16  300     -5.2
  86.1  122.1 19-11-16 19:00   16  290     -5.0   994.4
  86.1  122.0 19-11-16 18:00   19  260     -5.2   994.8
  86.1  121.8 19-11-16 17:00   19  260     -5.9   995.7
  86.2  121.6 19-11-16 16:00   20  260     -6.4   997.3
  86.2  121.5 19-11-16 15:00   21  250     -6.6   998.7
  86.2  121.3 19-11-16 14:00   20  250     -6.5  1000.2
  86.2  120.9 19-11-16 12:00   19  250     -6.7  1002.9
  86.2  120.8 19-11-16 11:00   18  250     -6.5  1003.6
  86.2  120.6 19-11-16 10:00   17  260     -6.3  1004.6
  86.2  120.4 19-11-16 09:00   17  260     -6.0  1005.1

The first animation below shows 2.6 km of en bloc motion mostly to the south in the 112 minutes between S1AB timestamps. That works out to 33.9 km/day.
Title: Re: MOSAiC news
Post by: uniquorn on November 17, 2019, 07:03:53 PM
update on drift speed of the meereis Pbuoys ( from nov14-16 ~11:30

see below
Title: Re: MOSAiC news
Post by: A-Team on November 17, 2019, 08:48:15 PM
drift speed nov14-16 ~11:30
A keeper! These are fascinating to watch. Below the whole trajectory of each buoy is shown (gimp 'stack average' + level contrast tools; often used to set minimal crop boundaries that don't miss anything).

The Polarstern will be in a very curious situation tomorrow at 15:00 utc: low wind locally but situated in an 84º turn in much higher wind stress which will result (?) in a giant lead opening along the blue band.
Title: Re: MOSAiC news
Post by: uniquorn on November 17, 2019, 11:16:44 PM
Update on the 4 SIMB buoys measuring ice thickness. Temperatures confirming the current warm spell.
Title: Re: MOSAiC news
Post by: uniquorn on November 18, 2019, 06:38:46 PM
update on drift speed of the meereis Pbuoys ( from nov14-18 ~03:30

Posting this for interest while I work out which is the wayward buoy in the middle.
Title: Re: MOSAiC news
Post by: blumenkraft on November 18, 2019, 06:49:13 PM
That looks like a slowly failing GPS, no? First, you see a delay in updating and then a failure, pinpointing it to a location in the past.
Title: Re: MOSAiC news
Post by: uniquorn on November 18, 2019, 08:13:21 PM
Possibly. Badbuoy is 2019p101_300234067705700_proc, file attached

Title: Re: MOSAiC news
Post by: macid on November 19, 2019, 03:58:54 AM
P101 went bad a month ago, 2019-10-19 19:24:00, accelerometer variance reports a whopping 7076 mystery units for the last regular report in. Accelerometers are supposed to report x y and z values but I'll imagine they're combining the outputs into a sum of accelerations on all axes, indicating a tumbling of sorts when spiking.

Polar bear ran off with it? Fell into a widening lead? Latter seems more likely, graph attached. curious wave action going on before as well. heavy winds (,2888.msg233674.html#msg233674), massive drift (,2888.msg233864.html#msg233864) may have played a role in it's demise.

After that quiet for 8 days, since then intermittent reports of ~half days, indicating poor satellite reception, which would also account for the erratic movement. GPS accuracy drops quickly when you get down to just a few sats in view.

Title: Re: MOSAiC news
Post by: Hefaistos on November 19, 2019, 10:47:23 AM
"How not to get stuck in the Arctic sea ice"
Akademik Fedorov, a Russian supply vessel to Polarstern is part of Mosaic. Now playing a difficult game in the high Arctic: trying to stay in the thickening winter sea ice without getting stuck.
Long read.
Title: Re: MOSAiC news
Post by: A-Team on November 19, 2019, 01:16:49 PM
looks like a slowly failing GPS, no? First, you see a delay in updating and then a failure, pinpointing it to a location in the past. GPS accuracy drops quickly when you get down to just a few sats in view
The cadillacs among buoys, the four Mosaic-deployed SIMB3 from Dartmouth, have columns reporting the number of GPS satellites in range, how good an Iridium signal they are getting and how often the buoy calls again if it doesn't get through at first. (They also have pitch, roll and heading but those are not currently activated.)

On average, there are 8.7 GPS satellites within range and these buoys are reporting to phenomenal accuracy, eg 85.739648, 121.329032, which is rounded off to one less decimal by IABP in tracking the 100 buoys of Mosaic.

On land, GPS accuracy greatly benefits from a local tower that supplements satellites that might not have the greatest positions. The Polarstern is moving around too much (drift, jostle, internal wave recoil) for its mast to serve as a fixed local base (see motion below for Nov 18th and 19th).

I don't believe any of the buoys carry radar reflectors or emitters that would allow them to be positioned directly on Sentinel-1AB imagery which is about 41m at PolarView at 85-86º. So there is no way of independently checking reported accuracy even at that level.

source: SIMB3_387850.csv
#gpsSats   iridium_signal   iridium_retries
8.7   4.4   0 averaged over 259 entries

They did have a battery failure on 08 Nov 191/8/19 on the L1 at the remote atmospheric flux station. This turned out to be a defective fuel cell that was no longer charging the batteries. They could not get out there on the helicopter to replace it because of low clouds. This would not be applicable to buoy battery failure: no fuel cells. Ditto polar bears chewing on deployed cables: no cables. Ditto cracks propagating under the foot of the 'swingset' supporting downward looking radiation instruments: no supporting platform for buoys.

Part of their current polar bear problem may be attributable to Mosaic passengers on the Akademik Fedorov feeding them scraps of meat to take selfies.

The Polarstern, contrary to what we have been repeatedly told, has had phenomenal internet service (100 Mbps) the entire way including at its farthest north location, thanks to a new pair of satellites. The PS does not use much Iridium, too expensive for limited bandwidth.

Kepler provides 120 Mbps uplink to Arctic via satellite broadband
by Bevin Fletcher | Nov 8, 2019 11:32am

Toronto-based Kepler Communications said that it demonstrated data rates of 38 Mbps downlink and 120 Mbps uplink aboard the German icebreaker Polarstern to a 2.4m Ku-band Very Small Aperture Terminal (VSAT). The ship is home to the international MOSAiC expedition that involves hundreds of scientists and operations crews examining the effects of climate change on the Arctic.

Kepler is providing high-bandwidth satellite connectivity from low-Earth orbit (LEO) to help the team share large data files between the vessel and shore. Kepler’s satellites are placed around 575 km from Earth, so the closer location helps significantly reduce latency compared to geostationary (GEO) satellites that are 35,000 km from Earth.

“Our Global Data Service provides a cost-effective means to transfer large data volumes that will be gathered over the course of MOSAiC,” said Mina Mitry, CEO at Kepler, in statement. “Rather than only storing data locally and analyzing once physical storage can be sent back with supply vessels, we are giving scientists the ability to continuously transfer test and housekeeping data sets. When its two polar-orbiting satellites pass over the vessel, Kepler is providing 100-times higher data speeds than would otherwise be possible”

Markus Rex said “Kepler's new Global Data Service now enables us to send back bulk data, including key data files for monitoring the status of instruments together with experts at home. This will contribute to the success of MOSAiC."

How many users 100 Mbps internet line can support?  - Quora

I have 100 Mbps internet line at my work. this supports 130 wifi access points, 400 desktops, 5000 wifi users.  My network becomes limited when more are using. Is 100 Mbps line enough?
Is an Internet speed of 100Mbps considered fast? - Quora

Yes, 100 Mbps is considered fast. If you have this connection, it will take only 8 seconds to download a 100MB file at 100 Mbps. This means streaming Netflix, YouTube TV, Hulu, and any other streaming services.
Title: Re: MOSAiC news
Post by: A-Team on November 19, 2019, 05:41:41 PM
The image below locates the four SIMB3 surface mass balance buoys relative to the Polarstern on Nov 19th. This worked out because S1B took an image at 07:00 at which time all four buoys reported with an exactly matching timestamp. Not all buoys report all the time when they should (see attached databases of quadruples and triples).

The angles and lengths of the position arrows were provided by the side-angle-side tool ( given that 86º latitude is 10843.4 pixels from the pole and the 120º longitude is at a 75º angle on Sentinel images served by PolarView.

There is plenty of opportunity for confusion here but when it is all sorted out and their locations and properties plotted over time with variable values such as ice thickness interpolated within the triangles by kriging, it could be of interest. The Polarstern is measuring many of the same things and sending the data to shore with their high bandwidth internet but is not sharing it until 2023.

Ice movement as predicted above from the GFS-envisioned cyclone resulted in cracks, leads and ridging -- some of them repeats -- and considerable agitation of the whole Mosaic floe Ice Camp as seen on Sentinel despite pushing up against its resolution.
Title: Re: MOSAiC news
Post by: uniquorn on November 19, 2019, 08:41:00 PM
update on drift speed of the meereis Pbuoys ( from nov14-19 ~04:00

I took P101 out though it's still sending data sporadically.
(see animation below)
Title: Re: MOSAiC news
Post by: blumenkraft on November 19, 2019, 09:11:18 PM
Those are super cool, Uniquorn. Although they look like sperms. (One of those 'once seen, never unseen' kind of things i guess. :P )
Title: Re: MOSAiC news
Post by: blumenkraft on November 19, 2019, 09:13:07 PM
not really seeing ice thickening at PS location on Cryo2Smos

That's disturbing.  :-\
Title: Re: MOSAiC news
Post by: Tor Bejnar on November 19, 2019, 09:28:14 PM
It's not climate change, it's all the heat from the scientists running around burning calories!  [/sarc]   ::) :o :-X
Title: Re: MOSAiC news
Post by: A-Team on November 20, 2019, 12:02:57 AM
There are quite a few impacts from the Polarstern having to run its generator engines all the time ... twitter scrapes from reporters on the AF and PS and a Science commentary piece 0

The bottom line is that it is hard to do large scale science safely and sustainably at such a remote pristine location without observer impacts. But what is the alternative: crappy models, more satellites lacking sufficient resolution, more buoys that break down in the first month, more imagery that cannot be interpreted, no real understanding of ocean-ice-atmosphere couplings or the physics behind Arctic amplification?

How do the Polarstern's impacts stack up relative to commercial shipping, say of anthracite coal being dug out of a Siberian national park today and shipped to China and India?
"The next day they told us not to throw meat over the side again to the polar bears ... The data cables would later become chew toys for the polar bears."

"I've wondered sometimes whether the #Polarstern and #AkademikFedorov could have been 1K cooler, a little less brightly lit? It felt like a lot of the heat was coming from the engines or the incinerator. But it was definitely super warm on board. Don't know about the details of the heating system."

"The Polarstern can't be shut down completely, because it must serve as the expedition's power plant, command center, and hotel—which some might call a five-star. There is a dining room that serves mouthwatering cakes every afternoon at tea time, a sauna, a swimming pool, a gym, a bar, and even small shops where you can buy sweets, tobacco, and alcohol. Although the ship is passively drifting with the ice, it will guzzle 15 tons of diesel fuel per day."

"Aboard the Polarstern at MOSAiC's start, I looked forward to seeing the North Star twinkle close to the top of the sky. But the ship floods the ice with light to enable the researchers to work safely and efficiently, creating a powerful glow that blots out the sky. I did not see a single star during my 2 weeks aboard."

The solid layer of blue ice in between snow on top and mushy rotten ice below, has rarely made it past the 50 cm gradation on the measuring stick. The new layer at the top is the firm ice that can support weight. The older rotten ice below is unreliable, although there is a question about whether a thicker layer of it helps or hinders refreezing during winter.

"For AWI biologist Allison Fong, the glow is a problem. She wants to better understand how microbial plant life survives in the Arctic winter, when there is no sunlight for months on end, but she can't study samples that have been exposed to artificial light. So, once a week she plans to drive a snowmobile to what she calls the "dark zone" hidden behind a fortress of small ridges of snow and ice some 500 meters from the ship. There, researchers will don red headlamps (red light doesn't affect most organisms) and collect ice cores that they will analyze back at the ship."

"Oceanographers, meanwhile, are dealing with the heat, turbulence, and wastewater produced by the Polarstern. "At the main site around the ship, there's sort of a dead zone" for collecting data, says Tim Stanton, an oceanographer at the Naval Postgraduate School in Monterey, California. To avoid the issue, he and others have deployed a handful of autonomous instruments, which sit on the ice or float in holes, far from the ship."

"The expedition's own noises, meanwhile, have forced atmospheric scientists to build special defenses. At a site called "Met City" a half-kilometer from the ship, a barrier nearly as tall as a person shelters an instrument that uses pulses of sound to measure the density of air, and thus gain insight into the structure of the atmosphere. The barrier is designed to deaden any artificial noise that might rumble across the seascape, such as blasts of the ship's horn and the whine of snowmobiles and nearby electronics"

"Then there is the Polarstern's sooty exhaust—a huge problem for the many MOSAiC scientists studying the Arctic's unusually clean air. The researchers want to better understand the sources and fates of aerosols—tiny particles suspended in the atmosphere—that contribute to the formation of small ice crystals within clouds. The number of crystals can determine whether a cloud acts as a blanket to warm Earth or an umbrella to shield it from solar radiation. But scientists aren't sure exactly where Arctic aerosols originate: Are they swept north from land, or are they formed by ocean organisms and sent skyward by breaking waves?"

"To gain some insight, Lauriane Quéléver, a chemist at the University of Helsinki and her colleagues will spend the next year pulling air samples through tubes mounted on a refashioned shipping container that serves as her lab. Instruments will parse the samples, analyzing and counting particles.

"Quéléver was astonished to find that the number of particles soared to 28,000 per cubic centimeter—a few thousand times greater than the typical Arctic level—when a second icebreaker arrived to swap instruments, personnel, and fuel. "I really hope that I'm going to get some very natural and pristine data," she says. "Otherwise I can just go home."

"A snowstorm or strong wind could help her and other scientists by clearing the air, but that rarely happened during my stay. When I visited CU atmospheric scientist Byron Blomquist, he was trying to collect air samples at a tower hanging off the ship's bow. But his instruments weren't sampling anything; they had automatically shut down after an alarm signaled that exhaust from the stern of the ship was enveloping the tower. Inside his container, pumps roared like vacuum cleaners as they pushed clean air out through his instruments, to prevent contamination by the smog."

"Less than 24 hours after the Polarstern settled in, the ship's emissions were smudging the ice. I noticed a black flake as large as my fingernail within the icy floe, removed a mitten and picked it up, rubbing the flake between my fingers. It turned to an oily smear. At the spot where the Polarstern had just spent the night. There hung a thick yellow and brown cloud. "Just think," one researcher said, "if we open the Arctic to shipping it's all going to look like that."
Title: Re: MOSAiC news
Post by: A-Team on November 20, 2019, 10:59:02 AM
That's disturbing: not really seeing ice thickening at PS location on Cryo2Smos
Here the time series are using 26 rolling weekly averages according to the Cryosat2 freeboard  / Smos thinness merger of observational ice thickness. There is some thickening over this period in the 0.8 to 1.2 m range. Oddly the ice is thicker to the southeast of the Polarstern's position.

It's hard to say whether that is notably fast or slow relative to past years because there's no long term consistent data set using these satellites and the refined merger algorithm.

Mosaic, in their floe planning, expected to find 1.2m ice here back on October 5th. That is 17 days before the first data frame here and 43 days before the final frame (which has finally attained that thickness). So it's probably fair to say that 1.2 m thickness is quite late.


Technical note: after setting the rectangle bounding the Polarstern's drift over these dates (using locations in the S1AB database from sailwx), set the color picker in Gimp to radius 5 which will fill the bounding box and take the average. Then fill a small overlaid rectangle with this color and pick the whole image with the non-contiguous color selector, capturing the local selection on the palette bar after adding 0.05 m subdivisions from the grid tool. The desired product (ice thickness growth in the Polarstern's vicinity) is then the animation of the palette bar. This could be done on the original png file without the -45º rotation to 'Greenland down' or better still by utilizing the nicely done netCDF file in Panoply which includes error estimates etc and has the option of exporting and analyzing numeric values of the equal area projection pixels. However this won't change bottom-line talking points obtained from much faster image analysis.
Title: Re: MOSAiC news
Post by: A-Team on November 20, 2019, 11:44:36 AM
Hefaistos calls our attention to another excellent BBC piece on the Akademic Fedorov trying to get home by Martha Henriques. It is best read in its entirety but a few highlights are being posted below:

How not to get stuck in the Arctic sea ice

News reaches us that boxes of kit and the Polarstern’s large gangway fell into a widening stretch of water.

Odd, no mention of this :( event at 'Follow_Mosaic' :). Possible allusion to it in Shupe's AGU blog. I struggled with 'boxes of kit'. Did the reporter mean boxes of clothes, unloaded scientific equipment or just stuff/things in general? Did they sink to the bottom of the sea or were they retrieved? Ditto the large gangway, loss of that leaves them stranded on or off ship, other than the mummy box chair unloaded by crane.

The Polarstern  is looking at a week of total blah weather ahead according to GFS. I don't expect any significant net drift; there's no indication of when or if the transpolar drift wind pattern will set up. Ice deformation can act from afar but I don't expect that this week because the millions of sq km of weak ice acts as a sponge that limits long range teleconnection of compression and extension.

However the Mosaic floe is looking very beat up after the storms and wind divergence on the two S1AB available for Nov 20th:

S1B   2019 11 20 T 06:02
S1B   2019 11 20 T 04:24

The AK rams the same piece of ice back and forth, maybe 70 times. The drift of the ice meanwhile carries the ship north. During those hours of ramming, the ship drifted so far   that it got back almost to its starting latitude to the north before we finally broke through.

Then the ship gets stuck a second time a few hours later and begins a second period of ramming. That’s when the captain decides to turn on the ship’s reserve engine. The Fedorov has four engines, but rarely uses all at once because this ramps up the ship’s fuel consumption. The fourth engine does the trick, helping the Fedorov break free again.
The captain really really did not want to get stuck for the winter in the ice. The ship is sitting unusually high in the water after the crew shifted scientific cargo onto the Polarstern plus 700 tons of diesel. The loss of weight left the Fedorov sitting so high in the water that the hull reinforcement area is now floating above the ice pack. The Fedorov is not a true icebreaker to begin with.

If the Fedorov were to get stuck, we would have two options: help from the Polarstern or hailing a nuclear-powered icebreaker such as the Yamal. "They are all busy and you don’t know when you will get one. And of course they are very, very expensive.”

The photo below shows how the 25 m wake sealed up almost immediately. The ship was in a compressive regime so ridging was almost immediate.
Title: Re: MOSAiC news
Post by: uniquorn on November 20, 2019, 11:47:32 AM
Here the time series are using 26 rolling weekly averages according to the Cryosat2 freeboard  / Smos thinness merger of observational ice thickness
Nice analysis
there's no long term consistent data set using these satellites and the refined merger algorithm.
The merged cryosat2-smos v2.02 data appears to go back to nov2010 at AWI (someone's been busy :) ) so a mid term comparison could perhaps be made.

It's been a long journey through google, guesswork, commas and brackets to buoy labels. Today I got the lucky click. So, an update on drift speed of the meereis Pbuoys ( closest to Polarstern from nov14-20, latest data at ~04:00, with labels. (temporarily without tails)

edit: Polarstern is currently roughly half way between p204 p201 and p207. The buoy on the edge of the floe 'fortress' STIPAKAF ;) is not shown here.
somewhat thicker ice previously also known as fortress

Added an overlay of Pbuoys with labels near Polarstern, circled in red, on today's S1B 04:24 image. The buoy colours just happen to be inverse of drift speed of a much shorter animation. It was an easy way to make them more visible. Click for full resolution.
Title: Re: MOSAiC news
Post by: Archimid on November 20, 2019, 02:04:48 PM
I suggest the term "fortress" is permanently banned to describe supposedly highly dependable thick ice. It may be jinxing things.

A-Team thanks for the amazing series of posts.

 A seasoned Arctic sailor/explorer saying the Polar stern is like a "5 star hotel"  is not likely the same judgement a much less field seasoned scientist might reach. I think that given the environment they face,  a warm ship is imperative. Good food has "magical powers" in stressful situations. Entertainment, good rest and privacy are all required for optimal operation of long missions,  under -20C temperatures, in absolute darkness, over a cracking surface, surrounded by hungry polar bears.

 The Polarstern and its crew of live subjects are not there just to do experiments in the Arctic, they are part of the experiment. They cannot remove themselves from it. They can only minimize their impact and keep their biases in check.  That is not easy because their presence there is like fire on ice.

 This is already amazing research, and this is only the beginning.
Title: Re: MOSAiC news
Post by: A-Team on November 20, 2019, 09:01:12 PM
Well put, Archi.

I say lay on the amenities, whatever it takes for creature comforts. They have been worried about sustaining Leg 2 morale since the get-go. They'll be beyond the reach of planes, helicopters and even support icebreakers over that time frame.

Mosaic has not released a ship's roster so we don't even know whom to thank. There's crew of 44 and capacity for 80 scientific and technical staff at any given time according to wiki. Most of the people are there to maintain complex instruments at remote sites (no easy job) though scientific team leaders are alongside working too. The breakthrough on internet bandwidth has made a big difference on who needs to be present.

Esther Horvath, photographer and communications manager of the MOSAiC expedition "wants to document the unknown faces on the front lines of climate science. "Who are the scientists? This is what I'm extremely interested in; to show climate change stories through the eyes of scientists, showing how they live in such an extreme remote location."

Chief scientist:
Markus Rex PS122/1: 20 Sep 2019 – 15 Dec 2019
Christian Haas PS122/2: 15 Dec 2019 – 15 Feb 2020
Torsten Kanzow PS122/3: 15 Feb 2020 – 15 Apr 2020
Markus Rex PS122/4: 15 Apr 2020 – 15 Jun 2020
Dieter Wolf-Gladrow PS122/5: 15 Jun 2020 – 15 Aug 2020
Markus Rex PS122/6: 15 Aug 2020 – 14 Oct 2020

The photo today shows some of the damage from recent ice dynamics. We've seen this already on Sentinel but don't know the specifics. However Mosaic has been very cagey about providing a revised map of Ice Camp as-built (and re-built and re-built again) or shareing measured ice elevations above and below.

For example, the open lead necessitating the bridge has itself been cropped out of the photo. We have no idea where the Ocean City and Remote Sensing Site are located today nor how serious the fracture is nor how to follow it on remote sensing.

I don't think this secrecy serves them. The damage control and data hoarding is pure paranoia. No ship radar with 100 Mbps internet? Dumbing down GPS position -- do they fear a cruise missile? What is someone going to do with bearing data beyond a scarcely publishable fourier analysis?

What it boils down to is somebody on the grant committee -- Mosaic dipped deeply into a pot shared with Antarctica and Greenland -- said 'this is never going to work plus it's been done before by N-ICE2015 and SHEBA'. And if they had access to minute by minute floe motion, would now be saying 'I told you so, no way time evolution of a single floe can be followed for a whole year'.

So it seems to be about embarrassment. They are making zero headway on the drift, have no prospects of drifting over the Pole, and the floe is rearranging itself daily if not disintegrating, undercutting the  key talking point about research novelty. This is why Shupe chose the name 'Fortress' for a crummy ice jumble and put it on Mosaic maps.

Today saw the usual turmoil on the Mosaic floe and also some puzzling (since winds have abated) regional torque with the ice no longer moving coherently over the short time frame between two S1AB. Divergent wind stress from yesterday cannot be the attribution because there's not even short term conservation of linear or angular ice momentum because of way too much frictional dissipation.

The two Sentinels are co-registered on the Polarstern (red dot); the faux interferometry that shows complex regional motion in this coordinate frame used the S1AB grayscale average for the 3rd luminance channel of the HSL 'RGB'.
Title: Re: MOSAiC news
Post by: uniquorn on November 20, 2019, 10:56:00 PM
Well, if nothing else, it's a pleasure to have almost daily multiple sentinel images of the same area and a wide range of buoys to determine, eventually, how to interpret those images. Sometimes the devil is in the detail.

At risk of overkill, while setting up for a longer term buoy overlay onto S1AB animation I came across this. nov17-18 with 50% intermediate frame, click to run
Title: Re: MOSAiC news
Post by: uniquorn on November 21, 2019, 11:12:34 AM
A lot of movement overnight looking at polarview ( New leads on both sides of PS.
Title: Re: MOSAiC news
Post by: A-Team on November 21, 2019, 04:27:57 PM
A lot of movement overnight
This was the worst ice dynamics yet ... and just after they got done laying a bridge over a recurrent lead with scrap palettes and a wooden sled. It is unfortunate that the remote experimental stations have to be tethered to the ship with power, data and fuel lines because these are subject to breakage and burial.

The massive rift chain to the Polarstern's southeast (fresh leads are black on S1AB) shows the response of the ice to to divergent wind stress: extensional faulting resembling NW trending Nevada basin and ranges as the Pacific Plate scrapes past the N American -- and about on the same distance scale. Both play out slowly in time; here the ice failed a couple days after the "84º" wind divergence event pictured in the GFS post above.

A parallel fault zone runs above, below and so far around the Mosaic floe. So far, it has mostly been around because the Fortress is not the path of least resistance for fractures (being thicker). The two Sentinels for the day are in and 'follow-mosaic' :) seems to run a couple days behind events, so unless skies are infrared-clear we won't know until 03:30 utc on Friday what is currently going on.

No question though that the Mosaic floe has experienced some strong ice dynamics even though the wind has been and will be mild short-term. The shifting ice we can see between Sentinel orbits only 3.25 hrs apart may or may not translate to significant damage to remote towers and lines.

The Polarstern itself, forming a barrier much higher than ice, seems to attract ridging, which on the stern side would seem to require daily resetting of slack lines mooring the ship to ice anchors. This recurrent lead/ridge may have originated from the icebreakers maneuvering early on.

Between onboard pollution from the ship's stacks and daily repairs to deployed sensors, scientists may not be getting the steady data streams expected. It would be no better on another floe. Trip leaders said early on that this was probably the last possible year for such an expedition. Maybe it was last year.

It's always been clear that Sentinel radar images, like Ascat scatterometery, arrives at sub-optimal visual contrast but it's never been clear how to best fix a given image, much less make a matching stack for a time series given variations between different orbital angles and nadirs.

Sentinel currently provides 82 images back to mooring on Oct 5th with only five days of missing coverage. The attached S1AB csv database has been merged with sailwx, AwiMet and nullschool GFS to bring in location, wind speed, wind direction, air temperature and links.

The easiest thing to do in terms of small file sizes, convenient format, quick turn-around and pioneering a pipeline for the the ultimate unattended objective fix of the jp2 is use the jpg for now and its intrusive graticule, followed by the Level tool in gimp, as shown in the mini-tutorial attached.

Sentinel images on ice are inherently speckled and while 'there's a app for that'  a slight unsharp mask can bring further small benefits. One size does not fit all however: improving a 100x100 km scene is not optimal for smaller sub-scenes like the Mosaic floe. There we would like to maximally improve the resolution or clarity of the image right around the Polarstern and the Mosaic floe.
Title: Re: MOSAiC news
Post by: A-Team on November 21, 2019, 07:16:32 PM
Awright! AWI finally posted an updated but already outdated map of the ice camp and its drifting pieces. The bad news is that the map is badly out of focus because designers did not anticipate what 'social media' would do resizing it for phones. This topic will never be trending with millennials; few could even locate Norway on a map.

I have not been able to locate the actual map. Actually it is very affordable to have an ordinary web site and simply post stuff in html 1.0 and upload intact big figures with ftp. In fact they could just use my site for free and get their incompetent graphics fixed to boot. They really shot themselves in the foot with this crazy complex javascript and cascading style sheet eye candy. It doesn't work.

Next we read about how they cannot track locations of their remote equipment. Apparently they don't co-install a buoy, tracker beacon, two-dollar flasher or radar reflector on expensive remote equipment (OPM: other peoples money). They could have just emailed uniq on their 100 Mbps internet to get the current drift.

The fuel cell failure mode is exactly what they would get in Minnesota on a cold day. The rising number of mundane equipment failures makes me wonder about pre-trip testing standards. This is an austere lunar landscape, not a mid-latitude campus.

Reading to end of this blog, it appears one co-leader has a very loose grip on what drives TransPolar Drift (in recent years, not much and very erratically) and on what is going down right now: one cyclone chasing another when TPD anti-cyclones are way overdue. They seem not to look at GFS even 2-3 days out for a drift forecast.

The way things are going -- and given what is coming -- perhaps it is time to consider a staged withdrawal:

-- Forget about fancy remote area deployments, pull back to the ship, put out more autonomous buoys, do helicopter forays to benefit satellite photo interpretation, carry out excursions to measure ice thickness, let the ship loose and motor slowly into the wind to keep the bow air clean. The ship moored to solid ice makes for a poor platform not fit for purpose because unavoidable emissions severely impact atmospheric and other monitoring goals.

-- Wind down Leg 1 in an orderly manner and consider downsizing, repurposing or even eliminating Leg 2. The Mosaic floe as originally envisioned is dead in the water. It is being torn apart and rearranged almost daily; no purpose is served by continued monitoring the core ice jumble-ridge which is atypical and unrepresentative of the Arctic ice pack.

-- Don't admit to planning mistakes but don't continue with them either. Give the redesign a new wrapper called responsive resilient adaptive management (RRAM) or similar.

11/9/19 Another Failed Mission
Postcards from a frozen icebreaker – Part 12 19 Nov 2019
By Matthew Shupe

L1 radiometer flight as high on the agenda today… but kept getting pushed back. Including by a bear visit, which closed down most operations. But finally in the afternoon we were able to hit the air. Loaded our gear on the helicopter….. sled, ladder, shovel, feather duster (great for instrument cleaning), tool box, numerous safety bags, rifle for the bear guard and a spare, personal kits (need those spare gloves), and most importantly our replacement power systems.

It is about 280 lbs…. two big batteries and a fuel cell, all set up in a box. We fired it up for about an hour before the flight to get it all toasty warm inside. Then shut it down, closed the box, and loaded it on the helicopter.

On site the plan is to quickly get it over to the flux station, plug it into a fuel cartridge, and fire it up again, to stay warm while we prepare the station for the power system transplant. Such a great plan…… but unfortunately the remote controlled helicopter landing lights at the remote station did not work, so we flew around for 1.5 hour looking for it.

So tough to find as everything is white (and snow covered) but it is totally dark out. Part of the challenge is that GPS coordinates quickly become outdated due to the ice drift. We get a reading from a buoy from ½ hour before but the whole pack has moved. This unsuccessful search had me really bummed and wondering if/when we would find this site.

It all went off without a hitch or at least without a big hitch on 11/10/19. Well planned in advance, we had the right tools and our specially concocted power system in a box. Beautiful clear skies and cold…. Below -30C for the first time at MOSAiC. The helicopter dropped us off at the L1 site, some 15 km away from Polarstern. Our new power system is getting colder. It won’t start if it gets below the freezing point.

We started up the spare system right away so it could keep itself warm, then opened up the old system, dark and cold, to remove the frozen system. The exhaust system was the culprit, a huge frozen beard extending down from where the water exhaust drips out. Ice extending up the exhaust tube
Title: Re: MOSAiC news
Post by: uniquorn on November 21, 2019, 08:43:40 PM
They could have just emailed uniq
One day I'll post a picture of our satellite dish strapped to a tree :) .

Made a mistake after playing with the buoy animation but left it as is since it shows the full path. It may be the sudden change in direction that opened up all the leads. A bit late, I was catching up with the spacex thread.
Title: Re: MOSAiC news
Post by: A-Team on November 21, 2019, 11:33:41 PM
that sudden change in direction opened up all the leads
Or whiplash. When the eye of a hurricane/cyclone passes overhead as it kinda did here, the wind reverses direction. Extensional leads rather than compressional ridges because ice on the edges moves centrifugally outwards. But where exactly and what good would advance knowledge do for the Polarstern?

In terms of replacing the white base under your buoy animations with appropriately dated S1AB or nullschool GFS winds (to get at the correlation pictorially), the S1AB go about 20 hours between 3 close coverages and the GFS 3 hours whereas the buoys commonly report hourly. So there is somewhat of a mismatch in time resolution to buoy GPS.

The Simb3 buoys report every four hours. However most buoys can be programmed to call in at whatever interval, from ten minutes on up. Some may be able to take downlink re-programming calls.

Windy gives update intervals and the time of update release (as of 2016 unfortunately) for all the common weather satellites and has stopped providing Arctic ECMWF.

On the four Simb3, call them abcd, retrieving their record of 924 dial-ups back to Oct 6th deployment revealed quite a mix of buoy position reporting combinations that complicate matters for making two delaunay triangles or just one  (or just an inter-buoy line) consistently.

The attached csv database is tricked out with extra sort columns to enable extraction of any desired sub-collection. The Simb3 are key to local ice thickness development, in combination with whole-ocean 25x25 km cryo2smos.

636 abcd   (all buoys reporting)
086 bcd    (buoy a not reporting)
041 cd     (buoys ab not reporting)
012 abd    (buoy c not reporting)
012 acd    (buoy b not reporting)
011 c      (buoys abd not reporting)
006 abc    (buoy d not reporting)
002 ac     (buoys bd not reporting)
002 bd     (buoys ac not reporting)

Uniq and macID have built a better mousetrap. That is, one-hour ice movement is much more refined than two-day OsiSaf as a better match to the intrinsic time scale of winter ice movement.

That is, the PS lat lon changed, in 1026 available hour increments at awiMet as poorly measured by one dp data are distributed as below. Note 0.1 in lon is a lot less distance travelled than 0.1 in lat this far north; the distribution estimate could be refined by using 4 hr windows. The Polerstern is currently moving very slowly south and east.

667 no change lat, no change lon
151 no change lat, westward 0.1 lon
117 no change lat, eastward 0.1 lon
010 0.1 south in lat, no change in lon
004  0.1 north in lat, no change in lon
002 no change lat, 0.3 westward in lon
006 no change lat, 0.2 westward in lon
008 no change lat, 0.2 eastward in lon 
002 0.1 north in lat, 0.1 west in lon
003 0.1 north in lat, 0.1 east in lon
010 miscellaneous

While ice motion so described is limited to inside the buoy envelope, it could give advance notice to the Polarstern of leads and ridges outside their immediate location in advance of the next S1AB. The buoy pattern is in effect an imaging device, resembling the discretized ommatidia of a small invertebrate eye.

OsiSaf uses pattern recognition but those point features (virtual buoys) change from day to day and can be quite sparse. OsiSaf is not currently pointed at S1AB but could be, giving ultra-refined ice motion between timestamps in conjunction with the buoy product.

Clearly uniq could dump the gridded underlying data into netCDF time series format to distribute the underlying numerology though trailing tails (but not colors) would be lost.
Title: Re: MOSAiC news
Post by: A-Team on November 22, 2019, 11:47:17 AM
The situation has gotten increasingly dire in the immediate vicinity of the Mosaic ice camp as extensional forces have opened multiple km-wide bands. A second Sentinel image of 05:46 has just come in that provides a snapshot of ongoing motion -- the situation has worsened considerably in the last three hours. PolarView has just now posted a third intermediate time, the 04:08, but we won't be able to follow events further until tomorrow morning other than hourly weather and drift which are unremarkable (there's no storm) since the last S1AB:

   Lat  Long  YY-MM-DD  UTC     Wind       T(C)  hPa
  85.7  120.7 19-11-22 10:00    5   50    -16.3 1016.0
  85.7  120.8 19-11-22 09:00    4   40    -17.0 1015.5
  85.7  120.8 19-11-22 08:00    5   10    -16.1  1015.0
  85.7  120.8 19-11-22 07:00    4  340    -16.1  1014.5

This event will be extremely disruptive to all deployed experimental equipment and effectively destroys the floe for purposes of studying its evolution over a year. Let's hope the Polarstern and all the people aboard stay safe as the event continues to unfold today.

This is a very unfortunate situation ultimately attributable to climate change, its amplification in the Arctic Ocean and the long-term trend to thinner, more mobile ice that cannot resist wind stresses.

The upper two images follow Mosaic convention with north up, the first needs a click to display full size; the lower animation has S1AB orientation of the Pole down the 120º meridian with inverted insets in coordinates attached to the ship at 2x enlargement.  The 4x enlargement is also north down after contrast leveling and light unsharp mask.

Some of the 87 surviving autonomous buoys out of the 100 deployed in the Mosaic project will likely succumb to the same ice pack deformations affecting the Polarstern. So far, they all reported on the 22nd or 23rd with the exceptions below. All but the last two are Chinese buoys that have previously had reporting delays.

300234068118580   SVP    PRIC   MOSAiC   15 11 19   86.19   118.51   
300234010077180   GPS    TUT    MOSAiC   19 11 19   86.08   117.27   
300234065091830   GPS    TUT    MOSAiC   19 11 19   86.01   123.00   
300234065090840   GPS    TUT    MOSAiC   21 11 19   85.51   120.54   
300234065980590   GPS    TUT    MOSAiC   21 11 19   85.73   123.98   
300234065981590   GPS    TUT    MOSAiC   21 11 19   85.61   118.57   
300234065984580   GPS    TUT    MOSAiC   21 11 19   85.95   121.98   
300234065985570   GPS    TUT    MOSAiC   21 11 19   85.92   121.06   
300234067705700   IT      AWI    MOSAiC   21 11 19   85.75   121.63   
.................90094   ITP   WHOI   MOSAiC   21 11 19   85.68   121.98   
Title: Re: MOSAiC news
Post by: uniquorn on November 22, 2019, 04:35:35 PM
Why so many big leads during relatively calm weather? I reread the two posts above :)

Update on drift speed, this time looking more closely at the polarstern area from nov19-22 ~03:30. PS is roughly half way between p201 and p207. The diagonal is 120E, the line top right is 85.5N. I'll attempt to add more graticule with labels and a rough time as we go along.
I wonder if they can feel any of that movement, in particular the recent jolt to the north shown by the more easterly buoys.

Clearly uniq could dump the gridded underlying data into netCDF time series format to distribute the underlying numerology though trailing tails (but not colors) would be lost.
@macid, have you ever tried ncdf4 (
Title: Re: MOSAiC news
Post by: blumenkraft on November 22, 2019, 04:38:59 PM
Wow, thanks for pointing that out, Uniquorn.

But what's the chicken and what the egg here? ;)
Title: Re: MOSAiC news
Post by: A-Team on November 22, 2019, 05:07:44 PM
Why so many big leads during relatively calm weather?
Even though wind speeds have been mild, wind velocity has been very confused in the 200x200 km sector centered to the SE and including the Polarstern. The weak ice of today experiences mechanical failure upon being pulled in different directions even under moderate stress.

The alternative, a delayed reaction to stresses from storm last weekend, doesn't hold water: too many days have elapsed. However that storm was likely a major contributing factor in establishing the initial ice fractures that later became big leads, opening easily under mild divergent winds.

The next cyclone rolling in will brush the Polarstern on Nov 24th before wandering off to Severnaya Zemlya. Winds will be fairly strong (peaking ~32 km/hr) for a day but GFS does not foresee surface winds anywhere near the 51 km/hr of the last storm. Wind stress goes roughly as the cube, so the previous event was 4.3x worse.

Note Uniq's buoy trajectories are in effect a non-gridded replacement for OsiSaf ice motion with a fantastically improved time resolution, an hour vs 48 hours. Given that buoys report location to 4-5 decimal points, whereas OsiSaf is applying AI to low resolution all-Arctic imagery, the accuracy is much higher with the buoy mesh.

The tangent vectors to these curves at the times the S1AB are taken (not marked or paused yet) are then the arrows that should be drawn over the high resolution imagery instead of what we see at mosaic_multisensor. These arrows will be very accurate both in magnitude and direction.

Even if F not quite = ma under the circumstances, it is close enough for citizenry work. Here we want to get at the force acting on the floe in which the buoy is emplaced or rather its rigid body extension. Here you would want go back to an old indian trick called Newtonian Differences rather than differentiate fitted continuous curves.

Set up a column of positions, let the adjacent column subtract t from t-1 and fill down, let the third column do the same for the second, recalling change of position with time is velocity and change in velocity with time is acceleration which with mass fixed amounts to force acting (geometrically the tangent to the velocity curve). These new columns are to be colored differently in supplemental animations though the time steps and positions remain the same.

OsiSaf ice motion is severely biased by the big moves during the 48 hour block; if for example, these might be in the first two hours with the latter 46 providing little displacement, then the image served will not be at all current. This explains the apparent incomparability with GFS 3-hr winds.
Title: Re: MOSAiC news
Post by: gerontocrat on November 22, 2019, 05:34:46 PM
Just when I was going to post a little gif A-team makes it redundant.

Here it is any way -
- calm tomorrow,
- 24 Nov       South wind 30 kmh
- 25-26 Nov  East wind 20 kmh
- 27 Nov much calmer but still FJL next stop.

Given the state of the floe and the surrounding area it all looks a bit dodgy, but just as well those big winds in the Beaufort / Chukchi / Bering Strait are a long way away.

As they say in every episode of all the best Police series "Take care out there".

gif plays 3 times & stops
Title: Re: MOSAiC news
Post by: A-Team on November 22, 2019, 06:57:26 PM
Let's get this right because this is a very serious ongoing event.

Supposing this weekend storm had a causative role in the present troubles at the Polarstern, it might be worth overlaying the 3-hr nullschools over the changing S1AB, using the PS positions in the computed nullschool url as provided for everyone's convenience in an earlier cvs attachment.

The synthetic problem though is the resolution of nullschool maxes out at its '3000' scale whereas the S1AB ROI for Mosaic is just a postage stamp then under the GFS, with vice versa no better. However S1AB still conveys the lead situation zoomed out so there might be a workable compromise that doesn't overshoot the 700 pixel forum width too badly.

Technical note: as above, take whole window screenshots and layer up in Gimp. To avoid jerking the nullschool image with inadvertant mouse-overs, use keyboard commands lik j and k to advance and back the time by 3 hours. Three days is 24 layers; that won't result in an overly large final file. Duplicate the file twice and crop to the url and data box for wind speed. Crop the main file to final size and enlarge the canvas on the duplicates to match. Then tile up as three layers, add the S1AB layers duplicate to match, add transparency to the GFS, flatten over the radar, then slice the tile over in ImageJ, save as animated gif, open and re-save in gimp with good pauses where appropriate. YES YOU CAN.

85   S1B   2019 11 22 T 05:46   22 11 19   05:46   85.7   120.8    4   320   -14.8
84   S1B   2019 11 22 T 04:08   22 11 19   04:08   85.7   120.8    4   320   -15.0
83   S1B   2019 11 22 T 02:30   22 11 19   02:30   85.7   120.8    4   350   -14.9
82   S1B   2019 11 21 T 06:43   21 11 19   06:43   85.7   121.0    4   360   -16.2
81   S1B   2019 11 21 T 03:27   21 11 19   03:27   85.7   121.0    6   30   -16.0
80   S1B   2019 11 20 T 06:02   20 11 19   06:02   85.8   120.5    6   230   -13.8
79   S1B   2019 11 20 T 04:24   20 11 19   04:24   85.8   120.5    8   240   -15.3
78   S1B   2019 11 19 T 07:00   19 11 19   07:00   85.8   120.6    6   240   -11.2
77   S1B   2019 11 19 T 05:21   19 11 19   05:21   85.8   120.5    7   240   -15.4
76   S1B   2019 11 19 T 03:43   19 11 19   03:43   85.8   120.5    8   240   -15.3
75   S1B   2019 11 18 T 06:19   18 11 19   06:19   85.9   120.8   14   20   -10.6
74   S1A   2019 11 18 T 05:30   18 11 19   05:30   85.9   120.9   16   10   -10.2
73   S1B   2019 11 18 T 04:41   18 11 19   04:41   85.9   121.0   16   10   -10.5
72   S1B   2019 11 17 T 05:38   17 11 19   05:38   86.0   122.5   13   320   -15.7
71   S1A   2019 11 17 T 04:49   17 11 19   04:49   86.1   122.5    4   320   -16.2
70   S1B   2019 11 17 T 04:00   17 11 19   04:00   86.1   122.4   14   310   -17.7
69   S1B   2019 11 15 T 05:54   15 11 19   05:54   86.2   118.4   11   170   -26.1
68   S1B   2019 11 15 T 04:16   15 11 19   04:16   86.2   118.3    2   260   -15
67   S1A   2019 11 15 T 03:27   15 11 19   03:27   86.2   118.3    2   260   -14.9
66   S1B   2019 11 14 T 03:35   14 11 19   03:35   86.2   118.2    9   190   -14.5
65   S1A   2019 11 13 T 03:43   13 11 19   03:43   86.1   117.9    9   200   -13.8

AWI communications have been strangely unscientific. The daily 'follow' blog is misdated, a day or more behind events depicted; photos have no timestamps, exifs are stripped; ship time is updated weekly but not provided, we have no idea what UTC the news refers to; the twitter feed is hardly used, no one on board is sharing despite huge bandwidth, the Helmholtz blog has gone dead, ship GPS is obfuscated and so on. It is not a good idea to apply spin templates from political campaigns to scientific matters. Honesty is the best policy.
Title: Re: MOSAiC news
Post by: macid on November 22, 2019, 09:27:22 PM

Clearly uniq could dump the gridded underlying data into netCDF time series format to distribute the underlying numerology though trailing tails (but not colors) would be lost.
@macid, have you ever tried ncdf4 (
can read netcdf and still some room left for learning, what should go in the netcdf, just a conversion of the bouy csv with dimensions for lat, lon, time and values for the working buoy data?

I don't understand what you want to do with it A-Team tbh but happy to look into
Title: Re: MOSAiC news
Post by: uniquorn on November 22, 2019, 10:21:14 PM
He could load it into panoply and look at stuff without R skills.

Here is a buoy overlay onto yesterdays 03:27 S1B. The buoy locations are taken from frame 3 of a 23 frame animation of yesterday's buoy data (I haven't worked out how to limit hours yet). macid may correct me but I think R animate makes frames from an average of available data, letting you choose how many frames make up the animation. Buoys that send data every 10m would probably be averaged. Perhaps it would be interesting to select only those buoys and run a more detailed ani, depending on their locations. Many of the pbuoy's data ends at 2300 when I download it s we have to wait. 3 or 4 hours is a lot of movement these days.
The file is big but it's click to run  It's only Neven's storage bill slowly creeping up ;) Optimising reduced file size by 40%. An animation of this poses some challenges.

Polarstern shows up clearly between p201 and p207.
should have reversed the order
Title: Re: MOSAiC news
Post by: A-Team on November 22, 2019, 10:38:08 PM
why netcdf?
It is first about mainstreaming the buoy project. It's such a good one that resistance is futile.

For better or worse, nc and hdf have become the meeting ground for sharing climate data, excel/mysql wrapped in steroids. System integrators -- builders of the immense robotic pipelines of climate science -- do not want to crawl a hundred sites, massage a hundred formats, write a hundred unresponsive sysadmins, nor tweak other people's ad hoc code.

In fact the whole idea is not to look at the raw data at all but assume it is schema-compliant so a remote climate modeler or weather prediction provider can ingest it over and over without further intervention.

It is second about getting out of banks of numbers into bottom-line pictures: working on a more limited scale within Panoply, an open and active low learning curve netCDF data viewer, data type combiner and map-maker that allows the average joe/sephine to put out a decent and original product, for example changing projection to equal area or re-scaling to overlay properly on satellite products, or here correlating ice mobility with say surface wind speed or vertical ice temperature profile.

In other words, it is better to crunch pictures than numbers. Or rather multiple correlated stacks of pictures. Why? Because you can see what you are doing, because there are ten thousand intuitive photoshop-type algos, because the data is inherently indexed by location and timestamp.

It's all about rapid prototyping. Work with the pictures until you know there will be a result, then go back to the numbers and do it right.

Is this a spec for implementing buoy position and sensor data as netCDF? I would say no, it's little more than a vague vision statement looking down the road to better sharing.

Is the priority so high that the weekend should be spent immersed in human-unreadable binary? For me, I would say no to that.
Title: Re: MOSAiC news
Post by: uniquorn on November 23, 2019, 01:15:11 AM
Wide area view from Sentinel1AB with merged intermediate frames at 50%, nov17-22. No buoys yet.
click to run
scale=30% to reduce size
Title: Re: MOSAiC news
Post by: uniquorn on November 23, 2019, 01:32:24 AM
closer view at full res. Looks like there was a bit of whiplash.
Title: Re: MOSAiC news
Post by: A-Team on November 23, 2019, 10:30:06 AM
Here is a stomach-churning zoom centered at the Polarstern to go with that very effective hangover blur above. The last S1B of Nov 22nd has been rotated so that the pole is to the bottom left.

The second image shows a cyclone forming in the upper Fram and wandering up to the Polarstern's location before drifting off to the Kara Sea. The effects on leads and ridging would be fairly minor except for pre-conditioned fissures. Whatever the drift induced in the ship, even if it mimics transpolar drift, has nothing to do with transpolar drift.

The mp4, adapted from Uniq above with the Mosaic floe circled, shows the very unfortunate situation the Polarstern is in relative to large scale failures in the ice pack. Be sure to set on loop so it will rocks back and forth.

The 3x enlargement shows extreme disruption of the Mosaic ice camp over this time frame. Black lines are open water of new leads; white lines are pressure ridges. The Polarview portal to Sentinel imagery is currently badly broken and no files of any kind are available yet for today, the 23rd.

Mp4 are now easy to make in forum-acceptable form by saving ImageJ stacks to avi and then applying cloudconvert. It requires dimensions be even.
Title: Re: MOSAiC news
Post by: uniquorn on November 23, 2019, 01:16:16 PM
update on close buoys, nov19-23. The diagonal to the legend is 120E with 2deg intervals, the line top right is 85.5N, with 0.1deg intervals. No labels. Testing semi transparent buoy markers.
Westerly buoys get two northerly lurches, the easterlies only one.
Title: Re: MOSAiC news
Post by: A-Team on November 23, 2019, 05:20:01 PM
Right. At first it looks like one of those pen machines putting a personal touch on a massive junk mail campaign. But the trails actually differ quite a bit in their details upon trying to overlay them by a simple translational move. The question is, how to distinguish deformation from shear and discontinuities such as a lead opening.

The long PolarView weekend continues. I wrote them, they are off somewhere not responding. The pink square masking goes away if all but S1 are de-checked; problem is now in the feed. No new images have been ingested since the 22nd.

Mosaic is going to new extremes to keep the world uninformed.
Title: Re: MOSAiC news
Post by: blumenkraft on November 23, 2019, 07:55:23 PM
Slightly related, since we had the 'how does the ship influence the environment around the ship' talk.

Satellite tracking shows how ships affect clouds and climate

Link >>
Title: Re: MOSAiC news
Post by: blumenkraft on November 24, 2019, 01:41:54 PM
60 frames, 51-minute increments via SNPP, Day&Night band.

Click to play
Title: Re: MOSAiC news
Post by: uniquorn on November 24, 2019, 02:55:08 PM
helicopter trip?
Title: Re: MOSAiC news
Post by: blumenkraft on November 24, 2019, 03:05:04 PM
I thought so too. :)
Title: Re: MOSAiC news
Post by: uniquorn on November 24, 2019, 04:26:42 PM
Do you have a link or much larger single image?
Title: Re: MOSAiC news
Post by: blumenkraft on November 24, 2019, 04:40:09 PM
I zoomed the shit out of it for you. ;)

Title: Re: MOSAiC news
Post by: uniquorn on November 24, 2019, 05:22:20 PM
Thanks. Quite a big lead in that rough location. Maybe they had to move some gear. The overlay is on to nov22 S1B as there were no images yesterday, so the 120 lines don't match up. click to run
Title: Re: MOSAiC news
Post by: A-Team on November 24, 2019, 06:20:38 PM
The image below takes Uniq's animation #303 above, attaches the hour to each of the 100 frames, then adds the S1AB of that hour when one of the nine relevant ones is available. The png below just looks at frame 77 which had the latest S1.

Relative to buoy tracks, this time was well after the hairpin 180º but close to the final wiggles which were double to the east but triple to the west, at a bad time for the deployed Polarstern equipment.

The ESA/Copernicus could not have picked a worse time to skip two days of coverage of the Mosaic project. We know satellite went overhead at the usual times; we don't know why they shut down the radar that makes EW-format scenes. Maybe it was set to some other mode for some other purpose (?). At any rate, the RAMMB becomes the supplemental tool of choice.

... aims at fulfilling, during the routine exploitation phase, the observation requirements of the Copernicus services and of ESA/EU member states ... a secondary objective is to satisfy other SAR user communities, ensuring continuity of ERS/Envisat, considering requirements from the scientific community, as well as from international partners and cooperation activities.

The elaboration of a pre-defined observation plan necessitates solving, a priori, the potential conflict among users (e.g. different SAR operation modes or polarisation schemes required over same geographical area).Wave Mode (WV) continuously operated over open oceans, with lower priority versus the high rate modes. Interferometric Wide swath (IW) and Extra Wide swath (EW) modes operated over pre-defined geographical areas: over seas and polar areas, and ocean relevant areas, pre-defined mode is either IW or EW. In exceptional cases only, emergency observation requests may alter the pre-defined observation scenario, potentially requiring the use of the Stripmap (SM) mode.

Steps and rationales in placing an S1 image under its buoy time frame:

rotate S1 of 05:46 22.11.19 cw 45º in ImageJ
measure scale between 85-86 at 2712.46 pixels or 813.7 pixels per 0.3 deg of lat
animation scale between 85.6 and 85.9 which is 0.3 deg of lat is 369.6 pixels
consequently the S1 needs to be downscaled by 45.42% to fit under animation frame 77 need to find 85.6 120 on the S1 to know how far to drag it.
given 85.0 and 86.0 corners, it will be 0.6 * 2712.46  = 739.2 pixels down from 85.0
add a blank layer and put a green dot there.
put a big red * over the Polarstern on the image
add frame 77 and final frame 100 overlays and co-slide to 85.6 120
autocrop to get rid of S1 that is not under frame 77.
note PS is 53 pxl left and 6 pxl down relative to buoy P204 on frame 77
for future PS put a magenta star 53 pxl left and 6 pxl down relative to buoy P204 on frame 100
sailwx is saying PS is at 85.7 120.3 on frame 100 which is at 04:30 on 11.23.19
put a orange star 27.4 pxls up from 85,7 (in a blank layer, don’t cover up data).
copy out P204’s route, color it cyan and translocate it from PS f77 to PS f100 for
that gives hypothetical intermediate drift that we can test with RAMMB
ship GPS is only 1 dp so has a large uncertainty orange box
save a new-from-visible png enlarged to ~700
repeat for all the frames that have a nearby S1 time and post to forum later
most of the steps are the same for all S1 and
steps vary simply if Uniq changes buoy animation scale and orientation

05:46   22 11 19
04:08   22 11 19
02:30   22 11 19
06:43   21 11 19
03:27   21 11 19
06:02   20 11 19
04:24   20 11 19
07:00   19 11 19
05:21   19 11 19

The buoy timer is attached; the S1AB csv is a few posts back
Title: Re: MOSAiC news
Post by: A-Team on November 24, 2019, 07:05:36 PM
Quite a big lead in that rough location. Maybe they had to move some gear. The overlay is on to nov22 S1B as there were no images yesterday, so the 120 lines don't match up.
If the Rammb is enlarged 3x but its PS held at the PS S1 location, then the 120's do fall into line which shifts the second location to the magenta half-circle.

Mosaic has not disclosed the location of remotely deployed equipment, only sites within a km of the Polarstern. We are not certain this is a helicopter but it is surely not the icebreaker bringing supplies as that is not due for several weeks.
Title: Re: MOSAiC news
Post by: uniquorn on November 24, 2019, 07:29:32 PM
<If the Rammb is enlarged 3x but its PS held at the PS S1 location>
Maybe that should be from the projected PS loc for nov23

A major breakthrough for the buoy animations today. We now have dates! Though please see below for a view on how accurate they may be. This one goes back to nov17 to show todays movement retracing the previous path. We also have minimal manually added lat/lon labels.

Tech note: Best efforts are made to make the frame count the same as the number of hours, so the time should be accurate to the hour, probably much closer.
transition_along makes the following variables available for string literal interpretation, in addition to the general ones provided by animate():
    frame_along gives the position on the along-dimension that the current frame corresponds to
I would never have guessed 'frame along' in a million years, but, eventually, after asking the right question....

Some background on the method used for the buoy animations
When we animate data visualisations we often do it by calculating intermediary data points resulting in a smooth transition between the states represented by the raw data. In gganimate this is done by adding a transition which defines how data should be expanded across the animation frames. Underneath it all most transitions calculate intermediary data representations using tweenr and transformr — so far, so good.

What we have glanced over, and what is at the center of the problem, is what state of the data we decide to use as basis for our expansion. If you are not familiar with ggplot2 and the grammar of graphics this might be a strange phrasing — data is data — but if you are, you’ll know that data can undergo several statistical transformations before it is encoded into a visual property and put on paper (or screen).
Title: Re: MOSAiC news
Post by: blumenkraft on November 24, 2019, 07:43:52 PM
We are not certain this is a helicopter but it is surely not the icebreaker bringing supplies as that is not due for several weeks.

Agreed. You only see it in one frame. If it was a ship you should see it way longer.
Title: Re: MOSAiC news
Post by: A-Team on November 24, 2019, 07:59:48 PM
Maybe that should be from the projected PS loc for nov23
Good idea, will implement along with enlarging the underlying S1 and optimizing the contrast for enlargement. Or maybe leave the Rammb as is and shrink the S1 as that is easier to back up to full or even enlarged once the suspect region is identified.

85.7  120.35 19-11-23 06:30    5  220  for location of PS at time of double heat source and wind
85.7  120.8   19-11-22 05:00    for location of the earlier S1B so a decent move

The frames are a whole orbit apart? That is usually a bit over an hour for near-polar, sun synchronous. Says 51 minutes above, so low orbit. Another possibility is heat from a fuel cell starting up. Or burning up -- drain holes were blocking up with refreezing melt water from their process. They were replacing them the other day by the Polarstern. And a remote one in the AGU blog. Of course those would be brought in by a helicopter so go figure.

Given the situation with Sentinels, it's probably worth looking into optimizing the Rammb archive a bit more. The contrast as initially provided uses about a fifth of the histogram. And some of the frames may provide recognizable details in the ice depending on local cloud cover. Bottom line though is the resolution is way worse than Sentinels.

Airplane engine heat maybe possible; is this a flight route between Asian and London?. Polar-5 and Polar-6 are not going out there until the piston bullies can groom an airstrip; the ice ridging  and dynamics make that problematic.
Title: Re: MOSAiC news
Post by: blumenkraft on November 24, 2019, 08:14:47 PM
IDK if this makes sense, but could it be an aeroplane also?
Title: Re: MOSAiC news
Post by: macid on November 24, 2019, 08:56:11 PM
A major breakthrough for the buoy animations today. We now have dates! Though please see below for a view on how accurate they may be. This one goes back to nov17 to show todays movement retracing the previous path. We also have minimal manually added lat/lon labels.

Tech note: Best efforts are made to make the frame count the same as the number of hours, so the time should be accurate to the hour, probably much closer.
transition_along makes the following variables available for string literal interpretation, in addition to the general ones provided by animate():
    frame_along gives the position on the along-dimension that the current frame corresponds to
I would never have guessed 'frame along' in a million years, but, eventually, after asking the right question....

amazing work on the labels, graticules and dates now, you should put your own name on it ;) I couldn't get frame_along to work with something else, to much headaches in the end. It's easy to make it work one way.. but combine stuff and suddenly you have to play hostage negotiator.

in Panoply I can't see a way to load non-gridded data, and a sensible way to arrange this buoy data into grid format eludes me, use a fine grid and fill non-positions with nulls? Calculated vector values may make sense to put in a grid but I need a few courses to get there.
Title: Re: MOSAiC news
Post by: A-Team on November 24, 2019, 09:54:43 PM
put buoy data into netCDF for broader data integration?
Thanks for looking into it. Sure, nulls and fine grid. The thing to look at is OsiSaf .nc to see what they did for sea ice motion vectors, just copy what they did with the buoy data. We're looking for Geo2D file format in Panoply, geo-referenced. Anything less just produces distorted rectangular grids. Panoply will overlay buoy tracks on cryo2smos thickness. Some weirdness from the buoy data covering so little of a whole ocean polar stereographic.

Panoply netCDF, HDF and GRIB Data Viewer ... - NASA GISS › tools › panoply › download
Sep 30, 2019 - Panoply netCDF, HDF and GRIB Data Viewer. Download Panoply. Panoply requires a computer with Java 8 (or later version) installed

amazing work on the labels, graticules and dates now
I'll second that! Compare it to the very best that this $150,000,000 project seems capable of producing. 0.01% of that budget could have got them first-rate graphics. All those unsecured boxes of kit that sank off the side, how much of the budget went down with them? Flying around 1.5 hr in the helicopter looking in vain for an expensive installation because they didn't track on GPS?

Talking to the spouse (who has ZERO interest in anything scientific) about all the Mosaic breakdowns. Response: the expedition was always just a lark, adventuring.


Going somewhere?

 86.0 120.7 19-11-25 08:00 11 130 -20.8 1003.1
 86.0 120.8 19-11-25 06:00 12 140 -18.5 1001.7
 86.0 120.9 19-11-25 03:00 12 140 -18.6 1000.1
 86.0 121.0 19-11-25 02:00 12 140 -18.8 999.7
 86.0 121.1 19-11-24 22:00 12 150 -19.7 998.0
 86.0 121.2 19-11-24 21:00 12 150 -19.3 997.7
 85.9 121.3 19-11-24 14:00 11 160 -16.7 996.0
 85.9 121.4 19-11-24 07:00 15 170 -17.2 995.6
 85.8 121.3 19-11-24 04:00 15 180 -16.0 996.2
 85.8 121.2 19-11-24 02:00 15 190 -15.4 997.2
 85.8 121.1 19-11-23 23:00 15 190 -15.6 999.9
 85.8 121.0 19-11-23 22:00 15 180 -15.8 1000.8
 86.0 121.2 19-11-24 21:00 12 150 -19.3 997.7
 85.9 121.2 19-11-24 20:00 12 150 -19.2 997.5
 85.9 121.3 19-11-24 16:00 12 160 -17.8 996.3
 85.9 121.4 19-11-24 07:00 15 170 -17.2 995.6
 85.9 121.3 19-11-24 06:00 15 170 -16.6 995.7
 85.8 121.2 19-11-24 02:00 15 190 -15.4 997.2
 85.8 121.1 19-11-23 23:00 15 190 -15.6 999.9
 85.8 121.0 19-11-23 22:00 15 180 -15.8 1000.8
 85.8 120.9 19-11-23 20:00 13 190 -15.9 1002.8
 85.8 120.8 19-11-23 18:00 11 190 -17.5 1004.7
 85.8 120.7 19-11-23 16:00 11 200 -19.3 1007.1
 85.8 120.6 19-11-23 15:00 11 190 -19.9 1007.9
 85.7 120.5 19-11-23 12:00 10 190 -21.0 1010.7
 85.7 120.4 19-11-23 10:00 8 200 -20.9 1013.3
 85.7 120.3 19-11-23 06:00 5 220 -19.1 1016.1
 85.7 120.3 19-11-23 05:00 4 220 -18.8 1016.6
 85.7 120.4 19-11-22 22:00 4 30 -17.5 1019.1
 85.7 120.4 19-11-22 17:00 8 60 -22.4 1018.2
 85.7 120.5 19-11-22 16:00 8 50 -21.2 1017.9
 85.7 120.6 19-11-22 13:00 7 50 -14.9 1016.9
 85.7 120.7 19-11-22 10:00 5 50 -16.3 1016.0
 85.7 120.8 19-11-22 09:00 4 40 -17.0 1015.5
 85.7 120.9 19-11-21 22:00 4 340 -15.0 1011.5
 85.7 121.0 19-11-21 06:00 4 360 -16.2 1003.8
 85.7 121.1 19-11-21 01:00 5 20 -17.4 1002.2
 85.7 121.2 19-11-20 23:00 6 10 -18.1 1001.9
 85.8 121.3 19-11-20 21:00 7 20 -18.5 1001.7
Title: Re: MOSAiC news
Post by: uniquorn on November 25, 2019, 02:16:50 AM
3 closest buoy comparison. Animations created separately, note the time differences. Well within an hour, but need watching. ctr
Title: Re: MOSAiC news
Post by: Tor Bejnar on November 25, 2019, 06:43:29 AM
Somebody could write some (classical styled?) music to which those buoys could dance to.
Title: Re: MOSAiC news
Post by: A-Team on November 25, 2019, 11:26:21 AM
One Sentinel has come in so far this morning, the 02:54 of Nov 25th. It just barely captured the Mosaic floe. The previous S1, the 05:46 of Nov 22, means a 3-day gap in coverage unprecedented back into September. Polarview is now ingesting mid-morning images so no more coverage of the Polarstern for today.

All the open leads have sealed so we will never know what happened during the chaos in the early morning of the 22nd other than what is in the three images available. However the weaknesses created by divergent wind stress will stay weak for the remainder of the winter and may re-open later. The red line in the final frame below may be a persistent lead or ridge associated with swaths early on made by the two icebreakers. 

The version below of Uniq's most excellent three-buoy comparison is squeezed to increase the separation of the tracks and runs back and forth as an mp4. Be sure to set controls to loop. The file size is so small on these because all the blank spaces compresses dramatically; the forum could show 50x the time period within its 10 MB limit.

On the 3rd animation, I've collected 16 of the 344 frames of Uniq's 3-buoy animation that have Sentinel scenes at the same time. There's enough empty space to add an actual thumbnail from the S1AB inventory of Mosaic floe images.

The bottom image shows the track of the Polarstern as adapted from the Rammb infrared sequence above.

Technical note: It is easy to add a dimmed out rest-of-track to each of the earlier frames to make it clear what is coming next. That is done by desaturating the final frame, excising the date and scale, duplicating 16x, tiling, lowering opacity and setting to 'darken only' in gimp, then reslicing the 'make new layer from visible' to the final animation.
Title: Re: MOSAiC news
Post by: uniquorn on November 25, 2019, 06:06:02 PM
Nice, the mosaic floe images give a bit more meaning to the movement info.
Today's update, still retracing. It should be noted that the buoy animations are rotated -45deg from Greenland down. Similar to the mercator default image.

The secret to rotation may be in here somewhere
proj.og = "+proj=longlat +datum=WGS84",
proj.out = "+proj=stere +lat_0=90 +lat_ts=0 +lon_0=0 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0",
or maybe not ;)
Title: Re: MOSAiC news
Post by: blumenkraft on November 25, 2019, 07:50:09 PM
60 frames, 51-minute increments.

Yes, baby, that's the right direction. :)
Title: Re: MOSAiC news
Post by: rog on November 26, 2019, 01:07:09 PM
Buoy movement with music.
Title: Re: MOSAiC news
Post by: A-Team on November 26, 2019, 01:41:23 PM
Very nice addition, rog!

Smooth sailing ahead? The rifting episode of 22 Nov 2019 is over but the last four Sentinel-1 images (blue lines) are still show quite a bit of turmoil in the main experimental area. The Polarstern has been very slowly moving north but mostly moving west the last two days under moderate wind speed (5th column), winds direction swinging around (6th column) under cold temperatures and unremarkable barometric pressure.

Here the tenth of a degree of latitudinal shift from 86.0 to 86.1 represents a distance of 11.1 km whereas that distance requires a degree and a half of longitudinal change (at 86.0). So over the time frame of the table below the Polarstern has moved 17.7 km. They are currently 1472 km away from their destination of Longyearben, Svalbard which would be ~180 days away if this pace kept up (it won't).

 86.1  119.0 19-11-26 14:00 7 70 -27.0 1011.1
 86.1  119.0 19-11-26 13:00 9 70 -26.3 1011.1
 86.1  119.1 19-11-26 12:00 7 70 -26.5 1011.2
 86.1  119.2 19-11-26 11:00 7 70 -27.1 1011.9
 86.1  119.2 19-11-26 10:00 7 60 -27.8 1012.1
 86.1 119.3 19-11-26 09:00 8 70 -26.9 1012.3
 86.1 119.4 19-11-26 08:00 7 70 -26.3 1012.2
 86.1 119.5 19-11-26 06:00 8 70 -25.4 1011.8
 86.1 119.5 19-11-26 05:00 8 80 -24.1 1011.8
 86.1 119.6 19-11-26 04:00 7 80 -23.5 1011.6
 86.1 119.7 19-11-26 03:00 8 90 -22.7 1011.6
 86.1 119.7 19-11-26 02:00 8 80 -22.0 1011.6
 86.1 119.8 19-11-26 01:00 8 90 -21.7 1011.6
 86.1 119.9 19-11-26 00:00 8 90 -23.1 1011.5
 86.1 119.9 19-11-25 23:00 9 100 -23.8 1011.3
 86.1 120.0 19-11-25 22:00 8 100 -24.1 1011.2
 86.1 120.0 19-11-25 21:00 9 110 -24.2 1010.7
 86.1 120.1 19-11-25 20:00 8 110 -24.8 1010.4
 86.1 120.2 19-11-25 19:00 9 120 -23.7 1009.9
 86.1 120.2 19-11-25 18:00 9 120 -24.1 1009.4
 86.1 120.3 19-11-25 17:00 9 120 -23.7 1008.9
 86.1 120.3 19-11-25 16:00 9 120 -23.4 1008.2
 86.1 120.4 19-11-25 15:00 10 130 -23.5 1007.3
 86.1 120.4 19-11-25 14:00 10 130 -23.6 1006.7
 86.1 120.5 19-11-25 13:00 10 130 -23.6 1006.0
 86.1 120.5 19-11-25 12:00 10 130 -23.5 1005.5
 86.0 120.6 19-11-25 11:00 10 130 -23.2 1005.0
 86.0 120.6 19-11-25 10:00 11 130 -22.4 1004.4
 86.0 120.7 19-11-25 09:00 11 130 -22.2 1004.0
 86.0 120.7 19-11-25 08:00 11 130 -20.8 1003.1
 86.0 120.8 19-11-25 06:00 12 140 -18.5 1001.7
 86.0 120.9 19-11-25 05:00 12 140 -18.4 1001.0
 86.0 120.9 19-11-25 04:00 11 140 -18.2 1000.7
 86.0 120.9 19-11-25 03:00 12 140 -18.6 1000.1
 86.0 121.0 19-11-25 02:00 12 140 -18.8 999.7
 86.0 121.0 19-11-25 01:00 11 140 -19.1 999.2
 86.0 121.0 19-11-25 00:00 10 140 -19.8 998.7
Title: Re: MOSAiC news
Post by: psymmo7 on November 26, 2019, 03:58:23 PM
...Buoy movement with music.

Thank you Rog. ---much appreciated
Title: Re: MOSAiC news
Post by: blumenkraft on November 26, 2019, 04:21:58 PM
Buoy movement with music.

Well done, Rog! Love it.

Now, when can we expect the dubstep version? ;)
Title: Re: MOSAiC news
Post by: macid on November 26, 2019, 04:44:57 PM
Nice, the mosaic floe images give a bit more meaning to the movement info.
Today's update, still retracing. It should be noted that the buoy animations are rotated -45deg from Greenland down. Similar to the mercator default image.

The secret to rotation may be in here somewhere
proj.og = "+proj=longlat +datum=WGS84",
proj.out = "+proj=stere +lat_0=90 +lat_ts=0 +lon_0=0 +k=1 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0",
or maybe not ;)
Coordinate conversion uses Proj4js (, no rotation option for stereographic projections. Manipulating the longitude in the dataset prior to conversion would achieve something similar (as long as there's no terrain height in the plotted area) or a there use rotate functions for x,y datasets after conversion.

But next is rotating the map and graticules, Plotsvalbard map would be messed up.. may as well go to raw ggplotting at this point. Which I should do anyway, because I can't get PSvalbard to work in Ubuntu (trying to take developing a bit more seriously)

Now, when can we expect the dubstep version? ;)
drop at 11-23 please

Title: Re: MOSAiC news
Post by: blumenkraft on November 26, 2019, 05:00:56 PM
drop at 11-23 please

Exactly! :D
Title: Re: MOSAiC news
Post by: uniquorn on November 26, 2019, 05:09:24 PM
that drop has potential for development :)
Manipulating the longitude in the dataset prior to conversion
Went with lon = (data$longitude..deg. +45), lat = data$latitude..deg.    from the line before which appears to have the desired effect, though doesn't affect the underlying map, as you say. Should be ok till they hit land (and no bathy)

So, we have rotation and lat/lon labels. You wait ages for a lucky click and then 3 come along at once. And then music.

That manually placed 86N label is at 86.1 Will fix it and repost later(see below)

Tech note: Lat/Lon data is to 3 or 4 decimal places, rounded here for visual reasons. There are still some overlaps.
Forgot to change lon lines so 120E is not shown. Check the numbers

Title: Re: MOSAiC news
Post by: A-Team on November 26, 2019, 05:29:54 PM
There is a golden opportunity to study how ice drift correlates with wind direction during an unusual period of steady wind speed and direction in in late October. As Nansen observed during the voyage of the Fram, motion of the ice was almost always offset from the direction of the wind. However he lacked the big picture that we have today (eg basin-wide cyclone).

The response of the Polarstern is shown in the two-frame animation and the csv of its variables below. Note both the zonal and meridional drift components were linear, with moderate drift to the north but a strong component to the east, forming a large angle to the wind direction (which is counter-intuitive but expected).

The ship presents a very large target to the wind but is of a negligible mass compared to the larger ice pack. Mosaic has declined to make public the ship's bearing (ie alignment with wind) over time, presumably to reserve for themselves (in 2023) the capability of using the GFS forecast to make a few days of ice motion forecast.

Attached also are the wind roses for wind direction and wind speed during the 229 hours of this low variability event.
Title: Re: MOSAiC news
Post by: uniquorn on November 26, 2019, 08:24:47 PM
<how ice drift correlates with wind direction>
For future reference, what was the offset angle during that period? It looks a bit less than 45deg.

Looking under the ice, whoi itp102 is part of the mosaic buoy array, though not currently featured in any animations yet, but it can be expected to experience similar drift. The detail on the drift track is just about good enough to make out the path we are all familiar with, also reminding us of the overall scale of movement. Note the small change in temperature and senility as the buoy possibly passes over roughly the same area. An enthusiast may want to look into that ;)
The microcat is mounted at only 6m below the surface.
ITP102 was deployed on a 0.7 m thick ice floe in the Transpolar Drift on October 10, 2019 at 85° 7.9 N, 135° 34.1 E in collaboration with the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from the Russian Research Vessel Federov. On the same icefloe, a Naval Postgraduate School Arctic Ocean Flux Buoy (AOFB) and Seasonal ice mass balance buoy were also installed. The ITP includes a second generation prototype MAVS current sensor operating on a pattern profiling schedule including 2 one-way profiles between 7 and 760 m depth each day and SBE-37 microcat fixed at 6 m depth.
Title: Re: MOSAiC news
Post by: uniquorn on November 26, 2019, 08:55:11 PM
The polarstern position may possible be estimated to a higher degre of accuracy than 1dp by calculating the mid point of p201 and p207. The correction to the animation above(deleted) includes those calculated coords, shown in red. I haven't been able to animate them along with the buoys yet.
Note how the drift track crosses over a similar area 3 times. Perhaps itp102 data correlates with that crossover point.
Tech note: Lat/Lon data is to 3 or 4 decimal places, rounded here for visual reasons. There are still some overlaps.
interest level=1/10?
edit: cropped to less than 580px for better display
Title: Re: MOSAiC news
Post by: Tor Bejnar on November 26, 2019, 09:07:04 PM
Thanks Rog!  Music makes it easier to actually watch the path of ice movement (and multiple times, to boot!).

Decades ago a classically trained friend did lots of improv playing, sometimes like (for example) being influenced by the way leaves blew around outside during blustery weather.  I imagine a computer program today basing 'music' (okay, sound) on buoy movement direction, speed, changing buoy relations (opening leads/growing ridges) [pitch, note duration, scale direction, volume, other variables, other aspects of sound], put to harmonic (or at times dis-harmonic) scales/chords.
Title: Re: MOSAiC news
Post by: A-Team on November 26, 2019, 09:15:46 PM
Snow at the Remote Sensing Site at 86.13, 118.58 on Nov 26th, is still barely over the birkenstocks and looking very susceptible to wind re-distribution. Thermal insulation? Not really but maybe keeps the wind from sweeping heat off the ice surface.

Meanwhile, back at the AGU blog collection, co-leader Matthew Shupe writes about earlier equipment disruptions (but not about the big one on the 22nd):


But then in the following day, just after we performed the major power system transplant on our L1 site, our L2 site failed. I examined all of the available information, and it told me a story: The inclination of the system changed abruptly by an angle that was ~3 times larger than the change from when Dave and I climbed on a station together; at about this same time the sonic anemometer instrument quit. The rest of the system’s communications went out about 8 minutes later, just after a couple spikes in one of the shortwave radiation sensors.

I speculated that this was a bear because the force exerted on the system must have been about 3 times that of Dave and I, and the fact that things were operating fine before and parts failed over the course of multiple minutes instead of all at once. With our brief visit by helicopter today, it appears that this speculation is true. It looks like the bear walked around the station and first yanked on a cable to the sonic anemometer, shattering a metal connector. He then jerked on a few other cables, totally pulling them apart and breaking another connector that was inside our main box. He pulled on our met mount, up at 2m height so he must have been standing on hind legs; this bent it down to one side.

And then he found the good stuff: the exhaust from the fuel cell power system is water. (As an aside, I wonder how bears drink water at all? I guess they must melt snow). It looked like he was sucking on the exhaust, pulled it out and chewed on a heat cable, mangling the copper outlet tube. This last part may be the hardest to fix as we have spares of all the instruments and cables, but will need to figure out a solution. All-in-all, it appears that, after another major field surgery, we should be able to resuscitate this system and get it operational again.


It started small, as they all do. About 1m across at the point where the spine road leads past Ocean City out towards Met City. The crack meandered and there were places to easily just step across. No major changes over the day. We went on with our daily work at Met City.

In the afternoon a couple of us went out to do some power line maintenance. As it was there was little slack in our power network to accommodate cracks, so we disconnected some of the power line straps and pulled available slack to the area around the crack. Loops of heavy power cable sitting near the edge.

I estimated that it could absorb a widening to perhaps 20m. It held out well beyond that, but in the end it still wasn’t enough. Saturday evening the crack opened to >20m in places, then made a lateral shift of as much as 100m.

Met City, Remote Sensing site, and the ROV Oasis all moving more forward towards the centerline of the Polarstern from the starboard side. A bit reminiscent of the bid lead we had 22 years ago at SHEBA; that one moved our camp 500m to the side and made it necessary to power the camp on generators for the rest of the project.

But here, at MOSAiC, with this big shift, somehow Met City survives. It appears to be crack free, all instruments standing, and amazingly the power is still on! By Sunday morning there was a shear in the other direction, back beyond the original connection point, opening, closing.

And finally coming to a rest at nearly the original starting point. Met City power was finally interrupted at about 7am local time, its characteristic green light going out. Sunday was a planned day off so no science activities on the ice but the logistics team was still busy; they work very hard in support of this mission.

By the end of Sunday, Met City is still standing but dark, and the 30m mast has an odd tilt to it. Will have to explore that tomorrow."
Title: Re: MOSAiC news
Post by: blumenkraft on November 27, 2019, 02:56:16 PM
Wait, what?

Could that be Starlink satellites?
Title: Re: MOSAiC news
Post by: Archimid on November 27, 2019, 03:16:46 PM
Title: Re: MOSAiC news
Post by: blumenkraft on November 27, 2019, 04:59:24 PM
New Arctic Drift podcast!

Link >>
Title: Re: MOSAiC news
Post by: A-Team on November 27, 2019, 05:27:20 PM
The first product below montages five fragmentary scenes from AWI mosaic_multisensor that suffice to show the entire drift to date; the composite is then set over the S1B from today.

The motion can be described as two stalls connected by a rapid linear drift. The Polarstern is continuing to drift 0.4º west at constant latitude in the nine hours following the hour of the S1B scene. However it has not exited its box into new lat/lon territory. Winds remain moderate at 9 m/s.

GFS sees retrograde motion for next 5 days: more tangling of the trail, no poleward motion, west yes but south with that. Overall drift will be not Fram-ward but rather towards western Siberia but not dramatically so. And that's been the case for the subsequent 15 hours (though lat is not provided to sufficient accuracy to follow southerly drift).

The actual latitude as measured on 41m resolution Sentinel is 86.16621 which rounds to 86.2 but is notably less, namely 6 km to the south. The longitude is 117.09º which rounds to 117.1º so the AWIwx is wrong, probably from just cutting off digits instead of rounding to nearest tenth.

  86.2  117.0  19-11-28  06:00  6  30  -28.5  1011.9
  86.2  117.0  19-11-28  05:00  6  40  -30.2  1012.3
  86.2  117.1  19-11-28  04:00  7  50  -30.9  1012.8  S1A 04:08
  86.2  117.2  19-11-28  03:00  7  50  -31.1  1013.0
  86.2  117.2  19-11-28  02:00  8  60  -31.1  1013.1
  86.2  117.3  19-11-28  01:00  7  50  -31.2  1013.3
  86.2  117.3  19-11-28  00:00  7  60  -30.8  1013.4
  86.2  117.4  19-11-27  23:00  7  60  -31.2  1013.5
  86.2  117.4  19-11-27  22:00  8  70  -31.1  1013.7
  86.2  117.5  19-11-27  21:00  7  70  -31.1  1013.7
  86.2  117.5  19-11-27  20:00  7  60  -31.1  1013.7
  86.2  117.6  19-11-27  18:00  7  70  -31.0  1014.0
  86.2  117.7  19-11-27  17:00  7  70  -30.5  1014.1
  86.2  117.7  19-11-27  16:00  7  80  -30.2  1014.1
  86.2  117.8  19-11-27  15:00   

The close-up continues to show rapid evolution of the Mosaic floe. It appears a lengthy lead has opened in front of the bow and partly frozen over. Challenges continue in keeping off-ship equipment collecting data.
Title: Re: MOSAiC news
Post by: A-Team on November 28, 2019, 12:09:34 PM
The diagram and spreadsheet below show a second method for accurately measuring latitude and longitude of the white dot on S1AB that represents the location of the Polarstern at the timestamp of the satellite image.

In the case of ship position near 86,120, the canvas is extended 4x 2713.6 pixels (1º of latitude) so that the North Pole is now in the image after rotating -15º to bring the 120º meridian into the vertical. The distance and angle are then measured from PS to NP which then provide, after some spreadsheet trivia, the desired location results. The circle of latitude of the ship can be drawn as well as supplemental meridians.

If the stack of 91 S1AB images from floe mooring to the present are aligned to 86,120 using the difference mode in Gimp, then all the high resolution lat,lon can be read off in one operation from a common fixed center at the pole which largely eliminates relative error. While the measure tool is fast and easy, it is limited to 2 dp in angle measure accuracy.

Thus a better alternative is simply to record the x,y position of the Polarstern relative to x,y  of 86,120 along with a virtual north pole. Then the lat,lon can be calculated to arbitrary precision from basic trigonometry without further photogrammetric measurements on the images and error assessed by probing the effect of bumping x,y by a pixel each.

The main source of error is ambiguity of position of the point 86,120 within the broad red geolocation swath provided by PolarView. The GeoTiff scene variant provided would have precise geo-referencing but the file size of these is enormous: 128 MB compressed which would likely scale to a terabyte for the growing S1AB archive.

Better still would be hourly (or ten minute) GPS readings from the ship itself, rather than 8 hr S1. All that has to be done there is for Mosaic to stop obfuscating its release.

Update:  another image has just been posted, S1B 2019 11 28 T 0635
Title: Re: MOSAiC news
Post by: uniquorn on November 28, 2019, 12:49:59 PM
a second method for accurately measuring latitude and longitude
Does that mean you've already done it so we don't have to? ;) I need one accurate starting point on, say, oct4 for a drift comparison test.

Looking at the close up S1AB's I think mosiac have really missed an opportunity to engage an audience in real time. It looks like quite exciting ice movements happen close to Polarstern. The sort of thing that interests webcam watchers worldwide (waterholes, peregrine falcons etc). There's plenty of light around the ship, where's the webcam???

Today's drift in slowmo so you can read the lat/lon and I dont have to label anything.
Title: Re: MOSAiC news
Post by: A-Team on November 28, 2019, 06:19:12 PM
Mosaic news is a big yawn. Ineffective. People want excitement.
Right, Mosaic is putting people to sleep with boring staff photos. A web cam of ridges crashing against the ship and scary leads opening and closing by the gangway, time lapse with an inset of the captain's instrument panel (GPS, pitch, yaw, bearing). Even an iPhone 6 can stream time lapse video with sound, I have one set up at the bird feeder. A live cam would not make a dent in the ship's excellent bandwidth.

Does that mean you've already done it so we don't have to?
Yes it does (because it turns out to be rather easy).

PolarView does this very accurately in an unpromising display option called 'jpeg2000 file (lossy)' that does not download the selected scene to disk as the icon suggests but rather opens a new tab running a plug-in (no installation required) called NSJSView 1.0. It is reminiscent of Nasa Worldview but better done.
While the ground resolution of S1AB is ultimately limiting, the remaining measurement uncertainty now is where to put the dot on the fuzzy Polarstern reflector. Here the ship beam axis and bow2stern crosshairs define a consistent center and provide an estimate of error associated with mouse position being off a pixel or two.

Nothing more is involved than finding the PS dot in each of the 91 S1AB and capturing it with a screenshot that includes the lat lon to four decimals. There seems not to be text capture in the contextual menu nor url change with mouse position (unlike nullschool) so those numbers have to be entered manually in the S1AB spreadsheet. (OCR will have problems with the '/' separator.) Gross typos can be caught by comparing round-off to one decimal data already in the db.

Rows will look like this (86.1642 116.9532 is the location of the 06:35 image):

S1A   2019 11 28 T 04:08 86.2   117.1   7   50   -30.9 86.1665 117.0933

So now we know where to put the dot and how big to make it on the Polarstern viewed as a big buoy (not seeing). 

The 91 S1AB do not quite jib with the 1392 hourly buoy GPS data points. Here the question is not how to interpolate -- R is statistical software offering every conceivable interpolation method and goodness of fit evaluation -- but whether to use the mosaic_multisensor track provided a couple of posts back, as AWI may have used secret high precision PS location data in drawing the red line.

In any event, it will be interesting to see how animated close-in P-type buoy triangulations relate to these high accuracy S1AB location points. Outer buoys will be affected to a greater extent because of additional remote transitory leads and ridging. The attached csv provides the high precision lat lon collected to date.
Title: Re: MOSAiC news
Post by: uniquorn on November 28, 2019, 10:56:37 PM
A live cam would not make a dent in the ship's excellent bandwidth.
Maybe they're paying by the MB ;) Those ( cams were interesting though, and quite popular here. Who is going to be interested in 2023?

Thought about posting more buoy data but after a classic facebook breakfast shot on I'm going with this from bbc.

Title: Re: MOSAiC news
Post by: uniquorn on November 29, 2019, 01:26:58 PM
drift update, 3 Pbuoys closest to PS - see below
Title: Re: MOSAiC news
Post by: blumenkraft on November 29, 2019, 04:12:56 PM
RAMMB-SLIDER's not updating -.-
Title: Re: MOSAiC news
Post by: A-Team on November 29, 2019, 09:12:38 PM
Rammb down, line of dots?
IT will be back in Monday after a long weekend.

'Follow Mosaic' was better today but long is the transect, on what floe is it located, what is its history and initial thickness, what have they found so far -- none of your business apparently.

Hippocrates once said, you cannot walk the same Arctic sea ice transect twice ... was this floe representative, what commotion has the site undergone in the last 60 days?

The location and date (but not the time, the exif was stripped) are given as 86.08 113.73 on the 29th. That would be well south of anywhere the Polarstern has been recently. However if the Polarstern persists in using "ship time" and changing that every Saturday (they say to better party with the incoming icebreaker at its meal times), the date itself becomes problematic.

The last few days have seen a brisk sub-gale force wind (2nd column, m/s) from a consistent direction pushing the ship steadily east with a touch of south. The ship is at a record easterly position at 113.8 but at an unexceptional latitude. Again, this is a great opportunity to study ice pack movement at a constant stress vector.

Assuming the work party photo was taken at the same time as the last of the four Sentinel-1AB this morning, the work site can be located approximately using the fabulous new PolarView plug-in from The exact study floe cannot be determined because of the lack of timestamp on the photo.

86.1   113.8   29   17:00   09   40
86.1   113.9   29   16:00   10   40
86.1   114.0   29   15:00   11   40
86.1   114.0   29   14:00   11   40
86.1   114.1   29   13:00   12   50
86.1   114.2   29   12:00   11   50
86.1   114.3   29   11:00   12   60
86.1   114.4   29   10:00   12   50
86.1   114.5   29   09:00   13   60
86.1   114.6   29   08:00   13   50
86.1   114.8   29   06:00   12   40  05:38   86.0079   114.8607
86.1   114.9   29   05:00   14   40  04:49   86.1120   114.9497
86.1   115.0   29   04:00   13   50  04:00   86.1220   115.0394
86.1   115.1   29   03:00   12   50
86.1   115.3   29   02:00   13   50  02:22   86.1262   115.2108
86.1   115.4   29   01:00   10   40
86.1   115.5   29   00:00   11   50
86.1   115.6   28   23:00   12   50
86.1   115.7   28   22:00   12   50
86.1   115.8   28   21:00   13   50
86.1   115.9   28   20:00   12   40
86.1   116.0   28   19:00   13   50
86.1   116.1   28   18:00   12   50
86.1   116.2   28   17:00   11   40
86.2   116.3   28   16:00   10   40
86.2   116.4   28   15:00   11   40
86.2   116.5   28   14:00   9   50
86.2   116.5   28   13:00   9   40
86.2   116.6   28   12:00   8   30
86.2   116.7   28   11:00   8   30
86.2   116.8   28   10:00   9   30
86.2   116.8   28   09:00   9   30
86.2   116.9   28   08:00   8   20
86.2   117.0   28   06:00   6   30  0635   86.1642   116.9532
86.2   117.0   28   05:00   6   40
86.2   117.1   28   04:00   7   50  0408   86.1665   117.0933
86.2   117.2   28   03:00   7   50
86.2   117.2   28   02:00   8   60
86.2   117.3   28   01:00   7   50
86.2   117.3   28   00:00   7   60
86.2   117.4   27   23:00   7   60
86.2   117.4   27   22:00   8   70
86.2   117.5   27   21:00   7   70
86.2   117.5   27   20:00   7   60
86.2   117.6   27   18:00   7   70
86.2   117.7   27   17:00   7   70
Title: Re: MOSAiC news
Post by: SteveMDFP on November 29, 2019, 10:26:31 PM

Hippocrates once said, you cannot walk the same Arctic sea ice transect twice ... 

I think you're paraphrasing Heraclitus, actually.  Rivers, though, of course.
Title: Re: MOSAiC news
Post by: uniquorn on November 30, 2019, 02:46:59 PM
drift update, 3 Pbuoys closest to PS, ~8days in 50frames
updataed below
Title: Re: MOSAiC news
Post by: uniquorn on December 01, 2019, 04:07:01 PM
drift update, 3 Pbuoys closest to PS, ~9days in 100frames.
This ani includes an estimate of PS location based on 10/17 distance between p201 and p207. Some coordinates taken from polarview images have been added in red to verify the rough path. The timing of the path passing close to the polarview points still needs to be verified.
Tech  note: PS points in red taken from a list collated by A-Team using the method here (,2906.msg238886.html#msg238886)
Title: Re: MOSAiC news
Post by: A-Team on December 02, 2019, 04:46:56 PM
coordinates taken from polarview images in red and collated
Coordinates  were shared earlier from the 106 Sentinel-1AB images available since the Polarstern moored on Oct 4th. These were hand-digitized using the fast and accurate new PolarView plugin.

No new S1AB images have appeared during the last 48 hours, very unusual. It means during all 16 orbital passes over the Polarstern, the sensors were either shut down, malfunctioning, taking scenes in interferometric mode, or taking images but suspending distribution. This happens every time the Mosaic floe is encountering disintegration issues. Coincidence?

The P-buoys give the ship's position 2-3 times a day, always in the early morning UTC hours. The accuracy is about a third of the ship's length. The timestamps refer to nadir or satellite passage over the center of the scene. While these are more accurate than we need (to the second), the minutes can be anywhere between hours.

Like most buoys, the three close-in P-buoys call in their GPS coordinates 24 times a day, every half hour on the half hour. Since 4 dp accuracy is important to measure ice pack deformation, the issue arises of how to best collate them with the erratic timestamps of Polarstern S1AB images.

The Polarstern's lat lon is seldom co-temporal with the buoys, only 15 times out of 106. However the other 91 can be linearly interpolated back to the nearest half hour using the rate of change of lat lon. The ones below are already synched to the buoys and do not need interpolation:

S1B   2019 11 29 T 0400   86.1220   115.0394
S1B   2019 11 22 T 0230   85.7352   120.8192
S1B   2019 11 19 T 0700   85.8011   120.5766
S1A   2019 11 18 T 0530   85.8556   120.8340
S1B   2019 11 17 T 0400   86.0595   122.4405
S1B   2019 11 10 T 0230   85.8219   115.9915
S1B   2019 11 07 T 0700   85.9198   116.7922
S1A   2019 11 06 T 0530   85.9191   117.7247
S1B   2019 11 05 T 0400   85.9509   118.8770
S1B   2019 10 26 T 0700   85.4533   127.4991
S1B   2019 10 19 T 0530   84.9215   133.1910
S1B   2019 10 14 T 0700   84.7783   134.5386
S1A   2019 10 13 T 0530   84.8574   135.0090
S1B   2019 10 07 T 0530   85.0846   134.3174

The Pbuoy dataset has various repairable glitches (shown below) not repaired by the buoy owner; the month-old errors are simply passed on 'as is' to the Meereis and sailwx portals to be ingested into Uniq's animation algorithm.

Since 94 - 12 - 3 = 79 other Mosaic buoys are currently reporting -- and some of these will have glitches of their own -- there is a need to repair the damage and regularize the data.

The best way to go is set up a master clock, say on the half hour back to the beginning, then hang all the data off it to synchronize analysis. Although Mosaic experiments often produce complex data types that don't fit in (below), they still be indexed in if that serves some purpose.

For example, a source like GFS nullschool only reports at 3 hr intervals so has gaps at 5 out of 6 positions, whereas sailwx and awiMet shipboard weather report hourly. Ascat reports 3 times a day but swath timestamps are hard to come by for the concurrent PS location. OsiSaf reports a rolling window of ice movement every two days between 12:00Z. Most satellite products (such as Amsr2 ice concentration or cryo2smos ice thickness) report every 24 hours.

On these forums, we are looking for scalability, transparency, regularization and portability:

Scalability: Any number of buoys or images can be tied to the master clock's indexing field; indeed all put into a single common file. The issue is keeping file size manageable over the course of the Mosaic year. If not, the latency on common operations like 'sort' or 'fill down' becomes unworkable. The key here is keep image collections such GFS weather pictures elsewhere, still indexed though by the master clock.

Transparency: This means suppling the data in human-readable data or image format such as plain txt, comma separated variables, netCDF, kml, gif, png, jpg or mp4 visible in the post itself or as an attachment anyone with an old cheap computer can download, open in free software and process for themselves. More and more climate change sources are using arcane binary formats the average person cannot work with.

Regularization: Errors, gaps and glitches should be repaired just once, rather than 50 people making the same tedious repairs 50 times over. To a certain extent, this is enforced by keying to the master clock. I will post repaired P-buoys, synched S1AB and reconciled sailwx/awiMet in a bit.

Correction and collation of databases can be done very rapidly if you still have a 25 year old Mac running MS Works 1.0; it has gotten much harder since.

Portability: The data should be immediately importable into other open software for specialized projects, such as Excel, Gimp, ImageJ or R for statistical analysis, charting, slide shows, animations and movies.
Title: Re: MOSAiC news
Post by: A-Team on December 02, 2019, 05:15:02 PM
Co-leader M Shupe has an excellent new on-site blog out; note that despite the Nov 27th tag the storm event being discussed only covers the 18-23 Nov 2019. More has happened since then

We could see the damage just looking at S1AB time series but it is great to have confirmation and  specific details beyond satellite resolutioon. Note buoys are not on the Mosaic floe and may be affected differently or not at all.

I don't think things would have gone better had they selected another floe; the ice was garbage everywhere at their latitude on Oct 5th and still is. Had they gone closer to the pole, transpolar drift would have become even more problematic than it is now: the GFS wind forecast translates heuristically to more south and east backtracking of their trajectory.

85.9  113.8 19-12-02 09:00    8  250    -27.1
85.9  113.4 19-12-01 21:00    8  300    -24.1
86.0  113.1 19-12-01 09:00   10  310    -21.8
86.0  112.8 19-11-30 21:00    8  340    -27.0
86.1  112.9 19-11-30 09:00    9   20    -28.0
86.1  113.5 19-11-29 21:00   10   30    -25.8

Postcards from a frozen icebreaker – Part 14
By Matthew Shupe 11/18/19

I was startled by the phone call shortly after midnight. Trouble at Met City. Felix had just arrived on the bridge for his night watch from 12-4am. He always takes a look around camp when arriving for his duties. And there was no 30m mast. Simply gone.

We had seen the crack before, and apparently it got active and pulled on some of the guy lines, ultimately pulling the mast down. The sonic anemometer failed right away, possibly from just being unplugged. Upon later inspection it is bent, can likely be straightened, re-calibrated, and put back into operation.

Our met sensor remained operational the whole time, including [while lying on the ground] after the fall. We will test both of these instruments against others, but it is looking like they will both live to see another field measurement.

The mast itself might also be salvageable. Some bent legs the ship can likely fix and a few damaged sections that will just be taken out of service. Thus, it may become a 25m mast but that would be better than nothing. Now we just need the ice to settle down so we can think about a redeployment.

The chaos has contributed to this feeling. Major ice dynamics running from the northwest to the southeast of us, across the bow of the ship. They have sheared our camp, and the Fortress, in half. This was part of a regional event with lots of ice motion, likely driven by a strong storm with very high winds.

Initially the lead opened many meters across, followed by some shear with the far side of camp moving towards the ship, then away again. In the last days it all moved again perhaps 500m.

Met City is almost directly in front of Polarstern while Ocean City remains approximately where it was (after a slight move to stay away from the ridge). A much longer daily voyage for us to get to Met City, and now it means bringing fuel cans to run generators. Met City is now very dark.

“Continuity” is a very important concept for MOSAiC. But it’s also a huge challenge in the current Arctic conditions. In the last week we’ve had so much ice movement, right out in front of the ship. We watched Met City move back and forth across the view from the bridge.

Intermittently we are able to reach it, going from floe to floe. While at other times there is no access possible. And this limited access impacts the continuity of our measurement on the ice. We are running Met City on a couple of generators but the runtime is such that we must refuel twice per day.

Last night the ice movement left us no route to Met City so the generator fan went out at 4:30 am local time. This limited access is leaving its mark on the Met City data stream but others experiments are also impacted.

Sampling sites have move further away or broken up entirely; the Ocean City hut had to be moved; the whole Remote Sensing installation will need to be relocated, and more. Continuity of the observations has definitely been compromised.
An outdated map of the Ice Camp layout was included, not attached below because it is one we have seen before, now presented at a blurrier resolution. It does not show the layout of the cracks and ridges discussed in the post.

Once again there is nothing but 404's in trying to locate the original full resolution file. Neither the new lidar elevation map nor ice bottom ROV imagery have been released in any form.

Last time I wrote the help desk, they got back to me saying the ship could only be contacted intermittently, even though we know today it had a 100 mbps internet connection ever since leaving Tromsø.
Title: Re: MOSAiC news
Post by: gerontocrat on December 02, 2019, 07:06:21 PM
The MOSAIC expedition was designed, funded and implemented on a simple single basic assumption, namely that there would be a nice big thick solid floe that would remain intact throughout the entire freezing season as it drifted around the Arctic.

Re-reading the early posts, it is difficult not to conclude that the floe chosen was the best of a very bad lot as there was no time left to look further.

Barneo 2019 was abandoned.

Mike Horn and Borge Ousland have had and are having an awful time on their little North Pole skiing expedition
Horn lamented the changing sea ice: “[It] is not only shrinking in size, but it has also become younger and thinner in recent years. This causes the ice to break up and move a lot faster than it used to, which are two of the biggest challenges we have encountered so far.”

So perhaps the MOSAIC expedition's basic assumption no longer holds? i.e n years too late?

Perhaps the methodology, i.e. continuous measurements on and of a single floe, no longer reflects the polar winter ice reality?

Perhaps the new reality is continuous change as ice moves, breaks up, reforms into different patterns?
Mike Horn's expedition...,2886.msg239192.html#msg239192
Title: Re: MOSAiC news
Post by: uniquorn on December 02, 2019, 09:21:27 PM
drift update, 3 close Pbuoys and PS estimated location, ~10days in 50frames
Title: Re: MOSAiC news
Post by: uniquorn on December 02, 2019, 09:51:39 PM
Perhaps the new reality is continuous change as ice moves, breaks up, reforms into different patterns?
Indeed. Late refreeze and rapid extent gain maybe has it's own problems. More obvious stretch marks perhaps.  nov27-dec2, ctr
Title: Re: MOSAiC news
Post by: A-Team on December 02, 2019, 11:33:23 PM
Mike Horn and Borge Ousland have had and are having an awful time... Perhaps the whole concept of continuous measurements on  a single floe, no longer reflects the polar winter ice reality?
The two adventurers are looking at very unfavorable ice movement for the next four days that will take them north and west faster than they can walk. The same thing happened to Nansen's foot party. The image below plots their nrt position at 08:29 utc 02 Dec 19 over nullschool GFS.

The idea of rescuers reaching them by sailboat or bringing food on skis seems very naive looking at the massively fractured ice leads ( The two are within helicopter range and discussing airborne rescue before the winds worsen as predicted; visibility and pilot safety are additional issues. 

The Polarstern lost a helicopter pilot in Antarctica a few years back with multiple scientists injured.

It's not clear what to measure to show/not show the ice is shearing, compacting and diverging more than it did, to what extents this year is natural and unnatural variation off a weak 2018-19 winter, and whether the mechanical properties of the ice have deteriorated.

We've previously looked at the August, September and early October history of this floe. Basically it was newly formed from collisions and a barely consolidated mess as late as the Oct 2nd S1AB. Still, what were they going to do after eight years of planning and grant-writing. Wait for the ice to freeze solid, then set up in the dark?

Up thread, I laid out Plan B options. The best idea is probably to pull in all the remote equipment, set out more buoys from the relief icebreaker arriving, draw up the ice anchors, squirrel the shp around make an open patch of water, point the bow (where the key instruments are) into the wind to avoid the massive air pollution affecting them now, and change locations under powered drift.
Title: Re: MOSAiC news
Post by: gerontocrat on December 03, 2019, 01:33:24 PM
I guess the MOSAIC expedition is having another rotten day.
Title: Re: MOSAiC news
Post by: uniquorn on December 03, 2019, 02:25:41 PM
It's not clear what to measure if the ice is shearing, compacting and diverging more than it did
Had a look at osisaf for today but it only goes back to 2015 and wouldn't be representative (ctr). Is there a monthly drift somewhere that might give an overview of possible increase in mobility over the years. (or average the arrows over a month somehow?)

A month of meandering mosaic drift, nov2-dec3. Another acceleration yesterday. ~31days in 150 frames.

Woods Hole Oceanographic Institution, owners of itp102, part of the mosaic buoy network, give a nice overview of drift on their site and at the moment mosaic align quite well with annual drift.
Title: Re: MOSAiC news
Post by: Tor Bejnar on December 03, 2019, 03:20:54 PM
The 'dance' is beautiful to watch.

 Is there some way to indicate how much (if any) the distance between buoys changes over time?
Title: Re: MOSAiC news
Post by: A-Team on December 03, 2019, 03:34:04 PM
Is there some way to indicate how much (if any) the distance between buoys changes over time?
Yes. Put the three buoy lat lon columns in a spreadsheet, making sure their half-hour time stamps are in register. Add the haversine formula ( as 7th-9th columns to calculate sides. Add a 10th column that sums these to a triangle perimeter. Use the SSS formula sqRT (s(s-a)(s-b)(s-c) with s the semi-perimeter for the area. Draw each triangle using an online triangle tool, capture, bin-color in proportion to area, float as otherwise transparent layers and animate. YES YOU CAN

date   hour   lat-P201   lon-P201   lat-P204   lon-P204   lat-P207   lon-P207
01 12 19   03:00   85.9394   113.4152   85.9400   112.7791   86.0074   112.4806
01 12 19   02:30   85.9413   113.3999   85.9420   112.7633   86.0093   112.4640
01 12 19   02:00   85.9432   113.3855   85.9438   112.7479   86.0111   112.4486
01 12 19   01:30   85.9450   113.3719   85.9457   112.7335   86.0128   112.4341
01 12 19   01:00   85.9467   113.3608   85.9474   112.7194   86.0146   112.4214
01 12 19   24:30   85.9485   113.3505   85.9491   112.7078   86.0163   112.4103
01 12 19   24:00   85.9503   113.3405   85.9509   112.6973   86.0180   112.3994

The tool below will put your choice of inter-buoy distance along the bottom rescaled to a constant length. Then you can see the relative shape change in the other two sides.

average the ice motion arrows over a month somehow
In the past we have tried loading the month as grayscale in gimp and using the 'average layers' command on a duplicated stack (image menu). That gives a so-so wind rose at each grid point that could be compared year on year by image subtraction to give a 2015-19 animation.

It may be that OsiSaf ill-advisedly puts the center of the arrow over the grid point (as mosaic_multi does) instead of the tail. So we need to first redraw the arrows with no heads using the OsiSaf netCDF than no one can get to work. Alternatively Panoply (or command line) dumpNC would give numeric x,y values at grid points or regions of interest that could be passed on to Excel which has a good wind rose chart.

The next three days or so on GFS look like more of the same: moderately strong winds at a fixed bearing. Below, the png assumes a mid-range coriolis angle of 25º of ice movement CW to the direction of the wind. Zonal and meridional components r,θ = lat lon are shown for the 05:00Z nullschool of today roughly scaled to the cube of 100 hPa wind speed from comparing response at periods of constancy.

In three days time, my expectation is the Polarstern will drift to 86.2  121.9 (ie on 09:00 on 06 Dec 2019 according to sailwx tables). Thus 1/6th of the trip will be over without any real indication of Fram-ward transpolar drift.

Sentinel coverage of the Mosaic floe has resumed. Daily instability suggests very little of it is fit for purpose.

S1B  2019 12 03 T 0643  17  210  -17.1  86.0017  115.6685

Technical note: nullschool provides a clean 1º graticule over land if wind is set to none. AwiMet provides the green location circle. Setting the scale parameter to 3000 maximizes resolution. Longitude has been increasing by 0.05 deg/day over the last 24 hours but latitude by only 0.005, setting the wind scaling. (Mean recent change or tangent to the PS position curve could be determined more accurately with high resolution S1Ab or buoy data.)

The tangent vector is set by rotating to vertical using the Polarstern's current longitude, drawing a perfect horizontal, then rotating back. The wind direction is drawn as the tangent vector to the radial vector of the osculating circle to the curving wind sprite at the PS. Dropping the perpendiculars then gives the desired breakdown of motion in terms of lat,lon. Here taking the ratio of r,θ component vectors causes the wind scaling factor to drop out.
Title: Re: MOSAiC news
Post by: uniquorn on December 04, 2019, 03:27:36 PM
drift update, 3 close Pbuoys, ~7days in 50frames. Retracing at speed.
small steps, Tor, small steps :)
edit: updated below
Title: Re: MOSAiC news
Post by: A-Team on December 04, 2019, 04:33:17 PM
take the time to get it right Tor.
Given the very small patch occupied by the three buoys, it would be ok to forget the WGS84 ellipsoid and for that matter the spherical earth and just work on its tangent plane at a buoy triangle centroid. So, using the buoy positions as lat, lon = r,θ of plane polar coordinates = rcosθ, rsinθ (lat in S1AB pixels, lon in radians) = x,y cartesian, it is a matter for high school trigonometry.

What about using mean wind speeds from reanalysis as a proxy for ice motion to make a month on month comparison to Nov 2019? That data is readily available quite a ways back. We could wonder how accurate it is for the Arctic Ocean given the near-total lack of instrumentation but that might not much affect anomaly or trend estimations.

However wx'ers steer clear of near-surface wind wind prediction whereas that is precisely where wind stress on the ice arises. And for that, ridges and floe edges (aka freeboard, thickness) provide the primary frictional surfaces. How much do we know about these even in the Polarstern year? Next to nothing. Assuming they're the same defeats the whole purpose of the wind proxy: more wind but less surface friction would look very similar to less wind and more friction.

Three Sentinel-1B came in this morning. The Polarstern ducks being all in a row already, there wasn't much to do (1st image) except translate them sideways to tomorrow's prediction based on strong steady winds forecast at GFS-null.

The animation of the 3x close-ups do not indicate any rifting or ridging though the turmoil continues on the Mosaic ice camp area (which was a jumble of unconsolidated blocks to begin with). The faint white diagonal indicates the direction of travel to left.

However the ship is entering an area in the anti-cyclone lee of SZ, suggesting ridging if winds converge, or shear if wind speeds differ (4th image). Winds faster than 14 m/s are considered gale force (table below). Use keyboard 'k' to advance 3 hrs, 'shift-k' to advance 24 hrs on GFS:,90.00,3000/loc=118.600,86.100

We have no accurate way of placing the Polarstern (green circle) latitude forward on GFS predictions, a significant issue given sustained wind speeds. Sailwx sishowing the ship a whole degree of longitude east in the 9 hours since the last S1AB):

  86.1  119.1 19-12-04 15:00   16  230    -16.7
  86.1  118.1 19-12-04 06:00   12  240    -14.7

D 2019 12 04 T 0546   86.0937   118.1062 which is 434.4 km from Pole
C 2019 12 04 T 0408   86.0891   117.9333 which is 434.9 km from Pole
B 2019 12 04 T 0230   86.0839   117.7657 which is 435.5 km from Pole
A 2019 12 03 T 0643   86.0017   115.6685 which is 444.6 km from Pole

DC Distance:   1.411 km in 1.633 hrs for 0.864 km/hr or 20.7 km/day
Initial bearing:   248° 20′ 42″
Final bearing:   248° 10′ 21″

CB Distance:     1.397 km in 1.633 hrs for 0.855  km/hr or 20.5 km/day
Initial bearing:   245° 38′ 14″
Final bearing:   245° 28′ 12″

BA Distance:   18.51 km in 19.78 hrs for 0.934  km/hr or 22.4 km/day
Initial bearing:   239° 54′ 19″
Final bearing:   237° 48′ 47″

DA Distance:   21.3 km in 22.55 hrs for 0.945 km/hr or 22.7 km/day
Initial bearing:   242° 31′ 00″
Final bearing:   240° 05′ 05″
Title: Re: MOSAiC news
Post by: A-Team on December 05, 2019, 01:58:38 PM
The Polarstern continues to drift very rapidly east (ie the wrong way) and slowly north. The winds have been in the double digits for the last 61 hours, averaging a 14 m/s gale force push at~50 km/hr. The direction of the wind has been remarkably steady at 240º.

GFS-null shows this drift will continue for 2-3 days as the anti-cyclone center elongates to the north as it dissipates. Wind vector constancy presents an opportunity to determine the 'Nansen angle' of ice drift relative to wind under these conditions and to predict Polarstern drift a few days out.

The issues here are the ground accuracy of GFS and the optimum scale for angle measurements as nullschool. The url can be fed the nrt position data from sailwx, currently 86.1  121.1  11:00   14  240. At maximum resolution, a rapidly moving Polarstern moves noticeably on GFS nullscape.

Here position-specific daily (or 3-hour) urls at the time of S1AB, say 05:00z can be manufactured by a simple merger of AWImet and any initial GFS url. It would be great to have this back to the mooring date of Oct 4th at a couple of scales as an mp4. Note gimp side panel thumbnails show high velocity winds at a glance. Production at 3 hr intervals would require an automated procedure as 8 per day * 60 days * 2 scales = 960 is out of reach of manual methods.
=-45,90,3000/    Greenland down, north pole centered, scale
loc=121.1,86.100 longitude and latitude of Polarstern

The two new Dec 5th Sentinels show continuing turmoil within the Mosaic experimental area. A relief icebreaker is on its way, sort of. There is currently a 949 hPa cyclone in the north Atlantic between this ship and the Arctic Ocean.

Quite a few scientists from leg 1 will be returning to shore. Leg 2 is seen as the most difficult because of unrelenting cold, darkness and wind. It appears a new communications officer is coming on board; that might help us stay better informed.
Title: Re: MOSAiC news
Post by: gerontocrat on December 05, 2019, 06:41:22 PM
It seems the Russian icebreaker, "Kapitan Dranitsyn" has now left port  (Tromso) and is on its way.

It also seems it will divert, if necessary, to help getting Horn and Ousland off the ice, and maybe rescue  the Norwegian research ship «Lance» which has got stuck trying to get to the two men.
A Russian icebreaker set out from Tromsø with course for ice-locked German research ship
The «Kapitan Dranitsyn» is bringing equipment, supplies and 95 researchers to the «Polarstern» as part of great international research expedition MOSAiC.

'Tis the "Law of the Sea" - both written & unwritten.
Title: Re: MOSAiC news
Post by: A-Team on December 05, 2019, 08:23:00 PM
The whole ending strikes me as highly contrived, all about filming a meet-up with two buddies and later them eating ribs and french chocolate. The Lance has a helicopter pad but they are not using it so the adventurers will be able to say they went boat to boat per the original plan.

The tent camp is also well within reach and capabilities of the Svalbard helicopter service that extracted the crew from the grounding in the Hinlopen Strait last December.

The Lance does not really have to chops for this job and keeps getting frozen in the 30 cm ice but they are scripted to moor along an ice edge so the two do not have to be seen being picked up from a zodiac even though they are having to be rescued as they don't have the food or fuel to continue under current ice conditions and more weeks of unfavorable floe drift.

There is a Norwegian icebreaker at the scene but they are not using it. The Polerstern's relief icebreaker is not likely to be headed towards Svalbard -- way out their way and through more ice than necessary. These ships have all turned off their GPS beacons; sailwx is only receiving the Polerstern's.

Updates -- and some pointed questions about an actual purpose for the trip -- can be found in the comment section at this Norwegian site which updates almost hourly:

Just before Lance left Longyearbyen, a research ship also left north. I see on Marine traffic that this ship is on standby on the ice (on starboard side of Lance), probably be the new state-of-the-art icebreaker for the Norwegian Polar Institute, "Crown Prince Haakon" a research assignment in the area and can contribute if necessary. The name may be icebreaker Haakon Magnus "is located just to the east of you, can't they break a real trap for you?

How much does it mean for the expedition to go "unsupported", which is not possible with post-supplies? And how do they manage to meet in the icy, dark and snowstorm. Even with GPS and satellite phones, this must be a major challenge. The two teams of polar explorers have agreed on a common point on GPS that they both are heading towards.

Bengt Rotmo and Aleksander Gamme, friends coming on foot to the tent camp, have emergency rockets and a signal gun too, so they can use it to show where they are. There is a doctor on board the Lance though no issues are expected.
Title: Re: MOSAiC news
Post by: uniquorn on December 05, 2019, 10:49:40 PM
drift update, 3 buoys close to PS, ~8days in 70frames.
Title: Re: MOSAiC news
Post by: A-Team on December 06, 2019, 12:38:31 PM
Some large scale north-south extensional fissures have opened up, a long 600m wide crack to the east of the Polarstern and a (so far) smaller one right through the Mosaic floe a few tens of meters west of the ship.

Even a small displacement in Ice Camp disrupts power lines, towers, generators, experimental equipment and repair access. Here the lead is approximately 100m wide (2-3 pixels on S1AB 40m).

This followed 72 straight hours of wind speeds in excess of 10 m/s at the ship's location, attributable to its position in the north-central winds of a persistent anti-cyclone centered in the New Siberian Islands.

On the next post, the relevant GFS nullschool sequence shows that sharp curvature in the applied wind stress from the tightly coiled anti-cyclone was incompatible with increasingly brittle ice, which then shattered along north-south lines to accommodate to applied forces.

The 05:30 scene will apparently be the only S1AB today as the 07:00 orbital pass was either not taken or suppressed. It is hard to believe that both A and B satellites would have higher scheduling priorities at such an obscure location during a dramatic moment in an historic Arctic expedition. Surely AWI has closer connections to schedulers at ESA Copernicus than foreign researchers; eight years of planning went into Mosaic.

In any event, we don't know if the 05:30 caught the beginning, end or middle of the lead opening. It could be growing to the size of the one to the east; alternatively it may have peaked earlier and now be closing. Previous images show that this is not a new fault but rather reactivation of an older lead.

Note a second fissure comes in from the west (3rd image). This too has opened and closed repeatedly over the last two months.

The final image shows a rare cloud-free swath of heat map of the area around the Polarstern a few days back. The white lines are leads that, despite being frozen over, still leak more heat to the atmosphere than surrounding thicker ice and so are brighter when imaged in the infrared.

Neither lead can be attributed to the PS and AF icebreakers maneuvering about during the initial mooring to the Mosaic floe, though we might wonder how the relief icebreaker Kapitan Dranitsyn will get in close enough to refuel the Polarstern.

Insulting official expedition communications from 'Follow Mosaic' feature inane pictures of omelets and baked goods from the Polarstern kitchen, along the lines of arranging deck chairs on the Titanic. Shupe's AGU blog, the only real source of information, has not been updated since November 18th. It has a nine day lag between its writing and its posting.

A new Helmholtz post on PS site mitigation appeared on Dec 4th but seems dated, non-specific and smiley-faced about disruptive floe events, insuperable problems obtaining data continuity over a year and tainting of air quality data by the ship itself. (On past expeditions, the PS stayed pointed into the wind, allowing fresh air to reach bow instruments).  One interesting point however about wastewater:

When it comes to the outlet for our filtered wastewater (technically clean water), a pump system was installed on Polarstern that reintroduces the salt previously removed from it, before discharging the water at a depth of ca. 150 m. The times at which these ‘dumps’ are made are documented, allowing any potential influences on them to be identified after the fact.

By far the best reportage is coming from Martha Henriques at BBC. The Dec 3rd post links back to the others. Byron Bloomquist of CIRES NOAA is also posting detailed damate reports. AWI, the expedition lead, gives out no information whatsoever.

Markus Rex of AWI, expedition leader, shows me the trajectory of the drift so far on a screen in the Red Saloon, one of the ship’s common rooms. There is a pattern in the meandering line on the screen that shows one reason that cracks and pressure ridges have been appearing in the camp.

“You see these cycles here?” he traces a line in the shape of a scalloped edge. “It’s fast here, then it’s always slow, slow, slow.” He stops at a pinch point on the line. “These are the points when we get the high pressure.” That’s when the floe is twisted and pulled in different directions.

At least there is some predictability in these cycles but still, but as Rex watches the screen inside the Red Saloon, it’s clear that there is little the team can do but hope the damage to instruments and infrastructure each time won’t be too great.
Title: Re: MOSAiC news
Post by: gerontocrat on December 06, 2019, 01:48:34 PM
To me it looks like the MOSAIC project has had some windy times but not a real humdinger. So I did a google to see if they should expect one.

Perhaps they should, especially in this month.
Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean

The strongest storms in the Arctic Ocean typically occur during winter and originate from the North Atlantic Ocean1,2 (Fig. 1). The number and intensity of Arctic winter storms has increased over the period 1979–2016. These storms often generate strong southerly winds that transport heat and moisture into the Arctic from the mid-latitudes, contributing to record breaking winter temperatures.
Extreme cyclone events in the Arctic: Wintertime variability and trends

Typically 20–40 extreme cyclone events (sometimes called 'weather bombs') occur in the Arctic North Atlantic per winter season, with an increasing trend of 6 events/decade over 1979–2015, according to 6 hourly station data from Ny-Ålesund. This increased frequency of extreme cyclones is consistent with observed significant winter warming, indicating that the meridional heat and moisture transport they bring is a factor in rising temperatures in the region. The winter trend in extreme cyclones is dominated by a positive monthly trend of about 3–4 events/decade in November–December, due mainly to an increasing persistence of extreme cyclone events. A negative trend in January opposes this, while there is no significant trend in February.
Title: Re: MOSAiC news
Post by: A-Team on December 06, 2019, 05:08:52 PM
Below, a summary of weekly blog posts from Byron Blomquist, CIRES and NOAA. The event this morning appears catastrophic even relative to earlier havoc at the Mosaic floe. An update can be expected Monday. Dec 9th.

The scientists' persistence to stay operational under difficult weather and ice conditions is only to be applauded but as with a poker hand, there is a time to hold 'em and a time to fold 'em.

The event this morning may prove a tipping point. The original plan, conceived eight years ago, is no longer viable in the ice of today. It is time for Plan B.

GFS foresees a lull for the next five day: slow drift north but in the direction of Ellesmere Island, not the Fram Strait.

“December 2. The Dranitzyn left the coast of Norway yesterday to begin the transit to our location and should arrive within a week to 10 days. AWI estimates it will then take about 5 days to transfer ~50 tons of cargo between the two vessels and pump over the fuel, weather conditions permitting. We were not able to accomplish everything we planned for leg 1 having to overcome a series of setbacks related to ice dynamics.

The route to Met City was reestablished over the past week and the main power lines reconnected, so most of the instrumentation there is back on line. The ship's machinists repaired damage to the collapsed 30m met mast and we hope to reinstall it as a 23m mast sometime next week.

Air sampling from the bow is often good for several days running, then unsuitable for several days as the wind direction shifts to the stern of the ship.

The anemometers, CO2/CH4 flux system, fast ozone, slow ozone, NOx, GCMS, and mercury instruments have all been running well. The DMS mass spectrometer ran for a few weeks, but a power supply failure will keep this system off line until leg 4.
Nov 25, 2019. The passage of two arctic cyclones last weekend was a unique opportunity to make atmospheric observations of a poorly understood weather system. There were no major shifts in the ice pack over the last several days but the situation remains dynamic, with leads opening and closing on a daily basis.

The remote sensing site has been dismantled and will be rebuilt at a new site. The ROV site is partially operating on generator power. The Ocean City site was dismantled and moved to avoid an ice ridge, but is mostly operational again.

The situation at Met City is tenuous. Met City is still without a power line but instruments on the tower are operating part of each day on generator power and we've been able to access the site twice daily to refuel. It is sometimes possible to reach Met City by snow machine, but often access is by foot only.

The exact route changes daily, depending on ice conditions. Met City is currently only about 400m from the ship, but the route over ice is probably closer to 1 km. Our measurements there are still shutdown and we don't have a good estimate yet for when the power and data lines will be reestablished.

After the large shift in the ice floe on 19 Nov, the Met City, ROV and remote sensing sites moved about 600m to the SE, across the bow of the ship. Met City is now located directly in front of the bow and the remote sensing site will be reestablished in this same general area. Ice in front of the ship is now a complex system of blocks and ridges. The ROV site is now off the port quarter of the bow.

The formerly compact Central Observatory site now spreads over a much greater area and the bow of the ship is largely surrounded by on-ice infrastructure. If the ice solidifies in this state, this will be the arrangement for the remainder of the project. This will impact the clean wind sector for measurements from the bow of the ship, but there should still be many hours per day with minimal activity on the ice.

November 15-17. A powerful winter storm blew through the scientific cities set up on the ice around the ship. Intense winds tore new cracks in the ice floe next to the ship, sending some ice-based instruments adrift. It’s possible that the floe will drift back together and freeze again. I think about the word “mosaic” and how it implies a breaking in order to be put back together.

Eventually the drift slowed down. The instruments moved in a U-shape around the bow of the ship. ROV Oasis is now off to the left. Remote Sensing not far by. Met City is directly in front of the bow. Ocean City and Balloon Town stayed in relatively the same position, but a long lead opened directly next to their tents.

The Atmosphere Team’s flux stations, part of the distributed network, are doing great, overall, although we had one disruption that involved a polar bear. We have snapped cables and a dismembered exhaust system to repair. We are working to rig new connectors and cables, and have ordered a new exhaust pipe that will hopefully arrive with the next leg of participants in December.

Due to a major storm in the last few days, we have also had lots of cracks around the ice, and one has opened up so wide that in order to get to our instruments, one has to use a kayak to cross to the other side.

The 30 meter tower has tipped over. An assessment of the instruments and damage done to the tower are still on-going. Our other 11 meter tower is still standing tall, but another smaller crack has opened beneath one of the guy-wires that holds up the tower.

Nov 19, 2019. The last several days have seen some dramatic developments and some setbacks.  On Saturday a strong arctic cyclone moved through the area, bringing sustained winds up to 20 m/s for many hours, first in an westerly direction, then veering to northerly. Our drift rate increased to > 0.5 kts to the E and then to the S, at one point up to 0.8 kts. We are now well S of our position a week ago and are once again on a track toward Siberia.

The large multiyear floe which was selected as the backbone of our Central Observatory split in two on Sunday, with a significant shear zone developing just in front of the ship in a port-starboard direction.

This lead has opened and closed a few times over the past 48 hours and the shear between the two halves is currently offset by as much as 70-100 m. The block with Met City, ROV City and the Remote Sensing Site are on the opposite side of the crack and a large ice ridge is developing between Remote Sensing and Ocean City.

The Remote Sensing site was heavily damaged by ice movement and a number of large instruments were moved to safety on Sunday. The site will need to be reestablished at another location when the situation stabilizes.

The power and data links to Met City and all other sites on the opposite side of the lead were severed early AM on Sunday. Further ice movement brought down the 30m met tower at Met City early this morning. Otherwise, most of the equipment installed at Met City is intact and appears to be on stable ice, but only a few instruments are operating, powered by intermittent backup generator supply.

Our CO2/CH4 flux system at Met City is down and will not operate until ship power is restored to the site. Met City was originally located about 800m off the starboard beam of the ship at a 2 o'clock bearing, but as of today is drifting toward the 1 o'clock position. Because the ice is still moving we do not know when power and normal operations will be restored.”
Title: Re: MOSAiC news
Post by: blumenkraft on December 06, 2019, 05:43:00 PM
^^ There might be the answer why we don't get more data... :(
Title: Re: MOSAiC news
Post by: A-Team on December 06, 2019, 07:34:57 PM
why we don't get open data from Polerstern / Mosaic?
I looked into a Freedom of Information request for the ship's log, gps location and heading at ten minute intervals and so on. I have done these requests before in the US, followed by successful but time-wasting lawsuits when inevitably they don't comply.

This probably wouldn't go anywhere with NSF grantees like Shupe and Blomquist who are already posting quite a bit of timely disclosure in their realms. The US kicked in $26m; grants will be monitored.
Now a FOIA could get some BS stonewalling such grantees have a right to first use of experimental data, at their leisure (ie 2023 in Mosaic planning documents).

However after much commotion, NIH at least requires immediate disclosure in genomic DNA sequencing. There, a robotic sequencer ftp's its reads directly in real time to a public web archive, just like the 92 Mosaic buoys do today including those of AWI.

Here Mosaic is doing shotgun environmental sequencing and any US grantees would fall under compliance obligations. The original rationale was human health research should not be delayed; the same could be said of planetary health.

Germany/AWI of course does not fall under US domestic law but they may have something similar on the books. AWI presumably owns the navigational instruments on the bridge; on previous expeditions -- but not here, no explanation --  has always published a detailed weekly Polarstern report. It would probably take a filing from a German citizen or reporter to meet the requirement of standing.

What gets me is the deliberate dumbing down of the Polarstern's GPS location. That required a deliberate decision to actively intervene because in factory default mode and in actual onboard use, the instrument would be sending 5 decimal points instead of one. No one navigates through Arctic sea ice on 1 dp.

It all reminds me of the EA189 engine at the center of the Dieselgate scandal that continues even today with the successor EA288.

We are to believe that AWI and 600 polar scientists were surprised to learn upon arrival that the best floe around was only 30-50 cm thick instead of 1.2m. Oh sure.

A satellite unknown to science measured ice thinness during late summer but got it wrong? They made that one up.

A $150m experiment and they didn't have an old tramp steamer out there in late August drilling floes? Not to be believed.

Russianss ran 5 tourist trips to the north pole in late summer but didn't tell AWI partners about ice conditions or why they pulled the plug on Borneo? Highly implausible.

AWI knew perfectly well in advance about the problems ahead, just like VW knew about its NOx problem. Why else would you turn off ship beacons and dumb down its GPS upon leaving port?
Title: Re: MOSAiC news
Post by: uniquorn on December 06, 2019, 08:40:31 PM
Drift comparison of p201, p204 and p207 setting the start of each track in the same place on oct11. An attempt to show distance change between buoys over time until something better comes along.
tech note: data missing on oct31 as mentioned upthread
Title: Re: MOSAiC news
Post by: blumenkraft on December 07, 2019, 08:25:37 AM
Translation of the Arctic Drift Podcast #7 - Sturm
Release Date: 03 Dec 2019



Arctic drift,  the audio log book.

The first big storm has afflicted the MOSAIC expedition in the Arctic. The ice camp around the icebreaker Polarstern was exposed to a hours lasting storm with wind speeds up to 9 (Beaufort scale). The head of expedition Markus Rex talks about the repercussions of the storm.

<Markus Rex>

Yes, last weekend we had our first big storm with harsh wind speeds up to 20 meters per second. Such a hefty blow. While the storm was forming we could see that a big crack developing but then the sight was too bad to see it. The next night the storm had clearly left some marks on the ice. The crack that developed the night before was now a shear zone, a fault zone with smaller floes and pieces of ice. All of a sudden, the whole other half of the camp magically drifted with high speed eastwards. It looked like a train scrolling by. First ROV city, then remote sensing site, then MET city passed the bow and then they vanished in the dark. This is, of course, a drastic event for our camp. After 600 meters offset it stopped.


Because of the storm and the offset of the ice also the route of drift has changed. The Polarstern is still frozen to an ice floe and moves without its own engines.

<Markus Rex>

Since the storm, we moved north towards the pole but we will have westerlies according to the forecast. Which means that we are moving along the western part of our drift scenario. This is all still in a margin where we feel good about but we would like to come north more quickly. The overall way we made so far is in the upper expected range.


Also, the infrastructure of the camp is partly damaged. Power and data cables are cut and need to be repaired. Until this is done fewer data can be gathered.

<Markus Rex>

Since the shear zone moved right through our camp and cut power lines, we installed emergency generators to power the equipment. But we are on a reduced measurement schedule. We are now in the process of developing a new town plan. We know what should be located where now and in the next days after we see some stabilisation we will deploy the new power and data infrastructure.

The future town plan will differ from what we have now. At the moment all the sites are in a linear line along the ice and a pressure ridge easily to protect with a tripwire against polar bears. We will though, out of necessity, have a radial layout in the future. This will be harder to protect against polar bears, but this is what nature has given us and we will live with it.

Even though the negative aspects of this storm are plenty, there are also positive ones. Never before where measurements made from the inside of an Arctic storm so intensely.

<Markus Rex>

From a science perspective, such a storm is a thrilling event. This is why we are here. We want to find out how the weather systems in the Arctic work together. We have complete measurements of multiple parameters from before, during and after the storm. Energy flow, heat flux,  snow thickness, radiation, what it did to the ice. This is a unique dataset and we are amazed when we look at it. This will allow us to improve weather models. Yes, it's problematic that we will have a new town layout and that we have to rebuild a lot, but this data is what we are here for.


Fortunately, there are parts of the camp that are undamaged and work fine.

<Markus Rex>

The storm has affected almost all of our sites but one. The core of our observatory, the Balloon town, which we call the town hall, is still in the same place and can be used as before even though the landscape has changed dramatically. We now have a big pressure ridge in the background and a crack in the ice behind it. I would say this has become a very attractive site with direct water access and mountains. And we can still launch our balloon.

The balloon can, of course, only be launched with moderate wind speeds, so during the storm, the balloon took no measurements.


And again, this week a polar bear family visited.

<Markus Rex>

A mother with her two almost adult curbs came by. They tripped over the wire which caused two flare bombs to start. That startled them a little and the mother became cautious. They circumvented the camp in a wide bow and they did what they are supposed to do - move along in the dark. But while they were near one of the curbs couldn't resist exploring everything it could. It tried to overturn every flag and play with everything. The mother returned a few times to collect the imp. The other curb stayed with the mother all the time. You could see the curbs were only one year old but had their own personality already.


When the work is done, the scientist have time for personal activities. May it be sports or just watching northern lights.

<Markus Rex>

Friday night we have opened the ice for personal use. Some played with the frisbee disc,  a soccer game took place, some went off with skis and made a tour. Of course, it was black outside, but a black with a few northern lights. We are too far north to see plenty of them, but sometimes we have them.
Title: Re: MOSAiC news
Post by: psymmo7 on December 07, 2019, 09:46:00 AM
Vielen Dank, Blumenkraft!
I think you are doing a very valuable job making this information on Mosaic accessible to the English-speaking world. If you can't manage to do it in future, let me know. I'm an English native speaker, but I'm fluent in German.
Title: Re: MOSAiC news
Post by: blumenkraft on December 07, 2019, 11:30:51 AM
Vielen Dank, Blumenkraft!
I think you are doing a very valuable job making this information accessible

Thank you! :D

If you can't manage to do it in future, let me know.

Well, the translation took more time than i anticipated. I wasn't too sure i can keep it up like that. Perhaps a list of bullet points is easier to do and gives the reader the same Infos.

The new one (episode 8 ) is in my podcatcher now and i planned to translate it tomorrow in the bullet list form. If you want to do the next one (episode 9) that would be cool. I can help of course if you want. :)
Title: Re: MOSAiC news
Post by: blumenkraft on December 07, 2019, 12:04:10 PM
Don't think this was posted before. Makes sense to have a picture of the site when reading the podcast.

Link >>
Title: Re: MOSAiC news
Post by: A-Team on December 07, 2019, 12:13:05 PM
That would be the 03 Dec 19 podcast though which of several storms is hard to say. Note 'pressure rig' translates to 'pressure ridge'. The follow-up 'Nach dem Sturm' is dated Dec 6th but I am quite certain it does not address the worst storm yet of the same date.

We remained throttled down to 1 Sentinel per day out of the 8 daily orbits passing over the Polarstern. Today the ship was just barely included on the far eastern edge of the 02:45 image. The Mosaic floe is so distorted after the massive lead openings seen at 05:30 the previous day that it is hardly recognizable, though its identity is certain from neighboring floe context.

This event likely undid much their previous ice camp restoration as well as bringing all kinds of new disruptions. The weather will be very mild the next five days so there will be an opportunity to catch up. However, going by past years, there is no reason to believe this will be the last severe anti-cyclone of the winter, on the contrary (see gerontocrat #368 above).

The ice is slowly getting thicker according to the 4 Simb3 buoys which might help subdue ice dynamics at the Ice Camp. As the ice becomes more brittle with deeper cold, that will change the character of disruptive events to less plastic fractures.

The two images below show what has happened. As noted above, the ship was situated at a hairpin of sharp wind curvature; the stress was too high at prevailing wind speeds for rigid ice to go with the flow.

I am seeing a lot of misunderstandings about ice advection in the Arctic Ocean on the part of the atmospheric physicists. Going north will never get them to the Fram Strait on the expedition time frame because a gigantic immobile block of multi-year ice is in the way.

They need to drift west to catch the circumpolar drift ('around') which is too often confused with less frequent transpolar drift ('across'). Flow has largely been zonal in recent years, not meridional (over the pole). Last year's displacement of the FYI/MYi boundary line was somewhat exceptional, with ice on the NP-Wrangel line passing over the pole (but not getting far).

So far this year, ice in the central Arctic is just milling about, the Polerstern's aimless drift is representative of a far larger region. You can see this just animating Ascat masked by Amsr2; we have that on another forum for the last nine complete years.
Title: Re: MOSAiC news
Post by: blumenkraft on December 07, 2019, 12:16:35 PM
Thanks a lot, A-Team! Fixed it.

And yes, the timeline you point out is correct. I added it to the OP.
Title: Re: MOSAiC news
Post by: A-Team on December 07, 2019, 01:05:22 PM
makes sense to have a picture of the site
That one is a mirror image, an old conceptual layout. We do have the original site plan from the 126 page planning document up-forum as well as a later as-built map in radial coordinates centered on the ship. We also have the modified site plan they just released up-forum; it is no longer radial and quite blurry at all the places it has been posted.

None of these maps are at all appropriate to the pending redeployment of the Ice Camp -- if there is one -- after yesterday's big rearrangement.
Title: Re: MOSAiC news
Post by: uniquorn on December 07, 2019, 02:07:30 PM
Rapid drift to a grinding halt for direction change. Almost a handbrake turn.

edit: added a drift comparison. Spatially quite similar though one or more buoys appear to temporarily race ahead during the more rapid drift. It's possible that could be an artifact of generating the animations separately though.
Title: Re: MOSAiC news
Post by: gerontocrat on December 07, 2019, 03:14:34 PM
The weather will be very mild the next five days so there will be an opportunity to catch up.

Not so sure about that - no storm but windy enough for discomfort given the parlous state of the floe & environs?

Nullschool says 30 kmh wind tomorrow.
Gradual reduction over the next few days to 20 kmh and gradual direction change from 135 to 180o
Title: Re: MOSAiC news
Post by: psymmo7 on December 07, 2019, 04:35:10 PM
Hi Blumencraft
Leave Episode9 to me.
Glad to be of assistance.
Title: Re: MOSAiC news
Post by: A-Team on December 07, 2019, 06:15:34 PM
Leave Episode9 to me
Thanks, helpful!
Not so sure about that - no storm but windy enough for discomfort given the parlous state of the floe & environs?
Maybe but there is no double digit velocity in sight on GFS (the hourly ship wx uses m/s). All the major events so far have been at sustained gale force winds, 14 m/s or 50 km/hr.

Since the last S1AB, the ice has presumably had a chance to consolidate because of the calmest conditions yet of the expedition.

  86.2  122.1 19-12-07 10:00  4  120  -21.2  1022.1
  86.2  122.2 19-12-07 09:00  4  110  -21.0  1023.0
  86.2  122.2 19-12-07 08:00  4  100  -20.8  1023.8
  86.2  122.2 19-12-07 06:00  3   90  -21.2  1025.0
  86.2  122.2 19-12-07 05:00  2   60  -20.2  1025.7
  86.2  122.2 19-12-07 04:00  2   50  -18.3  1026.2
  86.2  122.2 19-12-07 03:00  2   70  -21.1  1027.0
  86.2  122.2 19-12-07 02:00  1   80  -21.7  1027.5
  86.1  122.2 19-12-07 00:00  2  120  -22.3  1028.7
  86.1  122.3 19-12-06 23:00  3  100  -23.1  1029.2
  86.1  122.3 19-12-06 22:00  3  100  -23.2  1029.9
  86.1  122.3 19-12-06 21:00  2   90  -23.6  1030.4
  86.1  122.3 19-12-06 20:00  2   80  -24.2  1031.0
  86.1  122.3 19-12-06 19:00  0  360  -24.5  1031.5
  86.1  122.3 19-12-06 18:00  0  360  -24.9  1032.0
  86.1  122.3 19-12-06 17:00  1  280  -25.3  1032.1
  86.1  122.3 19-12-06 16:00  3  260  -25.5  1032.6
  86.1  122.3 19-12-06 15:00  3  250  -25.9  1032.9
  86.1  122.3 19-12-06 14:00  4  260  -26.0  1033.2
  86.1  122.3 19-12-06 10:00  6  260  -25.7  1034.4
  86.1  122.3 19-12-06 09:00  5  260  -25.4  1034.4
  86.1  122.3 19-12-06 08:00  6  260  -25.2  1034.3
  86.1  122.2 19-12-06 07:00  6  260  -25.1  1034.0

That's because wind stress on the ice is not linear but grows roughly as the cube. So upcoming 7 m/s winds forces will provide only 1/27 (4%) the stress of peak 21 m/s winds seen so far.

In order to use 3-hour nullschool wind, the future position of the ship won't be at where it is today so the wind reading will be at the old location isn't applicable unless the new location can be predicted and the green circle repositioned.

However the main thing to look for at GFS nullschool is uniformity of the wind currently coming up in parallel constant-color sprites from the south. It is really abrupt changes in direction, speed and above all, curvature, convergence and divergence of the sprite lines that forecast ice disruption.

In other words, look at time series deltas using the 3000 scale in HD (high density) at the most recent ship wx position. It is these cyclones passing overhead that really check all the boxes.

Right now, the most up to date GFS with known PS position shows elements that would be problematic for the Mosaic floe, just not at very low wind speed.

Best practice with nullschool is to embed the url and popup in the image itself which just takes a couple of clicks past the screenshot.

As we've seen, not a day goes by without some apparent rearrangement of the recently formed ice jumble of the Ice Camp. Some of this may be attributable to satellite viewing angle or changing surface salinity rather than actual ice movement.

Pressure ridges and open leads are not always within satellite resolution. For example, a 10 cm crack and slight shear that took down the met tower guy wire is not observable on Sentinel.

Further, we don't know anything about current sensitivity -- is the floe so damaged now that it is preconditioned to the point that minor ice stress now has an effect?

Sometimes obscure changes at the Ice Camp cause major damage while major upheavals might not actually affect experimental areas. I wonder how much those onboard know about real time floe distortion away from the ship -- we are too high but they are too low for a good view.

They have done two fly-overs with lidar that we know of; only one was released but with flattened overlays. Otherwise it is dark and no one is allowed off the safety perimeter, all the more so since it had to be linearized.

While the ship does have forward-looking ice radar on the bridge, being moored on the starboard side with the Ice Camp at right angles and more to the ship axis may block a full assessment. In any event, none of that radar has been streamed our way despite the ship's fast internet. Mostly they are concerned with continuity of data collection.

That hasn't been great to date despite incredible efforts to keep instruments up and running.

Secondarily, they are concerned about evolution of a single floe over a year. That is already off the table as an attainable objective.
Title: Re: MOSAiC news
Post by: uniquorn on December 08, 2019, 11:53:06 AM
Drift update.
Title: Re: MOSAiC news
Post by: blumenkraft on December 08, 2019, 02:45:14 PM
Translation of the Arctic Drift Podcast #8 - (Nach dem Sturm)  After the Storm
Release Date: 06 Dec 2019


Arctic Drift, the audio log book.

<Markus Rex>

In the last weeks, we've made some circles around here. We moved north, south, west, and east but netted not much way. At the moment we are on the move towards north-east which we like. This puts us back towards the middle of our drift corridor. From here on it will likely, and averaged over weeks, going forward towards the north pole.


The MOSAIC expedition survived the storm that haunted them last week. In the meantime the infrastructure was rebuild and the scientists can do measurements as usual. The camp is a whole science town on the ice. The different science teams are assigned to different parts of the town. It's like districts. The site expands over several kilometres on the ice around the icebreaker Polarstern.

<Markus Rex>

As you know the hefty storm last week has caused some damage. The layout of our town has changed. Power lines were cut which forced us to switch to power generators causing the measurement equipment to not work fully. But we've built new ways and streets with provisional bridges to reach all the locations safely. We use pulks to overcome smaller cracks. We have reached a certain stability and are back in the game. Also, the 30-meter tall meteorologic mast that fell during the storm will be rebuilt soon.


The first phase of the expedition has almost concluded, which means that soon the first big swap of science personal and material will happen. Many of the scientists that are on the Polarstern since the end of September will leave the ship, new crew members will come aboard. At the moment icebreaker still can do the job of supporting the ship and swap people.

<Markus Rex>

The members of the first phase of the expedition will soon go home and a new team arrives. This happens via the Russian icebreaker Dranitsyn which left Tromsø on 27th of Nov. They had to wait out a storm on the northern coast of Norway though. Tomorrow night they are expected to leave their fjord. Travel time for them will be around ten days. The exchange of freight will take a few days and then they will already be on their way back.


In the future such swaps have to be done via aeroplane. The ice is getting thicker by the day and soon no ship will be able to reach them. In the next week, a runway will be built.

<Markus Rex>

For the first time, the ice has reached a kind of stability that you can consider building a runaway on it. The focus is on smaller planes right now so that you can evacuate people should there be a medical emergency. I checked the ice today and i think i found a suitable location. I think we will have an emergency runaway very soon. In the spring we will build it so that even bigger planes like an Antonov can land normally and not only with skis.


Wintertime in the Arctic doesn't only show in the growing ice thickness. While you see a lot of animals in the summertime, during the winter you only see them infrequently.

<Markus Rex>

The central Arctic in winter is a rather lifeless region. Normally, when you are on an expedition to the Arctic ice, you are seeing plenty of species. You see birds in the sky and seals on the ice all around in both of the Arctic regions. But now, here in the central Arctic during winter it's actually dead. Over weeks we don't see any animal and the ones we see are polar bears. But just recently a very cute polar fox with his black button eyes, white fur and that bushy tale came by, inspected things nervously but then quickly moved on.  It's not clear what their diet is. Often time polar foxes follow polar bear and nourish from what their friends left behind. Of course, we watched out for the foxes big bear friend but we couldn't see any. And since the fox was gone so quickly we assumed he followed his friend to not lose him.


In the next episode, you'll learn when the next crew members will come on board and who the next navigational chief is.

/me is handing over the baton to Psymmo :)

Title: Re: MOSAiC news
Post by: A-Team on December 08, 2019, 08:50:43 PM
This :) was written on Nov 27th but dated Dec 6th and does not address the most damaging storm of the trip on 03-06 Dec 2019. Pulks are sleds being used along with wooden palettes to bridge small leads. Presseisrücken are pressure ridges.

Co-leader Shupe is now over two weeks overdue on his weekly blog. Cires is not blogging the storm, Helmholtz quit in mid-October. Not substantive use is being made of twitter.

No news is a variant on fake news and historical revisionism: if they don't report the Dec 6th storm, it didn't happen. (Those satellites are sooooo annoying: 4 S1AB scenes today + clear Terra Modis.)

we will have an emergency runaway very soon. In the spring we will build it so that even bigger planes like an Antonov can land normally and not only with skis.
I sincerely doubt this looking at increasingly disheveled Mosaic floe which has not stabilized since the Dec 6th storm. Rex doesn't indicate where this runway will be located nor how thick the ice is; in the original plans, this was to be bladed by Piston Bullies in the flat dark areas (former melt ponds). However Mother Nature got there first.

If he is looking for volunteers to drive the bulldozers out on thin ice, like at Borneo, i am opting out. Surely Rex knows how slowly and unevenly ice thickens in the autumn; if not, a quick look over the ship's 100 mbps internet at the nearby Simb3 ice buoy graphs suffices. Those show 1.254 m snow + ice today -- the ice thickness they expected at mooring on Oct 5th some 66 days ago.

The Polarstern is looking at five days of inconsequential wind not strong enough to do any more damage. The ship will drift a bit north from its present record of 85.3º N but also a bit east from 121.2º E. We don't know at this point whether the weather will be calm or windy when the relief icebreaker arrives.

The Kapitan Dranitsyn's call sign is UCJP; the other numbers are IMO 7824405 and MMSI 273138300. We will be following the ship closely to see how much unavoidable damage and ridge/lead preconditioning it does in approaching the Polarstern. However it last reported on Dec-03 at 11:30 UTC, meaning it turned off its new state-of-the art navigation beacon after heading up from Murmansk.

This accomplishes nothing for Mosaic because we can still see the ship's stacks and tracks on Sentinel and RAMMB infra-red.

Contrary to their inept static drift model, this is not favorable for reaching wind fields that would bring them towards the Fram Strait. At high latitude, the ship will never get past that gigantic immobile block of MYI documented in the previous post.

The Polarstern is currently 1477 km from Svalbard whereas at mooring on Oct 4th the ship was 1646 km away on Oct 4th. If this rate keeps up (it won't), it would take 579 days drifting on a WGS geodesic (won't happen) to reach Longyearbyen (won't happen in 2020-22).

I've attached the updated archive of S1AB images of the Mosaic floe. In addition to timestamp, rough and precise lat,lon, wind speed, wind direction and ship temperature each entry has direct links to both GFS nullschool and the jp2 image at The former is built out of the preceding variables; the only technical tricks involve nullschool using lon, lat order and rounding odd times down (eg 02:59 to 00:00) which is easily fixed with modular round-off relative to the 3-hour spacings (eg 01:31 to 03:00). That's MROUND(RIGHT(timestamp,4),300) in your spreadsheet.

It's quite feasible to add thumbnails of the Mosaic floe, P-buoy tracks and regional wind the Polarstern is experiencing to each timestamp row in the S1AB database without growing file size too badly. A better alternative might be to make a mp4 at various scales out of every 3-hour nullschool GFS since mooring and flash those that have associated imagery.
Title: Re: MOSAiC news
Post by: uniquorn on December 08, 2019, 09:41:04 PM
This ani runs at approximately the speed that it was written. Lat/Lon and distance to 4dp for enthusiasts to check. No coloured lines. Fortunately it's not equilateral so it should be obvious, for now, which distance is which.

Tech note: I think there is still an issue with the animation timing. Some of the distances are very accurate, others are just close. The distance calcs are done separately (finally found mapply) before the ani so I think some frames show distance from an adjoining line of data. Could go back to Octave where there is full control of the ani (but no projection as yet) or investigate other R ani options. Reducing accuracy to 2dp would probably cover it though

hav.dist <- function(long1, lat1, long2, lat2) {
  R <- 6371
  diff.long <- (deg2rad(long2) - deg2rad(long1)) <- (deg2rad(lat2) - deg2rad(lat1))
  a <- sin(^2 + cos(deg2rad(lat1)) * cos(deg2rad(lat2)) * sin(diff.long/2)^2
  c <- 2 * asin(min(1, sqrt(a)))
  d = R * c
Title: Re: MOSAiC news
Post by: psymmo7 on December 08, 2019, 10:38:13 PM
* blumenkraft is handing over the baton to Psymmo
baton received - waiting for audio log book entry Nr. 9
Title: Re: MOSAiC news
Post by: blumenkraft on December 09, 2019, 06:18:08 PM
@Psymmo 👍🏽

RAMMB-SLIDER not updating. :(

(Meaning i can't confirm Uniquorn's GIFs ATM so better take them with a grain of salt. </kidding>)
Title: Re: MOSAiC news
Post by: uniquorn on December 09, 2019, 08:44:15 PM
drift update. Thanks for the translations.
Title: Re: MOSAiC news
Post by: blumenkraft on December 09, 2019, 08:47:52 PM
Welcome, Uniquorn. My pleasure. :)
Title: Re: MOSAiC news
Post by: Jim Hunt on December 09, 2019, 09:02:52 PM
The Kapitan Dranitsyn..... last reported on Dec-03 at 11:30 UTC.

CruiseMapper reveals the current position of Kapitan Dranitsyn and numerous other icebreakers:

No history seems to be available however.
Title: Re: MOSAiC news
Post by: uniquorn on December 09, 2019, 09:45:32 PM
Thanks Jim, 84.26N108.9, that would put it about here.
edit: widened the area in case it is fast moving.

Title: Re: MOSAiC news
Post by: A-Team on December 09, 2019, 11:04:09 PM

Nice! Note that the GPS is to five decimals, unlike the one that Mosaic shares. Still no history at Sailwx after Dec 3rd. Cruise Mapper only works in certain browsers (such as Mac Chrome but not Mac Opera). Mousing around on the lat,lon bar does move the ship around but the time associated with that move is not shown. What time there is, is "local time" in the middle of nowhere, not utc! That might be either Murmansk or Tromsø.

On a cruise ship, meal times are in local time. The Polarstern also does not keep utc but instead it has been walking it back so as to synch mealtimes when the KD arrives.

This is great that the two ships are already on the same tile at Polarview. I don't see a bright dot yet for the KD but it should be down there. The captain has 35 years of icebreaker experience so is no doubt taking the easiest route.

GFS shows good weather for the rendezvous, the first real break Mosaic has had. No way could they transfer all that diesel with km wide leads opening and closing. The Polarstern is moving north somewhat left of the wind which may be attributable the deflection by the massive ice pack and fixed CAA islands ahead.
Title: Re: MOSAiC news
Post by: uniquorn on December 10, 2019, 10:45:31 AM
A bit easier to spot KD today.
Title: Re: MOSAiC news
Post by: A-Team on December 10, 2019, 11:50:39 AM
Nice spotting. It is on all three Polarstern S1AB today, including the PolarView plug in with its precision lat lon mouse-over.

Rendezvous weather five days out remains bland. The Polarstern will be more or less in the same position it is now. The personnel there now will have ample time to have equipment deployed on the ice brought back into working order before turnover (to the extent that's possible).,90.00,1100/loc=120.9,86.5
Title: Re: MOSAiC news
Post by: JayW on December 10, 2019, 11:54:36 AM
RAMMB-SLIDER not updating. :(

Updating again, you can see the icebreaker KD approaching in this shot.
Click to run.
Title: Re: MOSAiC news
Post by: A-Team on December 10, 2019, 12:58:55 PM
The white dot seems to be in the wrong location(?). The KD is not preceding due north as shown but rather mostly east on the other side of 120º.
Title: Re: MOSAiC news
Post by: JayW on December 10, 2019, 01:43:33 PM
Oops, should've specified.  I was looking at this dot on the left. I assumed the one moving due north was the PS.  I was trying to get both in the view

Title: Re: MOSAiC news
Post by: A-Team on December 10, 2019, 04:08:13 PM
Thx, Jayw! It seems like the second latitudinal circle is not 86º as I thought but maybe 87.5º? (Best to have two  of each labelled for scale.) Indeed the PS has had a strong tailwind from the south.

Is there any meaning to the tumbling of the Polarstern image, or just variable cloud cover obscuring part of the heat source? (The Kapitan Dranitsyn steps are quite big as it is under steam.)

The bottom Lagranian/Eulerian double animation of the 4 S1AB today does not indicate major changes in the ship's orientation that could explain tumbling though the Mosaic floe seems to change quite a bit despite steady conditions.

It can very much be affected by 'action at a distance' elsewhere in the ice pack. That is, the area including the Mosaic floe is seen moving due north for several days but there is already thick ice between it and the CAA -- where does it go?

The 06:45 S1B came in ... it seems to show rapidly disappearing tracks relative to the three S1AB composite back in post #396. How much of the non-linearity is due to the KD following a favorable path through the ice and how much is due to ice shifting and shearing over five hours?

2019 12 10 0635
2019 12 10 0408
2019 12 10 0319
2019 12 10 0140
Title: Re: MOSAiC news
Post by: blumenkraft on December 10, 2019, 04:13:12 PM
And again, RAMMB-SLIDER is stuck at 07:02GMT ... ARGL!

KD here >>
Title: Re: MOSAiC news
Post by: blumenkraft on December 10, 2019, 05:21:26 PM
Is there any meaning to the tumbling of the Polarstern image, or just variable cloud cover obscuring part of the heat source?

JPSS/SNPP is by default a little wobbly. There seems to be an alignment issue.

Atmospheric turbulences could be another reason.
Title: Re: MOSAiC news
Post by: A-Team on December 11, 2019, 09:58:32 AM
The Kapitan Dranitsyn is making surprisingly good time and on the S1B  04:00 this morning was only 112 km due south of the Polarstern. On the S1B 0538, the frozen-in Polarstern had passively drifted a slight distance north and west whereas the KD was actively underway as well benefitting from the same drift.

Since we have two lat,lon for the two ships from two satellite images 1.633 hours apart, it can be  calculated (haversine) that the KD has closed in on the PS 10.6 km in that time which suggests it is preceding rapidly in thin ice and would rendezvous in 15.6 hrs except that thicker ice will slow it down but still 24 hrs seems reasonable.

GFS nullschool has a different updated forecast, showing the Polarstern on the edge of an anti-cyclone centered in the Chukchi for the next few days. If so, winds will pick up somewhat and drift will less towards the pole and more (unwanted) drift east (yellow arrow). This represents less than ideal but still manageable conditions for docking and fuel, equipment and personnel transfer.

The KD will likely dock alongside but outside of the Polarstern which is moored with the starboard side along the Mosaic floe. The involves circling around from the east so as not to create a trail of fractured ice that would later affect leads and pressure ridges in the experimental area.
Title: Re: MOSAiC news
Post by: uniquorn on December 11, 2019, 01:40:44 PM
thicker ice will slow it down
Based on the ice mass balance buoys in the area it doesn't look like the ice will present much of a challenge. It's of some concern that the ~1m ice at 386850 doesn't appear to have thickened much at all.

drift update, a new northerly record? see below
edit: forum still displaying 700px gifs at 580px
Title: Re: MOSAiC news
Post by: blumenkraft on December 11, 2019, 05:45:21 PM
Day&Night band overlayed with M15 band.

The KD captain seems to follow the leads.
Title: Re: MOSAiC news
Post by: blumenkraft on December 11, 2019, 06:52:44 PM
Hmm, not much way was done towards PS between 09:17 and 14:21 UTC.  ???
Title: Re: MOSAiC news
Post by: A-Team on December 11, 2019, 07:03:45 PM
drift update, a new northerly record?
Yes. Just paste the whole raw non-tabbed page into a database and sort descending, the northern most latitude will pop to the top since it is on the far left. However from five day GFS, drift will be mostly back east and south.

86.6  120.5 19-12-11 16:00    7  170    -26.1

For the 128 S1AB times to date, the winds, heading and temperature statistics to date:

ave   7.8  137  -18.6  85.7474   122.9168
max   17   360  -3.9   86.4748   135.8584
min   2     10  -30.9  84.7617   113.0207

Hopefully we can get all caught up in our tracking endeavors at the time of transition from leg 1 to leg 2. The Kapitan Dranitsyn may be bringing a whole new batch of them.

We need a dedicated buoy adopter like in days of old. It was easier with 1-2 buoys, now it is a swarm. No more expesnive Mosaics after this; from here on out it will be more, sturdier, smarter buoys. By the tens of thousands if needed.

The overall situation with buoy monitoring is complicated. Meereis Portal does not keep up at all; IABP is more comprehensive but has strange reporting practices -- buoys appear and disappear over time whereas once a buoy is deployed and working it should only drop onto the non-reporting list of dead buoys, never be deleted.

Below the old Oct 31 buoy collection is reconciled with a new Dec 11 download. Of the 96 buoys currently listed, 15 are dead (have not reported in over a week). A disproportionate number of these were set out by AWI:

300234062881930   SVP-B   AWI   11 10 19   84.98   134.5
300234066081180   Snow    AWI   17 10 19   84.62   133.29
300234068519770   CTD     AWI   25 10 19   85.32   128.36
300234068713430   CTD     AWI   26 10 19   85.55   126.17
300234066346540   Snow    AWI   02 11 19   85.96   122.71
300234068160720   CTD     AWI   22 11 19   85.19   125.38
300234066080170   Snow    AWI   26 11 19   86.04   117.67
300234066344810   Snow    AWI   28 11 19   86.00   119.17
300234066415350   UT      OSU   26 09 19   81.57   107.51
300234066412350   UT      OSU   12 11 19   86.04   117.56
300234068210190   SVP     PRI   02 12 19   85.92   113.85
300234065982560   GPS     TUT   28 10 19   85.62   126.86
300234065988570   GPS     TUT   04 11 19   85.99   116.25
300234065980580   GPS     TUT   31 10 60   85.41   129.51
000000000900111   ITP     WHO   27 11 19   86.07   116.68

300234066412350   dead list, on new, missing old
300234066415350   dead list, on new, missing old

000000000900111   dead list, on old, on new
300234062881930   dead list, on old, on new
300234065980580   dead list, on old, on new
300234065982560   dead list, on old, on new
300234065988570   dead list, on old, on new
300234066080170   dead list, on old, on new
300234066081180   dead list, on old, on new
300234066344810   dead list, on old, on new
300234066346540   dead list, on old, on new
300234068160720   dead list, on old, on new
300234068210190   dead list, on old, on new
300234068519770   dead list, on old, on new
300234068713430   dead list, on old, on new

300025060314090   on new, missing old
300234060320930   on new, missing old
300234060320940   on new, missing old
300234065091110   on new, missing old
300234065094850   on new, missing old
300234067705700   on new, missing old
300234067705760   on new, missing old
300234067706680   on new, missing old
300234067707750   on new, missing old
300234068706290   on new, missing old
300234068706330   on new, missing old
300434063382860   on new, missing old
300434063384820   on new, missing old
300434063386850   on new, missing old
300434063387850   on new, missing old

300234066080220   on old, missing new
300234066081220   on old, missing new
300234066082230   on old, missing new
300234066084230   on old, missing new
300234066085220   on old, missing new
300234066087220   on old, missing new
300234066089220   on old, missing new

000000000090094   on both, still reporting
000000000900102   on both, still reporting
Title: Re: MOSAiC news
Post by: A-Team on December 12, 2019, 10:51:46 AM
The Kapitan Dranitsyn was not where I had expected it to be this morning but rather well east of the 120º meridian where the Polarstern sits becalmed at 86.6º. Still the KD track is almost to 86.0º so it has some 65 km to go. Location data from cruise mapper do not agree with the Sentinel track. The course of the KD stands out best on the 05:30 S1A:

The KD may have other assignments such as retrieving moorings or placing/servicing buoys and other instruments. Its mission was initially said to be 5-6 weeks, quite a bit more time than needed just for a refueling and crew swap.

Mild GFS weather the next five days will facilitate the KD's refueling task. No significant drift will be taking place through Dec 15th. The current ice thickness averaged over ~25x25 km is 1.41 m according to cryo2smos observational product. Specific micro sites will vary.

To avoid damaging the research camp during the resupply missions Kapitan Dranitsyn will drop anchor several hundred meters away and pump fuel to Polarstern using heavy-duty hoses. The remaining supplies and the researchers’ equipment will be hauled to camp on sledges pulled by snowcats. On her return journey, Kapitan Dranitsyn will take any waste that isn’t suitable for Polarstern’s special litter-incineration system... Fuel depots for long-range helicopters have been set up on Bolshevik Island but are not expected to be used... Mid-June 2020, the Swedish research icebreaker Oden handles exchanges .... The new Chinese icebreaker Xue Long 2 is assigned mid-August resupply.
Title: Re: MOSAiC news
Post by: uniquorn on December 12, 2019, 03:05:54 PM
drift update, ~12 days in 50 frames
Title: Re: MOSAiC news
Post by: A-Team on December 12, 2019, 07:16:55 PM
Fabulous! The hairpin turn coincides with what we know from Sentinel imagery to be the most disruptive event of the trip. So far, it has gone unreported from the Mosaic camp; with all eyes now on the KD refueling, trip home, and a lull in the weather allowing repairs, it will probably never get reported other than in distant memoirs.

Continuity in data collection is quite important for some but not all instruments. The issue is not a few missing hours but rather permanent loss of experimental equipment and abandonment of deployment sites. Mosaic costs some $280,000 a day so loss of a million-dollar sensor is just a rounding error; the problem comes with the logistics of replacing it (or not).

The animation below cuts to 34 critical hours centered on the hairpin and adds available S1AB imagery, hourly weather data from sailwx-assisted awiMet (which is quite gappy as usual), plus revisited (but not reanalyzed) GFS wind motion links keyed to the hourly and PolarViewer links keyed to the S1AB.

The questions here: what caused the severe motion in and around the ice camp, to what extent were they local, regional or whole ice pack in scope, and could they have been anticipated from the GFS forecast?
Title: Re: MOSAiC news
Post by: uniquorn on December 12, 2019, 09:12:15 PM
<Catch up on buoys>
63 iabp buoys visible on this image, 86 are loaded so some are reporting late or not at all. An animation should show that up. Those in colour are reporting temperature at surface.
Title: Re: MOSAiC news
Post by: uniquorn on December 12, 2019, 09:58:16 PM
Closer to PS
p201 is 8912800
p207 is 8918790
nearest buoy to PS on this selection is probably 8215980
Title: Re: MOSAiC news
Post by: blumenkraft on December 13, 2019, 09:07:23 AM
The KD arrived as of 3:33 UTC !!

Will post aRAMMB-SLIDER GIF later today.
Title: Re: MOSAiC news
Post by: A-Team on December 13, 2019, 11:49:02 AM
Round-about route the last day as the going got toughter but docking as expected to the east of the Polarstern on the 05:31 on Dec 13th. The Kapitan Dranitsyn is still moving into position between 03:43 and 05:21. The 07:00 S1B just misses in its coverage.

The tracks have to be captured within 24 hrs on a S1AB or they become all but impossible to follow.

The large extended black lead to the south (up) is an unexpected overnight development but so far seems to have no effect on fueling or Mosaic ice camp equipment. It is not notably active between 03:43 and 07:00. There is no sign of it yesterday on the 05:30 S1A.

Regionally, there is quite a bit of ice dynamics, mostly shearing. The PS and KD are perhaps 10 km north (down) of a massive block shear zone. The overnight pair of images below are being viewed in a coordinate system in which the Polarstern is fixed.

This would have been a full-on disaster had the shear line come through Ice Camp while the Polarstern was refueling or exchanging out equipment and scientists. It didn't and people on the ground may have been oblivious to it.

The explanation of the event is the passing of mild wind shear from southeast to northwest across the Polarstern's position. At no time were winds extreme; instead the delta of wind (6 km/hr to 31 km/hr) caused the ice to move differentially across the gradient.

The ice is still too mechanically weak this winter to distort south of the PS's position so brittle-fractured along a line parallel to wind stress where it is thicker. The event is largely over per GFS though ice movement is foreseen to somewhat reverse in coming days. Again, this was not a winter cyclone, just uneven regional wind stress.

On uniq's upcoming (we hope!) mega buoy animation, we can expect some sharp zigzags distinguishing buoy sets above and below the event. This will greatly improve time resolution of the main fracture over what 24-hr S1AB can do, in this instance 24 less 2:36 hrs compared to half-hourly or even ten minutes.

2019 12 13 0343
2019 12 12 0619

Start at the location below and step back in 3-hr steps (keyboard 'j').,90.00,1100/loc=119.5,86.6
Title: Re: MOSAiC news
Post by: Aleph_Null on December 13, 2019, 06:59:45 PM
I'll only do this once, because I have nothing to add but gratitude. A-Team's last 24-hr shear gif is jaw-dropping. It sure looks to be a dangerous place. The people on that boat are clearly risking their lives for invaluable understanding of the icecap. Above and beyond... what can you say?

The reporting in this thread has been riveting, and also invaluable for understanding the icecap.
Title: Re: MOSAiC news
Post by: uniquorn on December 13, 2019, 09:42:09 PM
Festive season so a little bit late. Here testing animation of many iabp buoys, one showing a spurious latlon and a couple who think it's14dec already. It may take more analysis (than I am capable of right now) to detect that shear.
Interesting that one buoy to the south jumped backwards though

see update below.
Title: Re: MOSAiC news
Post by: A-Team on December 13, 2019, 10:04:11 PM
24-hr shear gif is jaw-dropping
Early morning, just absent-mindedly updating the S1AB collection, not seeing any drama on the ingest of the three Dec 13's, not expecting much by way of drift at low wind, at best thinking about the KD cutting a swath pre-conditioning the ice camp to future lead and ridge problems, then wondering when that meaningless lead came about, checking with the 24 hr, making the overlay pair, running it real fast in ImageJ, then my jaw-dropping moment seeing the long shear boundary, to pondering what an event-driven diesel spill during refueling the PS would mean for Arctic research, to asking whether risk to researchers is maybe higher than anticipated (indeed higher than acceptable, this being the 4th major incident in 69 days), to looking at historical stats on expected major cyclones of winter still ahead.

We have the tools to do a lot more analysis on the Friday The 13th fracture (FT13). It does seem fairly easy to recognize conditions conducive to disruptive events a couple days out on GFS, though it seems we don't know enough about ice pack strength to differentiate between deformation and shear, much less predict location of shear lines relative to the Mosaic ice camp. The surprise is, we do know enough to make those predictions.

The attachments below are just two plain text documents giving active urls to all Sentinel Viewer back to mooring and their accompanying PS position- and S1AB-aware GFS nullschools. The buoy position repositories and ship weather are at their respective archives

Sure, we could post a swinging risk needle like the Forest Service does for fire hazard but would it really be actionable down at the ship, would someone not go out to tend a deployed instrument when the needle was on yellow or red?

The buoy swarm animation provides a very sensitive nrt tool that can detect and report occurrences of not-too-remote rifting, though their current distribution was not thought out and is sub-optimal. However an after-the-fact announcement is not a warning, unless the shearing is taking place in abrupt stages (like earthquake after-shocks).

Here Uniq will be looking for an upper zone of plastic buoy position deformation in conjunction with a lower zone of rigidity that preceded the rupture at the interface. Would that give hours of warning or minutes? Would that give warnings of all events or just some?

Here we need a whole lot less mickey mouse from the inhabitants of the Mosaic buoy deploying academic silos, like delays in posting, lack of Iridium redials, lack of time synchronization, irregular GPS reads, lack of gap repair, lack of QA, and worst of all, dumbing down the decimal points (AWI, I'm talking to you).

In other words, changing inter-buoy distances provide an interferometric mesh from which a tensiometer is built. GPS is not up to lasers but still very capable today since Every Decimal Point Matters even if the last is not quite as good as the first. Right now, buoy runs take too long for the desktop but there are ultra-fast migration options for anything in R.

Given eight years of planning, why are we scrambling today to put together risk mitigation software?
Title: Re: MOSAiC news
Post by: uniquorn on December 14, 2019, 03:51:31 PM
Update of yesterday's test animation of many iabp buoys, one showing a spurious latlon and a couple who think it's15dec already. Will make a manual correction of their DOY at some point.
Title: Re: MOSAiC news
Post by: Tor Bejnar on December 14, 2019, 06:24:24 PM
one showing a spurious latlon
Maybe it had to go to the loo, but came right back  ::) :D
Title: Re: MOSAiC news
Post by: A-Team on December 14, 2019, 08:46:17 PM
one showing a spurious lat lon and a couple who think it's 15 dec already. Will make a manual correction at some point.
Somebody not doing a proper job of curation and posting in ingestible format at the upper end makes pipeline science all but impossible for everyone downstream. Buoys and AWI wx present new problems every day. (Despite that, the latter is ingested directly by ECMWF for Arctic forecasting.)

Even if you made manual corrections all the way back to Oct 4th (and posted them prominently), there is no mechanism to correct the source (ie fix shabby or non-existent QA tools there). Tomorrow, instead of rolling your animation forward on auto-pilot to the next day, the add-ons will have to be manually corrected. For 95 buoys? For 95 pipelines feeding large scale climate prediction?

Following up on the near-catastrophic shear on Dec 13, the buoy system should show a lurch to the right (west) on the more southerly buoys above the shear line relative to the buoys on the Polarstern side of the line (north is below).

However that is not immediately apparent, probably because we need to run the buoy data much closer to its intrinsic positional resolution. That is, it would suffice to limit the graticule to 86.50-86.65 and 117-121 or about a tenth of the area in uniq's animation above. This would allow more of the 4-5 decimal points in the buoys's GPS to come into play, not just one.

Alternatively, if the rupture was not abrupt but spread out over a few hours, we might have to dig into select buoy db numerical analysis rather than rely on graphics to date the event.

In terms of weather contribution to causality, 3-hour GFS shows a complete reversal of wind direction accompanied by an up down up cycle of wind strength with sharp wind curvature in between though not right at the Polarstern's location. Note this wx depiction would not be identical to the GFS forecast on Dec 12th because it re-initializes each day; the time series was made well after the fact.

Until the buoy reanalysis is finalized, it is not feasible to assign a time of shear rupture to a pair of bracketing GFS frames; even then we don't know the offset between cause and effect.
Title: Re: MOSAiC news
Post by: uniquorn on December 14, 2019, 10:27:06 PM
closer to the shear, dec11-13 in 200 frames for detail, removed the 4smb's with faulty DOY, kept the incontinent one, no grat labels. May have time tomorrow to compare a couple each from below and above.
Title: Re: MOSAiC news
Post by: uniquorn on December 15, 2019, 04:28:39 PM
Quick messy comparison of 4 buoys close to the shear. The drift path difference would appear to be subtle at this resolution. The datetime and buoyid's are good. LatLon text is not updating yet.

#420 digitized shear...
p201 is 8912800
p207 is 8918790
PS should be located between these two buoys, one square to the left. Perhaps my manual labelling is suspect?

< the buoy system should show a lurch to the right>
 lurch may happen before the animation starts, though the timing is wrong. Will zoom in further I think.
Title: Re: MOSAiC news
Post by: uniquorn on December 15, 2019, 04:57:19 PM
I'll only do this once, because I have nothing to add but gratitude.
An occasional 'pressure, wind & density' focussed on the mosaic area might be useful. Particularly for this recent event.
Title: Re: MOSAiC news
Post by: blumenkraft on December 15, 2019, 05:17:02 PM
Title: Re: MOSAiC news
Post by: A-Team on December 15, 2019, 05:52:40 PM
Right, this is all about getting to the right scale as constrained by forum image widths. Previously we've determined that a degree of latitude as marked on S1AB jpg with lines is 2712.26 pixels for what we know is 111.111 km on WGS84 (which we have to use here as all GPS data refers to the earth ellipsoid).

Thus image distances can be measured in pixels (often fractional if points are diagonal) and converted to meters by multiplying by 41.0 for both S1AB jpg and S1AB.8bit.jp2 (at 100% zoom in the polar viewer plugin).

Doing this, it emerges that the Polarstern was 3703 m north of the shear line. The 79 km long open lead created in this area ranged from 730 m in width to a more typical 487 m to 159 m at narrows. A lead of this width cannot be bridged by wooden palettes and a sled, nor is it feasible to kayak across regularly carrying staff, bear guards and fuel for instruments (as Mosaic was doing earlier).

The dramatic regional shear animation of post #412 that compared Dec 12 06:19 to Dec 13 03:43, repeated below, was done in Polarstern-stationary coordinates (lagrangian) which removes background ice pack movement (secular drift).

The rifting took place as the pack as a whole moved almost due westward by 4301 m but with a 410 m north component. Relative to the Polarstern, the shear area moved an additional 4146 m southeastward.


It's worth walking through GPS decimal points which have quite different associated measures for lon than lat.

At 86.6º, a tenth of a latitude degree increment represents 11.111 km, a hundredth 1111 m, a thousandth 111 m, a ten-thousandth 11.1 m and a hundred-thousandth 1.1 m.  The first is what we are looking at with sailwx and AWImet; the second what GFS-nullschool can discriminate at maximal scale, the third enough to show a buoy lurch and the last the nominal resolution claimed by typical Mosaic buoys (4th GPS decimal point).

Note the buoys are in motion during whatever time it takes for them to measure their position. Those speeds, given as the color scale on uniq's animations rarely exceed 1 km/hr which is 1000 m per 3600 seconds or 0.27 m/s. So if it took them 5 seconds, that would be 1.4 m which might amount to a correction to their last decimal.

2019 12 13 0343  86.6  119.5  86.5918  119.4764  rough and refined PS locations post shear
2019 12 12 0619  86.6  120.1  86.5982  120.1285  rough and refined PS locations pre shear

So what needs to be done -- and I am leaving this to Tor B -- is download the data files for 2-3 buoys above the shear and 2-3 below using the map below (or as provided by uniq), delete the irrelevant columns, combine into a single spreadsheet with times of reported synchronized by row. Then add a new column and fill with the subtraction of above/below longitude columns.

The graph should show a big lurch at the hour of rifting.

As a control, go back a week or so to establish the big lurch is way out of the ordinary, not 'normal variation'. Going forward, the winds have hardly been enough to stress the ice, meaning delaunay buoy triangulations across the shear line will have stable edges.

Nonetheless, this morning's pair of S1AB 3 hrs 16 min apart don't show a quiescent situation on the Mosaic ice pack (lower animation). Indeed a small rift seems to be closing at the later time. This does not necessarily affected deployed instruments as only a small flat area near the ship is currently used.

The Kapitan Dranitsyn can be seen crossing the shear line within hours of its formation. It's not clear what would happen to an icebreaker caught in a sudden shear event. The Polarstern, being frozen in for a year, is more at risk.

Shear events with km scale displacements are multi-daily events even at the scale of a single S1AB frame, but one crossing a 118 m object amidship would not be expected unless the ship, like Los Angeles, is sitting on an inactive fault line predisposed to re-awakening.

While the Polarstern has not disclosed the data that would allow analysis (it being below the resolution of S1AB), they have had slabs of ice sliding back and forth in front of the bow, micro-shear events. In addition, the undocumented Dec 6th event saw a larger faulting event come right through Mosaic ice camp.

In summary, the ice has been shifting around a lot already this winter at various scales with only 2 months down and 4-5 months to go. It's tempting to say 'more than usual' but hard to go beyond anecdotal impressions. This has been a very odd winter in terms of no coherent ice pack drift (as visualized above in Ascat whole-Arctic mp4).
Title: Re: MOSAiC news
Post by: uniquorn on December 15, 2019, 09:01:05 PM
Quite festive here today but also some interest in arctic buoys so here are 7 buoys close to the rift. We've voted that the one on it's own has a data glitch (8916790).

edit: I change my vote since it looks like 8916790 was right on the rift.
Title: Re: MOSAiC news
Post by: gerontocrat on December 15, 2019, 09:11:20 PM
In my naivety I thought the MOSAIC project might be lucky as far as the solidity of the ice pack was concerned.

For why? The Central Arctic Sea froze up so early this year from a minimum that was also higher than in recent years.

How wrong can I get?
Title: Re: MOSAiC news
Post by: A-Team on December 15, 2019, 09:11:52 PM
Here are recent paper titles from the highly qualified Mosaic leg 2 leader, AWI's Christian Haas. His interests are much more remote sensing and ice-related than leg 1 atmospheric physicists. Let's hope that there will be a much more open science focus to Polarstern communications in coming months.

Winter rain, as Haas notes, would really be a game-changer for snow thermal properties and spring albedo. The recent polar lightning, detected by a Finnish company specializing in remote detection and employing my neighbor, also came as quite a surprise. The Polarstern is not set up to detect it unless it is right overhead. Rain? The PS may have doppler radar but not one dedicated to rare events.

Some strong winds are expected this week but nothing approaching gale force. The GFS outlook has changed so much from yesterday that it is hard to predict coming Polarstern drift, though it will be almost entirely to the west (smaller longitudes) with a small component north, so maybe 86.7, 114.0 by Dec 20th from where it is now, 86.6, 117.7.

-- Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter

-- Ice and snow thickness variability and change in the high Arctic Ocean observed by in situ measurements

-- Helicopter-borne measurements of sea ice thickness, using a small and lightweight, digital EM system

-- Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter

-- 13-years of sea ice draft observations in the Laptev Sea from moored ADCPS and ULSs

-- The timing and intensity of snowmelt processes on sea ice are key drivers

-- Seasonal changes in snow properties from passive and active microwave satellite observations: 

-- Vertical snow structures from in-situ and remote sensing measurements

-- The Arctic Permafrost Geospatial Center-a portal for high-quality open access scientific data related to permafrost

-- Snow depth on Arctic sea ice derived from airborne radar measurements

-- Large-scale ice thickness distribution of first-year sea ice in spring and summer north of Svalbard

-- Contrasting ice algae and snow dependent irradiance relationships between first year and multiyear sea ice

-- Snow-related variability of spectral light transmittance of Arctic First-Year-Ice in the Lincoln Sea

-- Seasonal changes in snow properties from passive and active microwave satellite observations

-- Snow depth on Arctic sea ice derived from airborne radar measurements

-- 13-years of sea ice draft observations in the Laptev Sea from moored ADCPS and ULSs

-- Contrasting ice algae and snow dependent irradiance relationships between landfast firstyear and multi year sea ice

-- The 2018 North Greenland polynya observed by a newly merged optical and passive microwave sea-ice concentration

-- Snow-related variability of spectral light transmittance of Arctic First-Year-Ice in the Lincoln Sea

-- Contrasting ice algae and snow dependent irradiance relationships between landf-ast first year and multi-year sea ice

-- Ice and snow thickness variability and change in the high Arctic Ocean observed by in situ measurements
Title: Re: MOSAiC news
Post by: blumenkraft on December 16, 2019, 06:37:01 PM
Press release from AWI: Change of Shifts at the North Pole

Link >>
Title: Re: MOSAiC news
Post by: uniquorn on December 16, 2019, 07:09:39 PM
drift update. Latitude lines at 0.25. The iabp raw data is a bit messy so will probably go back to the meereis buoys tomorrow.
Drift speed picking up again.
Title: Re: MOSAiC news
Post by: Tor Bejnar on December 16, 2019, 08:25:26 PM
from B_'s link (above - Change of Shifts at the North Pole (
Leg 1 of the MOSAiC expedition in numbers:

To date, the Polarstern has drifted 200 kilometres toward the North Pole. Thanks to its zigzagging course, the total distance travelled is 720 kilometres.

The highest drift speed – 1.4 km/h – was reached on 16 November 2019. On this single day, the ship drifted more than 20 kilometres.

Some of the research stations on the ice were moved up to 600 metres by processes in the ice.

There have been 8 days with gale-force wind speeds exceeding 15 metres/second (54 km/h). During the most powerful storm, on 16 November 2019, wind speeds of up to 100 km/hr were clocked.

There have been polar bear sightings on 9 days, including sightings of lone bears, and of mother bears with one or two cubs each.

As a result of these sightings, or approaching storms, the ice floe has been evacuated at short notice roughly half a dozen times. And there were other days on which the presence of bears or storm conditions made it impossible to go out on the ice at all. / made the ice off limits.

To date, MOSAiC participants have spent roughly 500 hours working on the ice.

Temperatures bottomed out at minus 32 degrees Celsius; the ocean temperature is currently minus 1.5 degrees Celsius at the surface.

More than 5 kilometres of roads were created on the ice’s surface.

The research camp on the ice floe consists of ca. 100 tonnes of equipment.

Ca. 20 terabytes of data have been gathered.

The researchers and crew have consumed 12.7 tonnes of food.

125 buoys, which serve as autonomous monitoring systems and can transmit their data directly by satellite, have been deployed.
Title: Re: MOSAiC news
Post by: blumenkraft on December 16, 2019, 08:26:12 PM
Ships are awfully close together, no?
Title: Re: MOSAiC news
Post by: Tor Bejnar on December 16, 2019, 08:39:30 PM
They had to be close to move some supplies by crane.
(If they'd used baby-delivering cranes (, they could have been farther apart.)
Title: Re: MOSAiC news
Post by: A-Team on December 17, 2019, 12:24:03 AM
Oh what tangled webs we weave, when first we practice to deceive (W Scott, 1808)
Here the wind power density during leg 1 is shown once a day for days that have have S1AB images, with a few gaps filled in by interpolation so all 78 days are represented. The four storm events show up fairly clearly on the slides though here the GFS needs to have its 3-hour resolution shown that brackets each event.

These unfortunately run into file size problems at decent resolution, even compressed as mp4 (which works better at faster displays than for slide shows; nullschool images have very complex color and compress poorly). I don't really see a way forward for a year long expedition other than breaking into months or legs.
Title: Re: MOSAiC news
Post by: A-Team on December 17, 2019, 10:53:27 AM
The video shows how the initial grid distorts over time by the uneven ice drift over time within the grid array. This results in opening (ice divergence) and closing (ice compression and ridging), shear and vorticity. This shear caused a massive crack to form through the experiment ice floe, disrupting the experiments and forcing movement of some of the instrumentation.
Grid distortion is another approach to visualizing ice pack motion around the Polarstern from R Kwok at JPL that was posted as a poor quality youTube by ESA (with a gratuitous rocket launch appended). For better quality, see the original large slow file  (5.2 MB, 720x 720):

No information provided about how it was made or what it shows quantitatively; it uses 23 of the 41 available S1AB of Oct 2019. Usually AI is used to match up features in consecutive image pairs (which can be done in ImageJ) and the distortion gridded after interpolation. Only rarely can features be followed for any length of time so the rolling pair uses different ones.

The scale is reduced so the white dot of the Polarstern is hard to see. It is held fixed but proper alignment requires rotation before translation as the ship wandered quite a bit over the month, with longitudinal extremes of 124.5 to 135.8.

Here we made use of high-resolution radar images from the German TerraSAR-X satellite to help locate the best-possible floe. Copernicus Sentinel-1 satellites help follow and predict the ever-changing drift of the sea ice up to 300 km away from the ship.

The Japanese ALOS-2 satellite with its PalSAR-2 sensor uses a much longer wavelength than both Copernicus Sentinel-1 and TerraSAR-X to map sea-ice floes and conditions below.  ALOS-2 can provide on sea-ice conditions especially now that we are developing our own long-wavelength radar satellite called the L-band Synthetic Aperture mission ROSE-L which is one of the six Copernicus high-priority candidate missions. CIMR and CRISTAL upcoming sensors will also benefit, a microwave radiometer and ice/snow topographic altimeter.

Only one TerraSAR-X image has been released by Mosaic, mistakenly by a student; fortuitously it contained the floe selected a few days later. However the quality (as posted) was no improvement on Sentinel-1AB.

PalSAR-2 is much more interesting. I don't know if there is a public archive nor whether it routinely archives images the Arctic Ocean. The one posted example is intriguingly false color, suggesting either multiple wavelengths or HH+HV polarization color channels. It was taken on 19 Nov 19 but does not include the Polarstern in the scene (nor any location information).

L-band SAR has a longer wavelength relative to surface roughness compared with C-band SAR and has improved ice-type separability due to deeper ice penetration. However it does not do as well on melt-onset detection.

The DFD (German center for remote sensing) is providing TerraSAR-X images to the Polarstern in near-real time. Ground receiving stations in Inuvik and Longyearbyen help Neustrelitz rapidly process and relay the imagery to the ship. RADARSAT-2 imagery is also provided; in theory PolarView portals it but the imagery may only be relevant to the CAA.

In terms of fancy GPS onboard the Polarstern, the DLR (Deutsches Luft Raumfahrt ) installed a measurement system for receiving and storing raw signals from navigation satellites. They will be measuring the disturbances of the Galileo and GPS navigation signals with a high-rate receiver. Solar flare cause scintillations, fluctuations of the electron density in Earth's ionosphere which influence propagation of electromagnetic radiation; this degrades the positional accuracy derived from navigation satellites so counter-measures need to be developed.

The five-day GFS suggests a half day more of rapid westward loss in longitude (remembering that a degree of lon means very few km at very high lat) with lat gaining slightly to 86.7. The Polarstern will then spend a couple of days almost becalmed before heading back south and
east to locations it has been before.

A 70 day comparison is shown below. Although the Mosaic floe has changed rather dramatically over this time frame, some neighboring patches traveling with it remain identifiable. The later  image has been rotated to match the longitude of the first before translating the Polarstern dot to co-register.
Title: Re: MOSAiC news
Post by: uniquorn on December 17, 2019, 11:02:24 PM
Drift update, staying with iabp data but only using 3 buoys close to the ex-rift, south of PS. Distances and lat/lon are shown though the speed is a bit fast for checking (not that anyone ever did ;) )  ctr
Tech note: gif can be unoptimised using gimp
Title: Re: MOSAiC news
Post by: A-Team on December 18, 2019, 03:30:16 PM
Best yet!

Here is an ambitious alternative GIS offering from Meereis Portal that has some click-thru information on buoy names and properties. It does not seem to be working at at a sufficient number of lat lon decimal points to capture fine detail of tracks relative to the Polarstern.

Oddly it does not link to the Meereis buoy data launch itself or to their own hourly averaged weather data. Overall, it is slow to load and over-reacts to unintended mousing. Leaflet we've seen before in Mercator Ocean. A lot of these track-n-stack tools reinvent the wheel (aka Google Earth). full page version, 'share' button url captures location and zoom big overview

Meereis Portal is currently showing 102 'active' Mosaic buoys. The Polarstern (DBLK) itself is of course a giant buoy; when its lat lon is inserted, a sort shows the closest buoys. (However this won't be accurate unless all the times are in fact synchronized.)

Their master search tool shows 97 buoys, IABP lists only 96 Mosaic buoys of which 81 are still reporting and 15 are dead.

The :) from "communication specialists" at AWi says 124 buoys. Buoys must register an IMEI under international law, so the options are badly misinformed, ongoing crime, buoys installed on the main floe reporting directly over the LAN, and newly launched buoys brought by the KD not yet linking to IABP.

Winds are mild for now so only minor movements are seen in the ice pack near the Polarstern on 18 Dec 19. Since mooring, winds have averaged 7.5 m/s from 136º. The maximal sustained wind speed according to the ship's own anemometer was 21m/s on Nov 16th, again contrary to  :).

Here the issue is not what gusts of wind occurred on top of the 32m Met tower (or mast on the ship bridge  :) ) but how (unevenly) sustained wind power density coupled to the ice as stress (peak GFS, bottom image).

Temperatures have averaged -19.2º with a coldest sustained low of -30.9ºC, not  :). You would see conditions like this every winter in Chicago or Minneapolis but with 10x the snowfall.

2019P158   86.63   114.37
2019P201   86.61   114.35
2019P151   86.64   114.27
2019P124   87.06   114.25
2019P103   86.70   114.24
2019O4   86.77   114.21
2019P187   86.30   114.14
DBLK      86.67   114.1
2019P183   86.68   114.00
2019T66   86.67   113.96
2019P122   86.98   113.94
2019T62   86.67   113.94
2019P204   86.63   113.86
2019P153   85.92   113.85
2019P200   86.84   113.71
Title: Re: MOSAiC news
Post by: A-Team on December 19, 2019, 02:34:40 AM
Two blogs released today by co-leader M Shupe: these don't quite get up to cover the Dec 6th mega-event. With the complexity of the leg1/leg2 exchange and return to shore on the KD, that may fall through the cracks as the  :) AWI PR team :) for sure will never mention it (see #429 and #431 above).

24 Nov 19: "Today was especially challenging because there was fresh snow that had blown across everything, covering cracks and thin ice. Blowing snow in the air limited visibility, and gave a bite to the cheeks. On our way out there were new cracks right under the road, most passable on a snow machine if you keep moving.

Eventually the snow machine was no longer possible so we continued on foot, coming eventually to crossing that had been active before. It was hard to tell its conditions today, with all of the new snow. Some probing showed areas of strength and areas that were soft.

I probed on two sides of an area, finding strength, then took a step…. But my foot keep sinking down into the slushy ice-snow mixture. I quickly flattened out, my upper body and one foot on solid ice but my knee pushing down into the slush. Two travel partners were there to help, and I made it back safely onto fully solid ice.

I ended up with a wet knee and fore-leg, but no water inside my suit or boot. A bit of a thrill but safe in the end, and we made it through to do our work. On that same trip we had another wet boot, and there have been many similar occurrences, the most extreme being someone in up to their waist but quickly extracted.

30 Nov 16: Cleaned up after heavy polar bear damage to remote L2 site: a lot of problems with fingers and face masks in the cold and wind but got it transmitting again

03 Dec 19: Once again the ice dynamics have become active. High winds from the south have been pushing against our floe, and across the major shear zone that extended across the front of the ship.

We’ve seen a little bit of activity there in the last days, but not much. But now things have really come together, jagged pieces of ice getting pushed 3-4 meters up into the air, likely extending 20m below the surface.

Beautiful blue ice, with the winds whipping snow up and over the top in a swirling dance. This ridge was eating our power line, as well as two Nansen sleds that were parked by a little crack. These sleds were being used as a bridge to cross a 1.5m crack before. Now they were captive by the ridge, although mostly pushed up on top.

A small team of us went out to recover the sleds, successfully. The ridge groaned occasionally, but was most done with its movements for now. A new jumble of blocks, some the size of Volkswagens. And our power cable extending up and over the top.

We freed some of the tension on the ship side by helping to reroute the cable line. Then climbed up over the top of the ridge to the other side, to find that the cable had been dragged underneath a couple of huge blocks of ice. No way to move or break these.

The cable is still functional; Met City still has power. But we are out of cable connectors. So we can’t simply cut this line and then patch it back together with some new connectors. Our decision is to just leave it here for now, wrapped around these ice blocks and extending down into the water at one place."

Comment:  Should 3-4 high loose blocks of jumbled ice be treated as 3-4 m of ice thickness? What about keels 20 m deep created by one floe over-riding another?

No. These should not be conflated in thickness compilations with the millions of sq km of multi-year ice that is has built up from accretion of freezing seawater onto the under surface. Blocks of jumbled ice contribute nothing to extensional or compressional strength and melt very differently from MYI.

Pressure ridges do play a special role in sequestering wind-blown snow, decreasing its thickness and insulation of regular ice, making it more susceptible to spring melt pond formation (which these pressure ridges may contain and prevent drainage. Elevated rough-surfaced ridges could play a dominant role in catching the wind, thus in ice motion and further floe collisions in a runaway situtation of ridges leading to more ridges.

Keels have been studied extensively in the past by upward looking submarine sonar and today to a much more limited areal extent by underwater ROV. Keels initially impede ice dynamics as wind stress experiences drag. Over time, keels round out and erode, lessening drag and sea water advection.
Title: Re: MOSAiC news
Post by: A-Team on December 19, 2019, 12:16:28 PM
Google Earth Pro freeware and simple kml instructions provide an alternative to the Meereis GIS Portal and uniq's buoy tracking animations.

While GEP has a learning curve and the kml markup language an off-putting schema, it is easy to make a simple template to display a point, line or triangle, then stub in the lon lat numbers and related links from buoy or Polarstern tables.

The attached table for the Polarstern provides high resolution location data as well as the link to PolarViewer S1AB image and GFS nullschool weather. GEP allows each of these, as well as links to forum images (such as buoy animations) to be attached to each point of its display (second screenshot).

The kml format is just structured plain text that is human readable with a little practice. More importantly, anyone can download the data once the GE viewer is loaded. There is no sharing possible on the AWI setup. With an attached table, uniq could distribute the data underlying the buoy animations

While the view necessarily gets complicated if the PS and all 96 buoy tracks are loaded, it is easy to group these into sets and turn combinations on and off. The zoom has a phenomenal range so only the last few days can be displayed. Note the view is from space: plate carrée differs from plane polar coordinates though not so much at high zoom.

GEP will also calculate distances, perimeters and areas very accurately though this has to be done one at a time by request and manually captured. It is also feasible to port GEP to external web browsers that retain some of the main interactive features. That could then be linked in as a forum remote url.

Meanwhile, back on the ice, the Polarstern is basically becalmed but towards the middle of the GFS outlook will start drifting the wrong way again, south and east. Nonetheless, the S1AB imagery shows change on the Mosaic floe again today. Maybe with the staff turnover, someone there will finally provide active updates -- after all, improving satellite interpretation is one of the primary Mosaic objectives.
Title: Re: MOSAiC news
Post by: blumenkraft on December 19, 2019, 12:31:11 PM
According to satellite data, there was a ship leaving the vicinity yesterday (18th) around 13:00 UTC.
Title: Re: MOSAiC news
Post by: A-Team on December 19, 2019, 05:25:40 PM
Indeed the track of the Kapitan Dranitsyn can be see above leaving from the SE (middle left) the way it came in. We don't have enough resolution to see maneuvering in the immediate vicinity of the Mosaic floe.

The dotted box shows an ambiguous area where the KD may have had temporary difficulty finding an easy route. Otherwise, a straight track means the captain did not rate obstacles worth avoiding (ie no issues presented buy thick ice or pressure ridges).

All three ships maintain an ice thickness watch during the entire time of transiting. Trained observers compare ice being overturned to markings on a meter stick sticking out from the hull.

While the data is recorded (on an iPad?), it is not shared with expedition funders (taxpayers) even though improving navigation safety and satellite products such as cryo2Smos are stated mission objectives. The KD, like the PS and AK, has excellent internet service, the iPad twitter, text and email and AWI hundreds of terabytes of storage.

Some 15 thermistor buoys have been deployed so far during the Mosaic expedition. The data for them is well-organized at Meereis Portal except for time synchronization. The time and GPS lat lon can be downloaded as simple 3-column tables and consolidated into a 45 column table from which any mix and match of kml-readable polygons can be made using a concatenate tool and fill-down.  These can be displayed one at a time in GoogEarth and captured for a delaunay-style animation along with their haversine separations. Details left to Tor B.
Title: Re: MOSAiC news
Post by: blumenkraft on December 19, 2019, 05:43:16 PM
I was wondering why the MOSAIC podcast "Arctic Drift" is in German. Now i heard Markus Rex speaking English and i'm wondering no more.
Title: Re: MOSAiC news
Post by: blumenkraft on December 19, 2019, 05:55:54 PM
Damn, i want that jacket!
Title: Re: MOSAiC news
Post by: A-Team on December 20, 2019, 01:04:25 PM
M Nicolaus has a strong background in sea ice physics with a special interest in autonomous buoy arrays and underwater ROVs and took part in N-ICE 2015. Some of his 2018-19 publications are attached below. Like C Haas, he supports open research and better communications with the public. (We shall see.)

The ROV site had to be taken out of action yet again due to new shearing, floe leads and pressure ridges that they are blaming the KD track for. We don't have a close-in map of KD movements because S1AB is spotty and barely has enough resolution to catch ephemeral tracks.

No maps of the revised Mosaic ice camp or summary of instrument status during leg 1 have been provided for months; only the vaguest text indications have been provided so far (eg, MET shifted 0.6 km past the bow).

The Dec 19th photo at 'follow mosaic' shows the KD leaving. The condition of the ice is shocking -- the full-size picture is worth a close look.

One horrific mistake I see over and over at Meereis  and Mosaic sites is confusion between data and information. It is completely irrelevant that they collected 26 terabytes of data (enough to fill a $175 external drive for an iMac). The web cam at my birdfeeder provides much more than that yet very little information (sparrows like sunflower seeds). What information is in those 26 TB ... soot from the PS smokestacks makes aerosol monitoring unworkable? And how is the short shelf life of Arctic information accounted for if publications are put off to 2023 as planned?

Ice-tethered platforms & ROV, Progress report
M Hoppmann, B Rabe, M Nicolaus, F Wenzhöfer, P Anhaus, D Scholz, ...

Sea-ice Properties derived from Ice Mass-balance Buoys using Machine Learning
L Tiemann, M Nicolaus, M Hoppmann, M Huntemann, C Haas

Seasonal evolution of snow depth on Arctic and Antarctic sea ice from Snow Buoy measurements
M Nicolaus, S Arndt, M Hoppmann, C Katlein, N Maaß, L Rossmann, ...
EGU General Assembly Conference Abstracts 20, 7666

The Sea Ice Drift Forecast Experiment
H Goessling, A Schweiger, E Blanchard-Wrigglesworth, T Krumpen, ...
EGU General Assembly Conference Abstracts 20, 16546

The Arctic Cloud Puzzle: Using ACLOUD/PASCAL Multiplatform Observations to Unravel the Role of Clouds and Aerosol Particles in Arctic Amplification
M Wendisch, A Macke, A Ehrlich, C Lüpkes, M Mech, D Chechin, ...
Bulletin of the American Meteorological Society 100 (5), 841-871
Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter
T Krumpen, HJ Belter, A Boetius, E Damm, C Haas, S Hendricks, ...
Scientific reports 9 (1), 5459
Title: Re: MOSAiC news
Post by: gerontocrat on December 20, 2019, 01:38:32 PM
One horrific mistake I see over and over at Meereis  and Mosaic sites is confusion between data and information. It is completely irrelevant that they collected 26 terabytes of data (enough to fill a $175 external drive for an iMac). The web cam at my birdfeeder provides much more than that yet very little information (sparrows like sunflower seeds). What information is in those 26 TB ... soot from the PS smokestacks makes aerosol monitoring unworkable? And how is the short shelf life of Arctic information accounted for if publications are put off to 2023 as planned?

As the tailor said to the customer...
"Never mind the quality, Sir. Feel the width!"
Title: Re: MOSAiC news
Post by: blumenkraft on December 20, 2019, 04:23:09 PM
This GIF is showing the departure of the Kapitan Dranitsyn.

The dotted box shows an ambiguous area where the KD may have had temporary difficulty finding an easy route. Otherwise, a straight track means the captain did not rate obstacles worth avoiding (ie no issues presented buy thick ice or pressure ridges).

Looks like the KD was stuck after that for a few hours?
Title: Re: MOSAiC news
Post by: blumenkraft on December 20, 2019, 04:43:21 PM
Nice. I just found a list of weekly reports!

Link >>

(Of course, the "Measurements" section is empty... :( )
Title: Re: MOSAiC news
Post by: blumenkraft on December 22, 2019, 08:44:42 AM
Pretty clear I5 band (Infrared) picture came in.

Huge crack in the east.
Title: Re: MOSAiC news
Post by: blumenkraft on December 22, 2019, 04:28:41 PM

Nature’s 10 is the journal’s annual list of ten people who mattered in science this year. Markus Rex, Head of MOSAiC, is on the list “Ones to watch in 2020”.
Title: Re: MOSAiC news
Post by: blumenkraft on December 23, 2019, 12:03:32 PM
We are moving south-west ATM.

Edit: Ah, and apparently we had northern lights.
Title: Re: MOSAiC news
Post by: blumenkraft on December 24, 2019, 10:07:46 PM
Geo-colour & I5 band

More south-west movement and new cracks around.
Title: Re: MOSAiC news
Post by: blumenkraft on December 25, 2019, 08:13:52 AM
I'm supposed to study PHP. So i did what people do in this situation: Procrastinating by playing around with the RAMMB-SLIDER.

I found what i think to be the best setting to track the Polarstern if you don't like or know how to interpret the infrared bands.

This is M13 (4.05 µm "Fire Detection") & Geo-Color. It is obvious what the clouds are while also seeing the cracks and of course the bright dot that is the Polarstern.

Link >>

Title: Re: MOSAiC news
Post by: blumenkraft on December 27, 2019, 06:28:15 AM
Yesterday we moved north-east.
Title: Re: MOSAiC news
Post by: blumenkraft on December 28, 2019, 06:10:08 PM

The latest radar images of the ship’s surroundings

Link >>
Title: Re: MOSAiC news
Post by: blumenkraft on December 29, 2019, 01:00:36 PM
The position of the PS via Day&Night band, 60 frames, 51-minute increments.

I chose this band because it's the most complete set of frames.

We are moving very slowly in the wrong direction ATM (North is right).  :-\
Title: Re: MOSAiC news
Post by: A-Team on December 29, 2019, 11:55:48 PM
Two significant new offerings at Meereis Portal: the interactive buoy GIS display discussed earlier in #437 and release of sea ice motion radar cam scenes looking out from the Polarstern bridge  (link in #454).

Note the comparable radar on the antique RV Lance digitized an image a minute with a 360º view and range of 9 km during N-ICE2015 whereas with Mosaic the 280º field of view excludes the Ice Cam, reports every six hours (ie at 1/360 the frame rate) with only 5.2 km of range.

Note the 06:00 daily nadir S1AB coincides with the 06:00 oblique ship radar, meaning the two cannot be color-composited though the Sentinel at 200% can fill in the missing ice camp (2nd image).

We looked at marginal ice zone action and a radar cam article back in #83:

Presumably the PS has more sophisticated radar than they're letting out because you can buy better recreational boating radar for a few $k on ebay. The blackout on the Ice Camp could plausibly be attributed to rfi with all the other equipment out there. Dedicated instruments and strain panels monitor conditions there but that data has not been shared except anecdotally (and via S1AB analysis here). 

The full dataset is sent daily over the Polarstern's fast internet (still being denied on Dec 27th) to Bremerhaven where it is bundled into rolling windows of two weeks extent (14 days x 4x = 56 frames served as slow avi movies). The archive goes back to Nov 1st but increments daily. No explanation has been offered for the delayed upload on Dec 15th and first mention on "Follow Mosaic" on Dec 28th.

It's not clear if the Oct 4-31 floe motion is being held back or just delayed. The ice would have been in total chaos back then going by the chaos of the last two months in strengthened thickened ice, below. The minute-by-minute research grade terabyte dataset is not available which is appropriate.

The archive began duplicating the avi with identical and fully interchangeable m4v formatted videos on Dec 15th, reminiscent of the head-scratching duplication of 'mosaic_multisensor' with all-purple sea ice concentration overlays.

The file sizes are kept to a few MB using avi even though they are really just gif slide shows. ImageJ is very unusual in having an avi reader. This opens them as image stacks, with helpful options for grayscale and 180º rotation (to better align with S1AB and other 'greenland down' satellite imagery).

ImageJ is also very good at sharpening the periphery, reducing the overly bright returns from ice near the bow, changing palette, and concatenating bimonthly bites into a single image. Surprisingly converting the avi to forum-friendly mp4 at give as very helpful further reduction in file size.

The smaller gif at the bottom features the dramatic lead that opened a few km south of the Polarstern on 15 Dec 2019. Moderate benefit can come from contrast enhancement, sharpening and an indexed palette.

The bridge radar is confusing on first view, so set it on loop and (after download) click repeatedly on the double arrow to speed it up. The white scale bar is intrusive. Its central tip is the center of the fixed polar coordinate frame in which the bridge radar is stationary. It isn't clear if the bow-stern axis is also fixed nor if it points north-south. (The integrated navigation system records this information but it is not provided.)

The timestamp would be better with seconds and minutes rounded away, repositioned lower into vacant black space. The stern may wag about causing the view to shift when little is actually happening; the ship is also drifts and rotates quite a bit over the 60-day time frame of the video.

Overall, it is astonishing that scientists have been able to keep equipment deployed on the ice running at all. Actually, we have no idea how Leg 1 data collection went as little can be gleaned from short :) reports.

Expeditions like this were already being squeezed out of the picture by advanced calibrated satellites, massive buoy arrays and long range autonomous gliders. The ice seems too far gone for the floe platform concept to work.

Just because the ship will be drifting aimlessly until early January (when winds sweeping up from Siberia will finally send it Fram-ward) doesn't mean the ice will be quiescent. Worse, record lows have arrived with -34.7ºC recorded on 19-12-28 at 23:00 utc, making damaged equipment that much harder to repair.

And it seems that we are far short of the 8-10 extreme weather events expected in winter at the Polarstern's location (below or see #368). It's been quite stormy in the North Atlantic but so far extreme weather has not moved up past Svalbard to any extent.
Title: Re: MOSAiC news
Post by: uniquorn on December 31, 2019, 02:31:46 PM
drift update dec16-31. Overall drift is quite small over the last 2 weeks.
Title: Re: MOSAiC news
Post by: gerontocrat on December 31, 2019, 05:35:44 PM
NSIDC's MOSAIC website gives you a weekly log of where the PolarStern is/was

Qu: Goosey goosey gander, wherewil you wander?

A: Since October, not very far.

Title: Re: MOSAiC news
Post by: blumenkraft on December 31, 2019, 05:48:14 PM
Here for a year.

Bury your hurry.
Title: Re: MOSAiC news
Post by: A-Team on December 31, 2019, 10:47:46 PM
NSIDC's MOSAIC website
That has nothing to do with NSIDC. It is educational material for teachers of kindergarten-6th grade put together by CIRES from 'follow mosaic' blurbs. Note it makes no sense to give lat lon out to two positions but not the timestamp when longitude can jump by 4º in a single day.
Since October, not drifted very far. Drift quite small over the last 2 weeks.
Correct. The Polarstern is way behind their anticipated location for this date. This matters, as drift across the Eurasian Basin was one of the three core pillars of the expedition. So far, even including the 45-km wide swath, very little of the Arctic Ocean has been sampled.

The second pillar, evolution of a fixed floe and its surrounding ice over a full annual cycle, has effectively been abandoned as the floe is already in shambles. You can see that from S1AB daily turmoil on the Mosaic floe, from the nrt ship forward-looking radar, and from plaintive postings about downed deployed equipment.

The third, continuous ice, water and atmospheric observational data not obtainable from satellite, buoys or autonomous gliders is in wait-and-see mode as it's not clear what fraction of the time deployed instrumentation has been operational. Since each year of ice weather is one-off, especially these days, the biggest benefit may come from calibration of satellites and better understanding of what autonomous tools are reporting.

The Polarstern will finally be getting a couple days of favorable tailwind (below) but winds are not strong enough to move the multi million sq km block of MYI (Modis/Ascat up-forum) sitting between them and the pole.

I foresee them reaching 87.1ºN (still 335 km short) and perhaps 112ºE which is actually more Fram-favorable as circumpolar drift has been far more frequent than transpolar over the last decade.

On nullschool, checking the 'grid' overlay helps visualize the angle of wind relative to circles of constant latitude. The ice generally moves 'to the right' of streamlines, per Nansen. So it is only in the latter frames that the wind is providing a poleward stress component.

Here the position of the ship needs to be adjusted frame by frame to account for how much drift has taken place as the forecast progresses. Otherwise the wind bearing and speed won't be appropriate to the actual position. Those can be estimated quite well by finding an applicable period of the wind speed and bearing on the 1940-line ship hourly wx report. An iteration might improve the drift forecast,

The second attachment below provides 168 high precision locations of the PS from mooring until today along with built urls to S1AB and GFS and rotation angles to put north up for the given location (so as to match orientation of the dramatic new observation deck radar).

That archive is being actively kept up though the 1024x1024 size of the rolling avi video needs adjustments to display here. Dec 29th is missing entirely. Hopefully the missing month of October will eventually be supplied. It would be of interest to annotate the jigsaw puzzle action to see if fissures repeat over time and how big events correlate with GFS wind stress.

Technical note: This unusual radar imagery is sub-optimal as archived, mostly because it is too bright near the bow, too dim overall and too fuzzy on the periphery. These problems are intrinsic to how the radar works.

However because ImageJ has an avi frame reader, complex video editing software is not needed and some yet-to-be determined combination of our usual tools (frame deletion, cropping, resizing, moving of timestamp, adaptive contrast, unsharp mask, gamma-corrected contrast, indexed palettes etc) can improve the product.
Title: Re: MOSAiC news
Post by: A-Team on January 01, 2020, 05:56:32 PM
Below, another version of the Polarstern's drift so far based on once-a-day precise S1AB positions from the csv attached above. We are seeing a great many wheel reinventions but few improvements on what Google Earth freeware has long provided in web browser form from a quick template paste and click. The kml file has to be attached as txt for the forum.

The ascat mp4 shows the Polarstern's position within plastically deforming ice. Actually the ice is quite strong and brittle at sustained -30ºC temperatures but appears almost liquid on ascat because over-rafting, ridging and lead opening take up any slack.

The Polarstern's drift has been contained so far within the small rectangular overlay; the last frame shows daily drift positions. While the resolution is much less than S1AB or bow radar, ice motion still appears quite dramatic at the ship's location even at ascat's scale.

Cryo2Smos ice thickness has progressed up to what Mosaic thought it would be back on Oct 1st, three full months ago. The regional buoy array could provide more accurate pointwise data on growth; thickness depends on where and how the buoy was initially installed. Snow depth, if any, slows transmission of cold from the air into the ice.

Boundary conditions, in this instance Greenland, can very much constrain ice response to wind stress.  Right now, with 15 straight hours of 8-10 m/s wind from a ship wx station bearing of 120º, the Polarstern should be (and is) moving poleward and to the west.

However there is a lot of thick ice ahead of it and that ice is pressing up against solid land. This means less actual displacement than if the wind were still at 240º. The wind field is not homogenous however and has been moving ice rapidly along north Greenland towards the Fram Strait (above) which may ease the push-back..

Folding in forecast uncertainty, it isn't feasible to predict ice motion more than 3-4 days out. Broad-brush seasonal weather forecasting may be on the horizon but halfway reliable predictions of trans- or circumpolar drift are lacking, even as hindcasts. Buoy trajectories are largely inapplicable to Mosaic drift because only 0-1 are launched per year in the central Arctic Ocean and those mainly in early August.

Sea ice motion will be a major driver of the 'end game' for Arctic sea ice; our lack of understanding effectively derails all attempts at predicting this from trend lines.
Title: Re: MOSAiC news
Post by: blumenkraft on January 01, 2020, 08:08:57 PM
Two decades in one GIF.

60 frames, 51-minute increments.
Title: Re: MOSAiC news
Post by: uniquorn on January 01, 2020, 09:33:07 PM
update on the simb ice mass balance buoys. Two of them were deployed onto thinner ice and appear to be having some trouble. Perhaps simb4 has tilted or fallen.

Also of interest are two meereis Rbuoy charts from buoys with thermistor chains. These show surface temperature, the temperature gradient through the ice and water temperature below the ice. There are 208 sensors spaced at 2cm intervals. It's not easy to tell ice thickness from the charts but by counting the number of thermistors from today's yesterday's surface temperature at ~-32.2C to water at -1.8C they indicate ice+snow thickness of 1.1m to 1.2m

MoreSome old info from Mario Hoppman on temperature chains. cffr
Title: Re: MOSAiC news
Post by: A-Team on January 01, 2020, 11:18:56 PM
That poster concept above is from M Hoppmann, 05 Apr 2017. It is outdated in the sense the thermistors today do not need the ship LAN and can report cheaply to other satellites than Iridium. I do wonder about "powering by regular lead batteries" which inevitably get dumped as the floe melts.

Chinese researchers have developed better, cheaper thermistor electronics and have deployed over 50 in the Arctic Ocean over multiple years.

Almost looks like they are pushing a small wooden dinghy along rather than a nansen sled. Hopefully the 'remote sensing equipment' being relocated away from a new pressure ridge or open lead (?)does not need the jumble of cables and twisted wires (bottom center) to function.

Temperatures plus wind chill have made it unsafe to take gloves and face masks off to repair deployed equipment, though conditions are not more extreme than those seen (somewhere!) in the continental US this time of year

The Nov-Dec close-up of sea ice motion around the Polarstern is a stretch for Ascat resolution but conveys the instability of the ice pack on a daily level.

Just testing below whether the Meereis Portal m4v format loads to forum display. No. Even though Neven has it enabled. It is just an iTunes DRM version of mp4. They are duplicating their avi files with it. Changing extension to mp4 is supposed to work but does not. Lots of threats posted at meereisportal under German copyright law, not allowed in the US in view of NSF (taxpayer) funding. Avi is best for us because ImageJ has a frame reader only for it.
Title: Re: MOSAiC news
Post by: uniquorn on January 03, 2020, 04:33:39 PM
Radar animations appear to have stopped at dec31. Hopefully they will resume.

drift update jan2-3, some data is missing over the new year. Some white space filled with latest polarview, KapD exit trail still visible.

Some may have use for animation data attached
Title: Re: MOSAiC news
Post by: A-Team on January 03, 2020, 07:00:30 PM
There's been a good series of Leg 1 blogs up at UA Fairbanks by R Rembler that supplement those of M Shupe and BBC. These represent all that we really know -- or will ever know -- about how sea ice motion is affecting operations on the Mosaic floe.

AWI has censored and silenced all other sources in favor of relentless, uninformative :). The Carl Zeiss culture of quality is long gone; Germany today is VW diesel, AWI information management, and 21 of 103 buoys dead within days including 8 set out by AWI and 2 of 6 placed en route by the Kapitan Dranitsyn. An additional 24 floe buoys have been silenced and do not report to the international buoy tracking service.

These buoys aren't AWI's property as they seem to think; the buoys, the ship, all the equipment and the data itself are owned by taxpayers who funded Mosaic. AWI itself does not have one pfennig of its own.

As an aside, note the KD's exit swath is still quite visible today on S1AB. Scientists from Leg 1 just disembarked in Tromsø on Jan 1st; no information is available on what they observed in transit (ice thickness is always measured).

Big plans for daily bow radar release have seemingly foundered: still no coverage of Oct 4th to Oct 31, all coverage stopping on Dec 31, no response at all to polite inquiries from the designated on-shore scientific contacts, web page promises have been shelved, and annoyance expressed by the Meereis Portal communication leader that the (non-forum) public dares question map quality and delays.

Apparently quite a few outside scientists are unhappy with the kindergarten-level portal; they may not be aware Germany invented kindergarten back in 1837.

In other words, download a complete bow radar set now before it disappears forever (or gets locked down in a threatened proprietary format). It takes five to make a complete non-overlapping set: 20191101_20191114.avi, 20191115_20191128.avi, 20191201_20191214).avi, 20191215_20191228).avi and the largely redundant 20191218_20191231).avi. These are small files found at

Open each as grayscale with the free Imagej frame reader. Do not check 'virtual stack'. Under Images --> Stack --> Tools --> Concatenate, join the avi in temporal order, save as avi or gif. In ImageJ, Command-Shift-D pauses to let you to duplicate any subset of frames, for example ones flanking a certain date or all those showing major ice action.

18 Nov 2019 - A big storm By Rob Rember

… On Friday 15 Nov 19, we were notified that the weather was going to get substantially worse over the weekend and that by Sunday winds would exceed gale force (14 m/s). On Saturday the 16th, we quickly went out to sample the first- and second-year ice sites in case our Monday coring was cancelled.

The storm came on Saturday night and continued all day Sunday the 17th as predicted. Winds consistently exceeded gale force for most of the day. The ice opened and closed in front and to the side of the ship several times. At one point from the bridge there was 50 m of open water with waves beginning to form, while on the [starboard] side the ship continued to be moored to the ice floe.

There were large cracks that opened all over our local area (ocean city, remote sensing, ROV site etc.) that stayed open for many hours. We had substantial damage to several power lines as the flow separated and came back together.

This morning the wind is still up around 15 m/s and the damage assessment has begun. We surveyed our coring sites, they are completely intact and can be reached with minimal detours. UAF science has luckily fared well. Other sites will require some major rebuilding with 700 kg power nodes tipped over as ice drifted/sheared and pulled on cables that were fixed to the power distribution hubs.

In the next 30 minutes we will have a meeting to discuss the new steps. The ice is still moving and we are not in a stable situation to begin rebuilding. Even so, the UAF team will head out this afternoon to continue the sea ice coring times series we started approximately a month ago.

I looked at GFS winds, sailwx, ship weather, Rammb, bow radar and seven enveloping S1AB images for confirmation, first noting a 2º longitude lurch in Polarstern position overnight. The big ice radar action came later, on the 19th-20th under continuing strong and strongly shifted winds.

The explanation: ship weather is measured on high and provided as hourly averages so ground level gale force gusts are depracated; GFS 'surface' winds are non-observational so the 1000hPa may be better. Both are in good agreement with Rembler's blog.

Bow radar captures 360º but 80º has been blacked out, notably the entire Mosaic floe and near-ship instrument area observed by Rember whose times, dates and wind speeds may be off because the Polarstern does not use UTC and he does not use the metric system.

I've observed a puzzling non-grasp of causality at Mosaic. Arctic winds and ice motion stress are basin-wide, not local; nothing can be predicted from ship wx point forecasts alone. One glance at the GFS forecast -- a strong, sharply curved cyclone passing repeatedly over the Polarstern at different bearings should have warned them (indeed we called it out here well in advance). It is not homogenous high winds that cause destructive ice motion but high curvature and rapid temporal change in streamlines and their bearings.

Available S1AB: note imagery from the key date of Nov 16th is missing
S1B   2019 11 22 0546   85.7341   120.8084
S1B   2019 11 22 0408   85.7353   120.8119
S1B   2019 11 22 0230   85.7352   120.8192
S1B   2019 11 21 0643   85.7429   120.9425
S1B   2019 11 21 0327   85.7446   120.9824
S1B   2019 11 20 0602   85.7656   121.6001
S1B   2019 11 20 0424   85.7643   121.5311
S1B   2019 11 19 0700   85.8011   120.5766
S1B   2019 11 19 0521   85.8020   120.4943
S1B   2019 11 19 0343   85.8009   120.4512
S1B   2019 11 18 0619   85.8510   120.7805
S1A   2019 11 18 0530   85.8556   120.8340
S1B   2019 11 18 0441   85.8609   120.9092
S1B   2019 11 17 0538   86.0462   122.4998
S1A   2019 11 17 0449   86.0532   122.4685
S1B   2019 11 17 0400   86.0595   122.4405
-+-   2019 11 16 0600   86.1243   120.4086
S1B   2019 11 15 0554   86.1891   118.3766
S1B   2019 11 15 0416   86.1897   118.3522
S1A   2019 11 15 0327   86.1897   118.3386

Hourly ship weather: 60 straight hours of >10 m/s (last column)
86.1   122.4   17 11 19   0000   15
86.1   122.4   16 11 19   2300   16
86.1   122.4   16 11 19   2200   13
86.1   122.3   16 11 19   2100   14
86.1   122.2   16 11 19   2000   16
86.1   122.1   16 11 19   1900   16
86.1   122.0   16 11 19   1800   19
86.1   121.8   16 11 19   1700   19
86.2   121.6   16 11 19   1600   20
86.2   121.5   16 11 19   1500   21
86.2   121.3   16 11 19   1400   20
86.2   120.9   16 11 19   1200   19
86.2   120.8   16 11 19   1100   18
86.2   120.6   16 11 19   1000   17
86.2   120.4   16 11 19   0900   17
86.2   120.3   16 11 19   0800   17
86.2   120.1   16 11 19   0700   16
86.2   120.0   16 11 19   0600   15
86.2   119.9   16 11 19   0500   14
86.2   119.7   16 11 19   0400   12
86.2   119.6   16 11 19   0300   12
86.2   119.5   16 11 19   0200   12
86.2   119.4   16 11 19   0100   13
86.2   119.3   16 11 19   0000   13

GFS nullschool cyclonic winds:
245° @ 11.2  m/s  2019/11/16/0000Z
250° @ 12.9  m/s  2019/11/16/0300Z 
250° @ 14.3  m/s  2019/11/16/0600Z
250° @ 13.5  m/s  2019/11/16/0900Z
255° @ 15.8  m/s  2019/11/16/1200Z
260° @ 14.1  m/s  2019/11/16/1500Z
275° @ 15.0  m/s  2019/11/16/1800Z
290° @ 11.1  m/s  2019/11/16/2100Z 
320° @ 13.4  m/s  2019/11/17/0000Z 
310° @ 10.7  m/s  2019/11/17/0300Z
315° @ 11.5  m/s  2019/11/17/0600Z 
325° @ 11.6  m/s  2019/11/17/0900Z 
355° @ 10.1  m/s  2019/11/17/1200Z 
350° @ 13.3  m/s  2019/11/17/1800Z 
360° @ 14.7  m/s  2019/11/17/2100Z 
360° @ 14.9  m/s  2019/11/18/0000Z
005° @ 16.4  m/s  2019/11/18/0300Z 
005° @ 13.9  m/s  2019/11/18/0600Z 
010° @ 14.4  m/s  2019/11/18/1500Z 
010° @ 10.2  m/s  2019/11/18/0900Z
Title: Re: MOSAiC news
Post by: blumenkraft on January 04, 2020, 09:39:14 AM
60 frames, 51-minute increments, D&N band

More of this please! :)
Title: Re: MOSAiC news
Post by: A-Team on January 04, 2020, 06:45:25 PM
if we all clap our hands, Tinker Bell can fly again (?)
Nothing to cheer about here, the Polarstern is drifting into a a long-stagnant zone (per Ascat), getting ever farther behind the eight-ball in terms of hitting their target next October.

Random drift north is not to be conflated with systemic transpolar drift -- the weather pattern for the latter is specific, very different, and yet to kick in.

RAMMB is cool but what is it good for? Not aurora borealis (via reflection on clouds); nullschool has a great tool for that already under its ‘Space’ setting.

Real time Polarstern position? The ship already posts its lat lon online once an hour in real time, that's 2000 times since mooring. It's easy to heuristically predict the ship's position 3-4 days ahead using GFS-ns winds as on Dec 31st in #460.

Some of the buoys post much more frequently than the 51 minute JPSS satellite and some have 5 dp of positional data. However the public has been denied access to the really high accuracy/high frequency ship and floe buoy data.

We also have four dp precision lat lon posted 2-3x a day at 41 m S1AB resolution attached here back to Oct 4th, 175 scenes to date. RAMMB can’t be used to patch gaps in S1AB coverage (eg Nov 16th) because its archive only goes back two weeks.

2020 01 04 0538  8  86.9848 115.4547
2020 01 04 0400  8  86.9780 115.4551

Determining the maximal resolution setting of RAMMB requires a scale screenshot that includes both the 85º and 87.5º parallels. Those are separated by 698 pixels along the 115º meridian which has length 278.0 km between those two latitudes. Thus the maximal resolution of RAMMB is 398 m/pxl.

However clouds and atmospheric turbulence lead to a 5x5 pixel blur/wobble in the Polarstern's dot. Picking the central pixel gives a 3x3 uncertainty so the actual ability to determine ship latitude is 1200 m, so about 30x worse than the resolution of S1AB which in turn is 2x worse than bow radar.

On 20-01-04 08:00, the PS was at 87.0,115.4 which means 37 pixels between 115 and 117.5, the next graticule line over on RAMMB maximal resolution. That distance is 14.55 km. This means that that the longitudinal resolution is about 0.1º, perhaps a slight improvement on the censored location at AWIwx.

Ship radar images of the last 14 days. Actual radar-image sequence of RV Polarstern from the last 14 days. More videos can be found here. From January, these videos will be available here by a drop down menu.

Live stream from on board: The latest radar images of the ship’s surroundings. Every day, here at we show from now on a video sequence of ship radar images. The RV Polarstern’s marine radar systems will continue to operate throughout the drift phase and images produced by the system are transmitted to Bremerhaven several times a day.

The imaging system, which shows Polarstern in the centre of the screen, offers vital information on floe movements, deformation and formation of cracks in the ship’s immediate vicinity.
Well, that is a decent plan but higher-ups may have killed that initiative already. It's only a matter of time (days?) before the above text and two month archive are deleted from the Meereis Portal server.

My guess: some antique boomer at AWI is obsessed with putting all Mosaic reports into a thick special-issue journal in 2023. However there are hardly any print journals left now and there won't be any by then.

Like open source buoy data, bow radar can be processed as it comes in, published in a timely way, and contribute to our understanding of icepack deterioration in the Arctic Ocean. In 2023, no one will have the slightest interest in 2019-20 sea ice motion.

Alternatively, all is well and the delay in posting is due to the lead scientist on bow radar only returning to port Wednesday on the KD and just back at work on Monday. I looked at their bow 2017 bowradar paper from the N-ICE2015 five month drift in the very different marginal ice zone (, earlier work cited there, and the 19 forward citations.

They could readily clone this paper for leg 1-2 and then again for legs 3-4 and 5-6. However it's not clear whether ice motion metrics really describe what is going on (see below), nor whether seasonal or year-to-year comparisons can be made, mostly because no previous data exists for the Polarstern's location.

SHEBA, an earlier year frozen into the ice, took place 22 years ago; did the Des Groseilliers even have bow radar then, was it strictly analog, was it filmed, is it archived somewhere online? SHEBA and N-ICE2015 both experienced severe ice motion but more? less? about the same? as the Polarstern is seeing now.

We have a great opportunity to add value to Polarstern bow radar because  it is optimized for the bridge when the ship is underway, not for later perusal. Right now it is over-exposed close to the ship where the return signal is strongest (radial contrast mask?), blurry on the periphery (radial unsharp mask?), higher resolution close in (better detail in 2-3x scale enlargement), offered in grayscale (more interpretable in indexed palette?) and so on.

Still, making a 2x-invert pair below for the tight cyclone of 16 Nov 2019. I don't see a path forward to really describing the complexity of sea ice motion, especially the repeated openings and closings of the same floe line, causing multiple collisions in the same pressure ridge. The extent of ridge venation is just astonishing at the resolution and incident angle of bow radar.

Polarstern helicopters could be imaging the bow radar surface elevations every week with lidar. This is imperative for determining ridge elevation and change. The ROV could be measuring keels from below (though it has scarcely been operable). Lidar data is apparently taken but not disclosed, other than leaked, unscaled, undated, ungraticuled images such as in Rembler's October 23 blog. The blue may just be over-tint on grayscale DEM but with the noxious overlays and scale again not provided(!), it isn't too useful.

The Jan 2020 lidar (airborne lidar scanner ALS) came back with some new cracks and ice dynamics in the heavily instrumented L-site. We have no idea where the site is or where new/old cracks map; no lidar has been released. The L-site is off-limits to bow radar. Its past and current locations have not been released.

Were buoys deployed within the bow radar viewing fame, can we overlay tracks on the Nov-Dec footage, what became of buoys during the storm chaos, is the turmoil seen representative of a larger area?
Title: Re: MOSAiC news
Post by: blumenkraft on January 04, 2020, 06:54:01 PM
... Not aurora borealis...

But you can! :)
Title: Re: MOSAiC news
Post by: blumenkraft on January 04, 2020, 07:19:29 PM
Thus the maximal resolution of RAMMB is 398 m/pxl.

They claim:

Select the map and domain to fit the native resolution of the data. The images were plotted using IDL's Lambert Azimuthal projection, which I think has the least amount of distortion and does the best job at maintaining the native resolution of the instrument. The size of the domain was chosen so that each pixel in the resulting image represents the ~375 m resolution of the high resolution imagery bands, while trying to keep the resultant file size down. (These results are animated GIFs over 20 MB in size as it is.)

Note the ~.

Link >>
Title: Re: MOSAiC news
Post by: A-Team on January 04, 2020, 10:24:45 PM
This is the Mosaic forum. If you can find an application for RAMMB, great. Otherwise perhaps start a separate forum for it?

The aurora borealis is off-topic and done vastly better on nullschool; on the Polarstern, people report spending two months at sea without seeing even a single star because the ship has to be so bright. Your image lacks corroborative evidence yet that should have been easily available because the AB view (from OVATION / SWPC / NCEP / NWS / NOAA) updates every 10 minutes or 5x the frequency of RAMMB.

Lightning flashes? Rare in the central Arctic but done infinitely better by a Finnish company detecting weak radio waves. They recently compiled a surprisingly number of AO events out of their vast global archive. RAMMB, can't go back in time. That's a big problem for PolarView too.

Snow vs rain? Yes, with interpretation but that is somewhat a false dichotomy. The Polarstern has lots of snow buoys set out and much fancier ice camp equipment measuring density, internal melt, flooding history, salinity, impurities and so forth. Not going to get at those with RAMMB.

Better time resolution of lead opening and closing than S1AB? Possibly, though RAMMB resolution is not a good match to intrinsic dimensions of ice features. Six-hour bow radar shows how much S1AB itself misses, despite its 30x better resolution than RAMMB.

Even recreational bow radar is digitized once a minute so meereis could be providing 3600x the time resolution or 51x better than RAMMB resolution. Once an hour is probably the sweet spot in terms of file size and correlating with hourly wx data and 3-hourly GFS. However for abruptness of kinematics, a bit of once a minute or continuous analog would be interesting.

Storms? That seems to have been the motivation underpinning RAMMB. For the Polarstern, what we most need are surface wind forecasts and surface roughness. The top priority would be getting ECMWF again; windy dropped the Arctic because there weren't enough clicks.

Transit of relief icebreakers? Yes if only we knew why their progress varied: were they encountering thick ice, stopping for polar bear photos, or putting out buoys? So far none of the ships have made their logbooks or ice thickness data available. Here 51 minutes is better than S1AB burst mode but still not great for velocity estimation. Then there are is the issue of no one digitizing location off RAMMB frames and estimating error with that.

As explained here many times, Lambert azimuthal is used is for its equal area pixels, not because it represents the AO with "less distortion" than conformal polar stereographic (angle preserving). PS, Greenland down, is standard in almost all direct satellite products we use. With netCDF we can interconvert in Panoply.

Lambert thus seems a bad idea because each round of interconversion degrades already blurry data, ie initial PS to RAMMB to PS for overlay say with WorldView night bands or S1AB leads loses detail we cannot afford to lose, the roundtrip is appalling.

The bow radar products above exceeded 150 MB as gifs; 20 MB gifs are a nothing-burger. Maybe RAMMB could offer mp4 and ditch the horrific download code too. A 10 terabyte external drive is very affordable (skip starbucks, make your own coffee and avocado toast).

You might also consider basic contrast adjustments before posting -- two or three clicks can vastly improve clarity of RAMMB animations. For leads and ridges, wavelength matters. If day'n'night is looking at escaping heat in infrared and active radar is looking at roughness backscatter, the two won't correlate that well.

The RAMMB project deserves our applause for putting a lot of opaque satellite channels within practical nrt reach. I am open to it having an application to Mosaic but just don't see what that is. It's hard to find an angle where it is 'best in category'.
Title: Re: MOSAiC news
Post by: blumenkraft on January 05, 2020, 07:12:28 AM
This is the Mosaic forum. If you can find an application for RAMMB, great. Otherwise perhaps start a separate forum for it?

Are you serious? A GIF showing the Polarstern is off-topic in the MOSAIC thread? Is it that what you are saying?

The aurora borealis is off-topic

You said it's not visible and i showed a pic where it's visible. That's all. Nothing to be concerned about.

I appreciate your contribution A-Team, really. But with all due respect, i reject your parenting.
Title: Re: MOSAiC news
Post by: castaway on January 05, 2020, 12:32:58 PM
Hey guys, thanks for all the hard-working and posting reports here, and the tips to other reports..
It seems data will be unevenly distributed amongst researchers and not all of it may be public.
There should be enough data to many scientists about the globe to produce results, some results would overlap which should be great as to confirm or put in check one's another methodology and rationale. Even though Polarstern data may be broken into pieces and communal science may be harder than necessary, we shall have an interesting time trying to understand what is going on in the Arctic and more about the recent history of planet Earth.
Title: Re: MOSAiC news
Post by: uniquorn on January 06, 2020, 03:48:15 PM
Polarstern estimated drift calculated from 10/17 distance between p201 and p207. Full path since oct11 at 16frames/sec. (p207 deployed on oct10) ctr
Some may have use for the data attached as csv
Title: Re: MOSAiC news
Post by: Tor Bejnar on January 06, 2020, 06:02:57 PM
Thanks, Uniquorn!
Title: Re: MOSAiC news
Post by: uniquorn on January 06, 2020, 08:28:35 PM
The animation above stretches the limits of the forum and my computer and while it provides a 'feel' for drift some detail is lost, so here is a larger static image with a selection of points in red calculated from S1 images as a rough check. cffr
that glitch at 86.6 looks wrong
Title: Re: MOSAiC news
Post by: uniquorn on January 07, 2020, 11:05:51 PM
Posting this in the hope that the thread gets more hits
Title: Re: MOSAiC news
Post by: be cause on January 08, 2020, 02:45:32 AM
  ' boys a boys ' as we often say here in Ireland .. greetings , blessings and  a whole lot of lovings to a few of my favourite poster buoys .. non p.c. b.c.
Title: Re: MOSAiC news
Post by: uniquorn on January 08, 2020, 03:00:16 AM
drift update
Title: Re: MOSAiC news
Post by: uniquorn on January 08, 2020, 10:49:13 PM
drift update with latlon and distance, a small retrace - see below
Title: Re: MOSAiC news
Post by: uniquorn on January 09, 2020, 11:07:25 AM
retrace of the retrace. No big change in the distances. It would be nice to see how the bow radar looked over the last few days.
Title: Re: MOSAiC news
Post by: uniquorn on January 09, 2020, 11:43:19 AM
The meereis Rbuoys mentioned in post 463 are called radiation buoys. Here are the latest temperature charts from the 11 working thermistor Tbuoys.
Snow ice thickness can be roughly estimated from the charts, thermistors are spaced 2cm apart.

edit: Taking a wider look to view the location of the Tbuoys we can see that the retrace is milder at the periphery, missing t68 completely. T56 looking like it could be quite close to Polarstern.
p201 and p204 left in to help get our bearings.

Title: Re: MOSAiC news
Post by: blumenkraft on January 12, 2020, 01:28:57 PM
Polarstern on an express train right now.
Title: Re: MOSAiC news
Post by: J Cartmill on January 12, 2020, 01:58:28 PM
'Frightening.' Scientists contemplate the melting Arctic
Some thoughts from some of the MOSAIC scientists: (
Title: Re: MOSAiC news
Post by: binntho on January 12, 2020, 02:17:25 PM
I guess I'm a bit slow, but I just realised that Polarstern is German for the North Star!
Title: Re: MOSAiC news
Post by: blumenkraft on January 12, 2020, 03:11:17 PM
Polar star to be precise/literal. :)
Title: Re: MOSAiC news
Post by: gerontocrat on January 12, 2020, 05:53:24 PM
Polarstern on an express train right now.
I think the express train will keep running for a few days more, winds consistently between 6 & 7 m/sec. If anything different, direction will change from towards FJL to towards NE Greenland
Title: Re: MOSAiC news
Post by: A-Team on January 12, 2020, 06:17:59 PM
Fascinating to see those buoys doubling back twice in #481. That took place over 34.5 hours between 09:00 on 07 Jan 2019 and 19:30 on 08 Jan 2019. In a subsequent post, uniq's animation will be cropped down to its relevant half-hourly time frame sand compared to the temporal resolution of hourly ship weather, 3-hourly GFS, 2-3x clustered daily S1AB, and six-hourly bow radar.

What caused the double retrace in buoy motion, did it result in severe ice deformation around the ship, was deployed equipment damaged, can these events be predicted in advance, are they anomalously frequent in this year's ice, what are the consequences for melt season?

The forward-looking ice radar is about the only scientific data released during the first four months of the Polarstern cruise, other than ship weather that comes with severely dumbed down location coordinates.

It came as a burst in late December, got updated to Jan 9th, but went into limbo again (despite MeereisPortal reporting downloads to Bremerhaven "several times a day" over the ship's fast Kepler internet (which AWI continues to deny even having).

They did not repair the Nov-Dec record on the occasion of the Jan 9th update, nor provide the missing Oct 04-31 (because frightening levels of thin ice motion are off-message?). The timestamp is to the second, though the radar takes longer than this to complete its 360º sweep (of which 80º are blocked).

There are 4 forward radars visible in moored images, three on the P-deck over the bridge and one on the very top of the mast (crow's nest) that is being called bow ice radar here. This is mostly used for route-finding when an icebreaker is underway, though the Norwegian N-ICE2015 also used it to capture ice motion during the five winter/spring months it was moored to floes.

You won't ever see N-ICE2015, Chinese, or Russian expeditions (like Mr. Federov's year on a floe) mentioned in Mosaic posts or interviews (eg #484), only Nansen and Sheba. N-ICE2015 covered a lot of the same ground as Mosaic and produced two dozen high quality journal papers  addressing every aspect of sea ice a couple degrees north of Svalbard that significantly undercut the originality of Polarstern science (to appear in 2023).

Ice radar (and the secret ship bearing and location) have by far the best time resolution, on the order of minutes. The 2019 radar images have very irregular timestamps generally 6 hours apart but include numerous anomalies such as 35 gaps out of 295 expected, 7 redundancies, 3 one-off times, days missing altogether, and instances that prove the radar capture has excellent time resolution, instances of 3, 5 and 24 minutes are provided below.

09  Nov 2019   12:00
09  Nov 2019   12:03

10  Dec 2019   06:03
10  Dec 2019   06:27

11  Dec 2019   05:57
11  Dec 2019   06:02

The full bow radar time series to date is attached as a cvs for everyone's convenience. I made this by reading the portal's avi into ImageJ (which skips over frame duplications), cropping out the timestamps, tiling them up, and applying free online OCR to get the times to avoid data entry. OCR works great these days. Another application here is to transcribe the daily 'follow Mosaic' blurbs which they've blocked from text-copy.

It is one thing to observe and another to understand the astonishing level of leads opening, leads slamming back together forming pressure ridges, large blocks of ice shearing past each other and all three types of motion occurring together and repetitively at the same and new zones of weakness.

The idea is to look at what all was going on during especially drastic episodes of ice deformation. First though, are fractures almost instantaneous or do they play out over hours or days? If the former, none of our open source tools have sufficient time resolution. Only non-averaged ship weather (eg wind gusts over 100 km/hr) and ship ice radar have the necessary minute-scale resolution.

However it turns out that most of the events play out over 3-4 days. That gives ~14 ice radar frames, 24 GFS-nullschool Arctic Ocean weather displays, maybe 6 relevant S1AB 41 m images, 42 sailwx condition posts, and 72x3 tracking points of the three close-in deformation proxy buoys.

In terms of spatial resolution mis-match, the bow radar is 10 m/pxl so similar to buoy location precision with S1AB at 400% enlargement barely compatible. At maximal scale, nullschool GFS has a resolution of 2094 m/pxl, meaning the green location circle only moves noticeably after major Polarstern displacements like the one underway this coming week, with wind streamlines taking the PS towards the Barents via the FJL/Svalbard gap.

Thus the release of 1-minute bow radar would be excessive but six-hourly is sub-optimal versus  1-hourly (matches weather readings) or 3-hourly (matches GFS releases). The avi media files are not being prepared properly, meaning three times the time resolution need not result in a larger download archive.

The scientific value of the archive would greatly benefit from regular time sampling, disclusure of the radar wavelength, removal of bulk ice pack rotation (ie use of bow-stern coordinates, not ship vote), clarification of UTC vs changing ship time vs fixed CET, radial contrast improvement (too bright off the bow, too dim elsewhere), zonal unsharp mask (to improve focus of periphery, placement of rounded-off timestamps in a dark lower corner, subdivision of the distance scale, cropping to reasonably lit and focused regions, and coordinated ice thickness and surface elevation overflights.

If the white lines indeed represent pressure ridges (or growing surface roughness lineations), there has been prodigious damage to the FYI surface. This could greatly affect the coming melt season if elevation barriers fragment, delay or prevent melt pond drainage, in turn keep albedo low and insolation high. (Alternatively, melt ponds could drain more rapidly if new fractures from ice motion provide drainages.)

The last two-frame animation shows the dramatic complexification of the ice surface around the Polarstern between 01 Nov 2019 and 09 Jan 2020. The four-attachment limit means the whole avi movie has to go in another post.
Title: Re: MOSAiC news
Post by: binntho on January 12, 2020, 07:55:52 PM
Polar star to be precise/literal. :)
Well, yes. But the star Polaris aka Alpha Ursae Minoris is usually called the North Star in English, nordstjernen in Danish but polstjernen in Norwegian and pólstjarnan in Icelandic, étoile polaire in French and polyarnaya zvezda in Russian and réalta thuaidh ("star of the north") in Gaelic. Interesting how some nations are more precise than others (The North Star always points to the north, i.e. 100% accuracy, but the Pole Star points only towards one of the two poles, a disappointing and totally useless  50% "accuracy").
Title: Re: MOSAiC news
Post by: A-Team on January 12, 2020, 08:04:22 PM
Below, all 252 bow ice radar frames are concatenated into a single image running from Nov 1st to Jan 9th at 36 fps (50% faster than movie film). The frames are about 6 hours apart. Thus the 70 days (1680 hrs or 100,800 min or 6048000 seconds of actual elapsed time have been collapsed to 7 seconds of mp4 video, which is a speed-up of 864,000-fold relative to a person standing on the bow watching the ice move. Glacial motion of Jakobshavn and Petermann have been depicted many times at similar rates on their respective forums.

The timestamp has been lowered to wasted space next to the bow-stern axis scale. Blurred areas on the periphery have been cropped away for a better fit of file dimensions to forum constraints. Dim areas have been preferentially brightened with linear, gamma and adaptive local contrast correction and focus sharpened with slight unsharp mask.  The initial size of 90MB reduces after conversion of ImageJ to 18 MB avi to a final very reasonable 4.3MB mp4, thanks to free online by Munich’s Lunaweb GmbH).

Ice movement can sometimes be seen more easily in a fast inverted image; that is provided at 48 fps with more periphery removed. Be sure to set the controller to loop and move the mouse off the mp4.

One surprising aspect throughout this imagery is that leads close up before they can freeze over, even at very low air temperatures (-30ºC). Open leads historically have been viewed as important direct conduits between ocean heat and its loss in winter to the atmosphere, with refreezing reducing but not totally blocking the effect until an insulating snow cover can build up.

Here none of the leads have stayed open more than a day or two before slamming shut, with refreezing and heat loss having minimal time frames in which to operate. However we don't know how representative the bow radar area is relative to the overall ice pack. Notably, giant lead fields in the Beaufort can stay open for weeks before freezing over.
Title: Re: MOSAiC news English Transcript of Audio Logbook
Post by: psymmo7 on January 12, 2020, 08:17:40 PM
As promised earlier here is an English transcript of the Audio logbook that can be found on the MOSAIC website and is otherwise only available in German. It was posted on the MOSAIC website on Wednesday 8 January, but the recording itself was made on December 14 last year just before the changeover between the first and second leg teams. So it doesn't contain anything particularly newsworthy.

For the record here it is.


Commentator: Artic Drift the Audio logbook.

Markus Rex:  We have now coms as far as eighty-six degrees twenty-six minutes North on the direct route to the North Pole [Ed.: The Polar Stern was at this latitude on either late on 10th or early 11th December]

Commentator: In the Arctic wintery temperatures are gradually being seen. The researchers of the MOSAIC expedition are currently measuring temperatures down as far as minus 30 Celsius. Markus Rex, leader of the expedition explains what further falls in temperature are expected  in the coming days and months.   

Markus Rex: It’s certainly becoming colder as MOSAIC transitions into winter and just in the last few days we reached the lowest temperature record of the season with minus 31 Celsius. Before that the temperatures were mostly above minus 30 or sometimes just touching it. That’s to be expected. The lowest temperatures will be recorded sometime in the period between January and March. The lowest temperatures usually occur in February.

Commentator: In comparison to the expedition of  Fridtjof Nansen, who carried out a similar drift experiment in 1893, these temperatures can be considered warm. The big differences to that time can be traced back to the ice cover and climate change

Markus Rex: Back then Fridtjof Nansen measured temperatures of minus 51 and 52 degrees Celsius at this time of year. Those are temperatures that we won’t observe on this expedition. From all the temperature measurements that we have obtained from automatic drift systems in the arctic we know that temperatures under minus forty-five degrees Celsius practically don’t occur anymore. That’s clearly an indication of change the Arctic is not the same one that Fridtjof Nansen saw then. Our ice is much thinner, it is only half as thick and is therefore very dynamic and full of cracks. The temperatures are higher as well. Climate warming isn’t the first thing that springs to mind, but the change is omnipresent  in the ice and in the temperatures, even if it is  taking place at very low temperatures. It’s not so easy to explain how temperatures below minus 50 could occur in Fridtjof Nansen’s time. After all, even in Fridtjof Nansen’s time the temperature of the ocean under us was only minus one point five to minus  one point seven Celsius, then the water freezes. In other words, we have an enormous underfloor heating system under us an enormous heat reservoir only a thin layer of ice separates from this heat reservoir. The low temperatures are also affected by the ice being thinner and because the ice was thicker in Fridtjof Nansen’s time. He had a thicker insulating layer between the warm ocean and the low temperature air. Our ice layer is thinner, so more heat comes out of the ocean and therefore such low temperatures can’t be reached anymore.

Commentator: The measurements in different scientific experiments are also making progress. Although there is no perceptible difference between “daytime” and “night-time” during the polar night most of the team keep regular working hours. Despite this there are also measurements that are made at night or round the clock.

Markus Rex:
For the most part, we keep usual working hours, simply because the participants also need to take breaks, so we decided to synchronise. But naturally we also want to carry on research round the clock and, in several instances, we are active 24 hours a day. There are scientific reasons for this because there are certain species of organisms in the ecosystem  that have daily rhythms in lower latitudes, migrating back and forth between deeper and shallower layers of water in the course of a day. This raises the question of what these organisms do during the polar night when there is no variation in conditions, when there is no daylight? To investigate that we naturally have to keep making measurements throughout the night.

Our remote-controlled underwater robot is looking at underwater life in the ocean throughout every twenty-four-hour period and I am very curious to know what the results will be. There are really quite a lot of activities that take place during the night. There are automatic instruments that measure continuously anyway and we also have our tethered balloon that takes samples from the 200 metre layer of  the atmosphere above the earth’s surface throughout the night and there are also ocean instruments that operate through the night.

Commentator: The thickness of the ice cover increases continuously during the arctic winter. As a result, larger and heavier equipment can now be brought onto the ice from the icebreaker. This is necessary, in order to prepare for future stages of the expedition, especially when supplies and the exchange of personnel and materials can only take place by air,  which requires a landing strip.

Markus Rex:  As the winter progresses the ice has become thicker. It is still dynamic but, as expected, it is becoming thicker. As a result we have now been able to put our largest and heaviest piece of equipment onto the ice. Our “Pistenbully” [Ed.: also known in English as a snow-groomer] that we use to move other large pieces equipment  and in particular that will be used to prepare the landing strip, that will be used to make changeover between the third and fourth legs of the expedition in March or April. In April, I myself will be here again in April. I have appointed two very experienced colleagues as expedition leaders who will hold the reins in the meantime. In April when I will be back again and  will need the landing strip to get here and the Pistenbully is essential for making it. The ice is now so thick that we were able to put this 16 ton machine onto the ice without the ice creaking and cracking noises and it’s now operating securely.

Commentator: The first leg of the Expedition is now at an end. A new research team is moving into the Polarstern and will carry out the measurements during the next Phase of the expedition. The infrastructural prerequisites for this have been established.

Markus Rex: We have completely finished the construction of the ice camp for our research city on the ice. Every instrument is now in deployment on the ice ..-and working.  We experienced setbacks in the meantime, because instruments fell over or broke down as a result of ice drift causing repeated opening of leads and the formation of pack ice ridges. We have now overcome these setbacks. Everything is functioning and our 30 metre meteorological mast is standing again. Actually, it is only 23 metres high because the rest of it was destroyed, but that won’t affect the measurements, so we will be able to hand over a very well-functioning research city to the participants in the next leg of the expedition.

Commentator: In the course of changing over the teams there was a delay. The Russian supply icebreaker that was carry the new team into the arctic was unable to leave Tromsø harbour because of a storm.

Markus Rex: Just after it set off the Dranitsyn ran into a very, very severe storm. She had to wait in the Tromsø fjord because she couldn’t risk being exposed to the raging waters. There were wind gusts of Storm force twelve. No one would choose to expose themselves to that. So, the  Dranitsyn waited in the fjord for  five days.

Commentator: The Mosaic expedition didn’t miss out on Advent or Christmas either. Despite a shortage of supplies the team enjoyed a sweet surprise.

Markus Rex: On the first and second Sunday in Advent we got chocolate. On St. Nicolaus day [Ed.: 6 December] we all got a little bag with a surprise gift. All of this was extremely pleasing, because the ship had run out of chocolate earlier and we were all extremely happy to get a bag with Christmas cookies, chocolate and all the other nice things. Pretty Christmas decorations were also put up in the messrooms and a Christmassy atmosphere developed.

Commentator: The expedition leader Markus Rex is now returning home will only come on board again in one of the later legs. He is handing over on site responsibility to his colleague Christian Haas.

Markus Rex: Now that the first phase of the expedition has been very successfully concluded, I can return home for a couple of weeks with a good conscience. I will fly back here to take over the leadership again at the beginning of April, possibly even the end of March. I will be with the ship till the end of June. Then I will have another four weeks at home and from the end of July until the end of October I will take over the reins here on board again. In the various periods in between I have appointed very experienced colleagues as expedition leaders and I have great confidence that they will direct the operations here extremely well and competently, so that the expedition will be able to carry on making measurements continuously throughout the year in a uniform manner without any interruptions.

In the next instalment of “Arctic Drift” the new on-site expedition leader Christian Haas will tell us about his impressions and current events in the arctic.

Arctic Drift - the Audio logbook.
Title: Re: MOSAiC news - inside impressions from first leg returnees
Post by: psymmo7 on January 12, 2020, 08:39:30 PM
Some insider impressions here:
Title: Re: MOSAiC news
Post by: binntho on January 13, 2020, 07:52:49 AM
Scientific American with an article (, not all that informative.
Title: Re: MOSAiC news
Post by: A-Team on January 13, 2020, 10:55:58 AM
Mosaic released a helpful observational ice thickness/ice surface elevation map in the context of describing a temporary landing strip on the port side. The ice proved thick enough to support the tracked Piston Bully needed to plow it. A longer strip that the Polar-5,6 planes can actually land on will be made in mid-February.

The ice thickness is measured by a towed electromagnetic induction sensor (of salinity); the surface elevation by lidar (called ALS for airborne laser scanner). The thickness was about 1.25 m, what they had expected at the time of the Oct 4th mooring. This is also very close to inferences in posts above based on cryo2smos weekly ice thickness reports (from calibrated satellite freeboard and dielectric).

Note that pressure ridge jumbles are considerably thicker (whiter) but they lack mechanical strength, contain considerable air, and melt very differently from true multi-year ice, a perennial misunderstanding on the melt season and piomas forums.

Once again, the bluish DEM depicting ice heights does not come with a scale. This is unfortunate because it would help with interpretation of oblique bow ice radar. Thin white lines indicate lat lon but they were not labelled! However these are probably 87.0º and 114.º given the date (which itself is uncertain but probably January 6th or somewhat earlier).

The overlay shows bow ice radar of the same date out to 2.5 km (dotted circle). Because of possible rfi (radio frequency interference) and separate dedicated instrumental coverage of the selected floe in the deployment area, the bow radar omits about 80 degrees of its normal coverage. A similar radar on N-ICE2015 provided full 360º coverage.

Mosaic released a second interesting image obtained by TLS (terrestrial laser scanning) which is lidar from elevated ground stations (a 3m tripod mounted on pressure ridges). An area of approximately 1 sq km can be mapped repeatedly with highly accurate ranges, heights and geo-referencing.

Areas behind objects are concealed from the light beam, casting shadows. Once the model is built from combined scans, it can be rotated interactively in open source software within a web page. Only a still is provided here. It's not clear how much of the area covered by bow radar has been imaged with TLS.

The moon has some unfamiliar attributes at very high latitude: it is bright enough under clear skies to read a newspaper and see colors, reflecting well off snow and ice and not setting for two weeks out of each month. The bright moon-lit scene provided on Jan 10th supplements the TLS and contradicts the long-playing sob story of researchers working for months in total darkness.

The ship's directional searchlights can illuminate a broad scene continuously but how far depends on their angle and objects in the way. Regardless, no searchlight or moonlight photos of the bow radar region have been released. With some control points out on the ice, the changing heights of the web of pressure ridges could have been estimated. However this is better done quantitatively from helicopter lidar and em bird as in the first image below.

The growth of the web of pressure ridges between Nov 1st and Jan 9th is shown in #488 above and and 2x enlargement below. How much of daily and special ice motion events was supplementally documented by ALS, TLS or ordinary photography is not known.

Mid-winter on the ice creates special safety issues (ie medevac for serious accidents and health problems) and logistical problems concerning fuel, food, and personnel exchange. These are at their worst in late winter when the ice is expected to be too thick for icebreaker access

leg 2/3 mid-February 2020, commercial Russian icebreaker Admiral Makarov arrives
leg 3/4 mid-April 2020, airplane personnel exchange, no fuel or food delivered: ice too thick
leg 4/5 mid-June 2020, research icebreaker Oden from Sweden arrives
leg 5/6 mid-August 2020, research icebreaker Xuelong II from China arrives

The expedition started on September 20th 2019 in Tromsø; it will finish on October 14th 2020 in Bremerhaven. Allowing two weeks for transits, this results in a full year of experimental coverage (though not exactly of the 'same' floe as it is ever-changing due to months already of almost daily ice rearrangements.)
Title: Re: MOSAiC news
Post by: A-Team on January 13, 2020, 05:32:12 PM
Polarstern Update:

-+- The easiest way to follow the incredible effects of a prolonged sub-gale force tailwind on Polarstern drift — westward at almost a tenth of a degree of longitude per hour and a tenth of latitude per day — is to simply scan the hourly online MET columns.

Wind in the 8-12 m/s range with 80º-100º bearing will push the ship towards the FJL-Svalbard gap. But this weather is moderating and perhaps reversing towards the end of the forecast period. The Polarstern has not seen storms coming up from the North Atlantic unlike N-ICE2015 which was beset by them from January on.

Then, by using MET's latest lat lon figures and UTC hour, initialize GFS nullschool, and follow its forecast out a few days with ‘shift-k’. GFS has been surprisingly accurate this fall and winter even though it does not appear to have ingested nor assimilated in situ buoy and ship weather data.

GFS gives an immediate picture — and explanation — of the latest Polarstern drift and a prediction of Polarstern position five days out. 'Passing lows' have limited explanatory powers. There haven't been any of note --  the lowest hPa since September 20th was an unremarkable 992.6 on Nov 16th. (The GAC cyclone bottomed out at 962 hPa with peak sustained winds of 130 km/h.) Drift is determined by near-surface winds, ice sails and edges, and resistance from keels. The current run has to do with strong southern winds off Siberia, not cyclonic lows. (loads nullschool at 87.3 106.7 on 20-01-13 at 15:00)

-+- Hourly MET reporting from the ship to ECMWF has not improved as eight gaps occurred in the last week, most recently 20-01-12 01:00.  Sometimes gaps can be repaired from sailwx. The problem is not plausibly in collection (sensors down) but with failed transmission (ie no redial).

-+- Bow radar coverage resumed out to midnight on Jan 12th but with 10 gaps in the 6-hourly coverage and only 4 new images and no infill of earlier gaps. Significant new ice shearing can be seen on the central-starboard side. Wind speeds have been fairly high but steady with no noticeable gradient or curvature.

Perhaps certain ship operations are incapable with ice motionimage capture and the associated radar operations have higher priority. It is certainly not storage — a single consumer-grade 256 GB SSD card could capture an entire year of images at one minute intervals. Transmission ashore cannot be an issue either given the pipeline. The Polarstern is not actually capturing that much data — all of leg1 fits on a single 20 TB external drive. Samsung sells a 768 TB rack of SSDs, enough for a half dozen Mosaic expeditions.

The first compound mp4 shows ice motion that preceded the remarkable double retrace that Uniq documented with three close-in buoys in post #481 above. The dramatic buoy drift reversals surprisingly did not have much effect on ice deformation in front of the bow. Instead a major ice movement cycle occurred a few days earlier as the buoys and Polarstern were drifted smoothly along. This suggests that the causes of ice motion are complex, not entirely local and possibly regional (or even basin-wide) meaning knowledge of the near-ship stress field will prove insufficient.

This early January sequence of events makes for an interesting case study of shear sliding and sticking. The lower section C is largely stationary; the upper section A is quite active. The B-B’ unit initially moves back and forth between A and C but later B’ gets stuck on A. As A-B’ move rapidly to the left, B’ slams into its former partner B and deforms.

-+- S1AB radar coverage resumed on 13 Jan 2020 at 03:35 after missing Jan 8, 9 10, and 12 (making those dates very unfavorable for joint coverage of ice motion). This is the 189th image in the 84 days since mooring. The Polarstern is currently not far enough north at 87.3º to be in the pole hole of Sentinel satellites at 87.8º which is ~60 km closer to the pole.

The exit track of the Kapitan Dranitsyn is still highly visible. It arrived on Dec 12th and left the 17th at 14:30 ship time  which is 12:30 CET which is 11:30 UTC [not making this up]. The KD possibly returned in part via the same lead it created coming in.

At prevailing temperatures, the entrance lead would have refrozen over the five day stay at the Polarstern but the return trip might have damaged the newly formed ice. The KD's beam is 27 m wide. Pack ice compression episodes should have closed the lead by now leaving a pressure ridge composed of re-jumbled new ice.

This unusual sequence of events has left a white scar on Sentinel-1AB radar that represents strong radar reflection from rough-textured ice (Mie rather than Rayleigh elastic scattering). The line can serve as a detector of shear and rotation at a regional scale far from the Polarstern. This can be seen already in the Jan 1st to Jan 13th comparison below: an left-center offset is visible.
Title: Re: MOSAiC news
Post by: uniquorn on January 14, 2020, 02:07:09 PM
drift update jan6-14, less meandering. S1B from jan13.
drift speed was incorrect on #481 edit: checked again, is good
Title: Re: MOSAiC news
Post by: A-Team on January 15, 2020, 12:46:41 PM
drift update jan6-14, less meandering. S1B from jan13.
Looking at sailwx, the GFS wind forecast driving Polarstern drift, the pole hole beyond 87.54º associated with Sentinel's orbit and swath, and the competition for its operating mode, it is safe to say we can say goodbye to open source satellite coverage for the foreseeable future.

The collection of 191 image links and precision Polarstern locations for the expedition to date are attached as a csv. The records also direct to the GFS of that date at the appropriate lat lon.

The ship's radar has also fizzled out again. While restricted to an area of ~20 sq km of a 7.1 million sq km  Arctic Ocean, it provides by far the best picture of local ice motion. The quality seems worse than similar radar on the RV Lance and some of the processing steps here are ill-advised.

It's not clear what is causing the erratic stop-start coverage. It's at the point of ruining the scientific value. This was not some impulsive impromptu hack of navigation radar ... capture is explicitly discussed in the pre-trip planning document:
In addition to the installations in laboratories in the ship, different kinds of instrumentation are installed at suitable positions outside on deck and along the railing of Polarstern. Most
prominent are opportunities to use the P-deck (observational deck) and the crow’s nest for
installations that require a view of the sky or access to higher altitudes:
• Radar for sea ice movement and deformation...

The scenes intrinsically blur and darken in proportion to their distance from the rotating mast radar beam. The former can't really be fixed by unsharp mask and the like. However contrast in the over-exposed bow area and under-exposed periphery can be evened out. Usually a radial transparency mask would be used. However it's easier and works about as well to apply a bimodal contrast LUT followed by mild adaptive contrast even though that doesn't act radially. The initial underlying image is unfortunately zoned, the scale bar off-center, blacks not black and so on. The goal here is to retain image quality after a 2x enlargement and improve clarity farther out from the bow.
Title: Re: MOSAiC news
Post by: A-Team on January 15, 2020, 07:05:24 PM
Meereisportal posted another drift segment colored by velocity using software not up to the task: there is no indication of time or dates and dithered colors are uninterpretable (ie do not correspond to anything in the palette).

The color jumble may be due to using one-minute GPS time resolution which is much more than can be displayed. They may have fitted a rolling 4-point cubic curve or spline and then colored continuously, with the jumble resulting from downscaling compression.

Why not just use GoogEarth where color and segments can be controlled without code and the data is shareable as kmz? Or Uniq's animation which is a lot livelier and carries the essential data within its frames?

The main use of one-minute GPS time would be determination of fine-scale acceleration (slope of the velocity curve). The icepack's inclination is always to decelerate because of frictional drag of ice keels with seawater underneath. This resistance goes up like the cube so whatever the wind, the icepack will top out at a very low terminal velocity, perhaps ~1.5 km/hr.

Since Mosaic measures the near-surface wind at co-temporal intervals, that could have displayed on the same graph, not as separately but integrally as a height. We cannot fix the graphic because Mosaic doesn't share either parameter at the resolution at which they are measured, ie the sailwx wind is an hourly average.

Ship drift velocity cannot respond instantly to an applied force but only with a lag as the icepack gets up to speed. Wind direction is an additional complexity factor. It's been steady since 01:00 on 20-01-09 which presents a great opportunity to isolate variables. Is the drift independent of wind direction or do issues like immovable land boundaries along the CAA give rise to anisotropy?

In terms of scientific co-visualization, ship and wind bearing need to be displayed cyclically. That is, 360º and 0º are the same, not opposite extremes as on the MET graph. That suggest a color wheel ROYGBV where red and violet are perceptually equated, the wheel being displayed as a linear background gradient along the time axis. The more common wind rose display has lost track of its time coordinate. However looking down the time axis, the bearing could be displayed as angle, wind as length and velocity as color.

Despite the coming unavailability of high resolution lat lon from Sentinel, the three close-in P-buoys provide the Polarstern's location as shown in the base frame below. Assuming the geometric relations between the ship and buoys are constant, it's still tricky to extract future lat lon numbers for the PS. Graphically, circles of fixed radius from P201, P204 and P207 intersect at the PS.

The mp4 shows that the mad dash west and north will morph into a strong move back east and south on the outer highly curved edge of a moderate cyclone.

The overall ice drift on the Eurasian side has been indecisive this year; Fram export has been good but is originating on the eastern Canadian side of the icepack. The Kara Sea is injecting its ice north of the FJL-Svalbard line again but not as much as a year ago.
Title: Re: MOSAiC news
Post by: uniquorn on January 15, 2020, 10:07:34 PM
Drift of 1.4km/h seems high at ~87.3N. The highest I could find from nearest buoys reporting drift speed (in m/s) are below. edit: 0.212*3.6 is only 0.76km/h

P201   2020-01-13T10:30:25,87.2753,107.3853,0.211
P204   2020-01-13T10:30:25,87.2957,106.7855,0.211
P207   2020-01-13T09:30:27,87.3551,106.6847,0.212

buoy data here (

Highest P204   2019-11-17T23:30:26,85.8660,121.2518,0.424m/s    1.53km/h

Something for spreadsheet analysts perhaps.
Title: Re: MOSAiC news
Post by: A-Team on January 16, 2020, 01:31:38 PM
Not understanding what is meant by "*3.6 is only 0.76km/h". Otherwise seems like either the buoys are not reporting in m/s as we thought (knots?) or the scale on the Mosaic map was miscalculated or it's in different units than labelled.

Meanwhile, the Polarstern is out of S1AB range. Mosaic also has access to various quasi proprietary radar data but those satellites too would be in near-polar orbit and not necessarily have a smaller pole hole than Sentinel.

Bow radar is not reporting either. The Polarstern has been in double digit m/s winds for 31 hours now which may be causing a lot of disruptive ice motion and downtime for deployed equipment. That could be the reason for non-reporting; "Follow Mosaic" is posting silly nonsense too.

Highest P204   2019-Nov-18 85.86  121.25   0.424m/s  1.53km/h

That date had high winds but not much bow radar ice motion. However the passing cyclone picked up again on 2019-Nov-21 causing the worst icepack disruption of the trip, gif below. Sailwx reported mild winds over this time frame; P204 etc were moving quite slowly according to the m/s column in 2019P204_300234068916790_proc.csv

The explanation is at GFS-nullschool: the ice was being 'drawn and quartered' at the Polarstern's location.
Title: Re: MOSAiC news
Post by: uniquorn on January 16, 2020, 03:56:32 PM
Not understanding what is meant by "*3.6 is only 0.76km/h". Otherwise seems like either the buoys are not reporting in m/s as we thought (knots?) or the scale on the Mosaic map was miscalculated or it's in different units than labelled.
Apologies for being lazy:  0.212*3.6 is only 0.76km/h  (edited previous post)

I checked the buoy data. Drift is in m/s
From P207

> distHaversine(c(103.3687,87.4686),c(103.3356,87.4702)) = 241.2289m  (lon first)
divided by 1799 secs = 0.13409m/s

close enough for me.
No data for our favourite Pbuoys today so far so I have added T56 and T62 to show drift. edit:updated below
ani data attached as txt
Title: Re: MOSAiC news
Post by: A-Team on January 17, 2020, 12:55:27 PM
Winds are a-changing and the Polarstern is heading back south and shortly to the east, where GFS has it caught in another 'drawn and quartered' stress situation very similar to the 21 Nov 2019 pattern above.

The bow radar archive is not currently updating. The ship will remain outside of radar satellite range though conditions can still be monitored by wide-swath/low resolution tools such as Ascat and proxies such as the three close-in P-buoys.

The persistent wind off Siberia that has brought the frozen-in Polarstern so far west and north towards the Svalbard-FJL also strongly affected the icepack in that area. Despite appearances on AMSR2 and Smos-Smap, this has nothing to do with intrusion of Atlantic Water, delayed freezing, early melt, or thinning ice (though those are all important in their own right).

Instead, the massive rifting of wind-blown ice is caused by export into the Barents. Watch the Svalbard island (Kvitøya) marked with the rectangular black dot. A large piece of light-colored ice can be seen swinging around into the Barents. Kara Sea ice is also moving chaotically but not systemically intruding into the Arctic Basin. There is also substantial advection of ice Fram-ward.

The slipstream (wake) of ice moving past small islands is very distinctive and can be tracked for many months in some years. It is a different type of feature than a buoy or virtual buoy in that it has linear extent similar to this year's clear boundary between FYI and MYI on Ascat.

Since the buoys are more or less drifting in tandem with each other and the Polarstern, it suffices to look at a single close-in buoy such as P204. Despite some glitches, its database has excellent quality with over 4600 half-hourly reads of position. The basic statistics are shown in the graph below.

A lot more could be done such as acceleration, correlations with latitude and longitude, and the relationship with hourly sailwx wind speed and bearing.

It is also easy to make a Google Earth trace of the 4600 line segments hexadecimal-colored by speed bin (GE uses hexadecimal, with transparency controlled by the alpha channel AA in #AARRGGBB 0-255 hex). Maximal value (255 dec, FF hex) means fully opaque.. The underlying kml provides a small distributable, extendable and scalable text file. Even though it refers to a buoy rather than the ship, its very high positional and temporal accuracies allow it to track the Polarstern's drift very satisfactorily.
Title: Re: MOSAiC news
Post by: uniquorn on January 17, 2020, 05:20:01 PM
Eyeballing the drift chart it seems acceleration/deceleration is easing off as the ice gets thicker.
drift update with change in direction as noted above. Pbuoys are back but reporting later so the 2 Tbuoys stay in.
edit: updated below
Title: Re: MOSAiC news
Post by: A-Team on January 17, 2020, 05:48:36 PM
acceleration/deceleration is easing off as the ice gets thicker
Certainly plausible. Maybe one of the SIMBA buoys would provide an ice thickness track. Correlation isn't causation but it's a good start. More ambitiously, integrate bearing (wind direction) from sailwx: might be harder to go north because the pack is run up against Greenland.

Here is some machinery that plots the same track colored for either speed or acceleration. It could be animated, tediously. I haven't binned the speeds into colors yet, just changed every tenth one as a marker. Meant to do 24 hr intervals (48 lines of P204 data) but did 40 bins instead which gives 115 line segments. (Any interval can be set rapidly; it is just modular arithmetic + sort on the count field).

This just uses lon lat sandwiched in between default kml gibberish. A segment needs two consecutive lon lat (from adjacent rows) followed by 'fill down' in a spreadsheet. A flatfile database can't do this, that's the difference between db and ss.

Attached are the slightly dated P204 database to from 10 Oct 2019 to 15 Jan 2020, the spreadsheet column magic that makes it work and the concatenated source (kml is insensitive to carriage returns etc so it compacts well even before compression to kmz).

Update: bow radar just came in with 16 new frames (and 1 new gap) bringing the archive up to Jan 17th! There is a substantial new instance of a large plate sliding 110 m along a previously established (Jan 1st fracture, small slip Jan 6th) shear line on the port side without snapping back or a lead opening (frames 9-10, another possible consequence of thicker and mechanically stronger ice. There are various other motions that don't involve large displacements. Recommended: open the avi in ImageJ as it has very convenient subsetting and speed controls.;O=D
Title: Re: MOSAiC news
Post by: uniquorn on January 18, 2020, 05:44:12 PM
drift update, jan14-18, with a burst of speed heading away from the pole, perhaps due to less resistance. Will look at adding wind speed/direction to the plot.
updated below
Title: Re: MOSAiC news
Post by: A-Team on January 19, 2020, 05:28:11 PM
Bow radar is steadily updating now. The ice is still shifting around in fairly minor ways, first port and then starboard; it is hard to predict if any of these are disruptive to experimental setups. The ship is currently at 87.4 98.3 20-01-19 15:00 3 70 in calm air but in a saddle of ice being pulled this way that according to GFS may show up in dramatic ice radar tomorrow. It does not look like S1AB coverage will resume next week.

The provisional bow radar availability mage is generated by the code below, concatenated over all 00:00 UTC locations from 27 Oct to 19 Jan. It displays the gaps in ice radar archive (red) with lat lon as provided by drifter P204. The ice radar archive does not cover October (4 blue days).

As Uniq notes, all the nrt databases are raw nuisances in terms of missing and glitchy entries, so integrating two of them involves a fair amount of editing of spreadsheets, grepping text and coddling of GEP kml.

Next up: integration with the velocity and acceleration proxy Polarstern track databases for an all in one extendable GIS-interactive scalable rotatable display with optional quantitative coupled data capture. It is easy to spoof lat lon slightly so different data types lie side by side.
Very people on the forums download or use free and easy double-click viewing tools such as ImageJ, Gimp, QuickTime or Google Earth which limits effectiveness given forum limitations.

A row of the bow radar database and its sandwich code looks like this:

296   263   12  Jan 2020   00:00   00   missing   44   -   ffd53e4f   12 Jan 2020   109.8739   87.2192   0.138   "<Style id=""sn_ylw-pushpin""><LineStyle><color>"   ffd53e4f   "</color><width>4</width></LineStyle></Style><StyleMap id=""msn_ylw-pushpin""><Pair><key>normal</key><styleUrl>#sn_ylw-pushpin</styleUrl></Pair>"   <Pair><key>highlight</key><styleUrl>#sh_ylw-pushpin</styleUrl></Pair></StyleMap>   <Placemark><styleUrl>#msn_ylw-pushpin</styleUrl><LineString><coordinates>   109.8739   ,   87.2192   ,0    111.464   ,   87.1618   ,0    </coordinates></LineString></Placemark>

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="" xmlns:gx="" xmlns:kml="" xmlns:atom="">
   <name>Polarstern bow ice radar.kml</name>
Title: Re: MOSAiC news
Post by: uniquorn on January 19, 2020, 07:45:06 PM
drift update. Another handbrake turn.
12 fps
edit: updated below
Title: Re: MOSAiC news
Post by: A-Team on January 20, 2020, 01:51:29 PM
handbrake turn
And that's with 30-minute frames. Would there be even more swerves on the 10-minute buoys?

The wind field out there has had a quite unusual configuration and it's about to get weirder in the next hours if GFS 3-hourly can be believed. The final frame on the animation is an hour later than the link below; the second frame of the slide show is 24 hours later,92.69,3000/loc=97.400,87.400

Meanwhile action has picked up on the Polarstern bow radar, with a new feature appearing in the last 12 hours on the port side but a couple km from the ship (far right). Quite a few missing scenes were patched yesterday to the point 2020 now has a complete 6-hourly record. October is still missing entirely; the ice may have been too flat then to give a good radar reflection. Again, it was not a good idea to conflate bearing with the ship-axial coordinate system.

The imagery can be improved quite a bit by fitting a cubic LUT to the initial contrast that brightens the dark edges and darkens the bow brights, then applying adaptive contrast followed by slight unsharp mask. This evens out the overall contrast, improves it locally and takes off some of the blur from the return signal that broadens with reflector distance. The negative sometimes provides more clarity and it's easy to pair both (2x enlargement below).

The Polarstern was within lat lon range of both Sentinel A and B this morning but no shots were taken for unknown reasons. If Mosaic has ordered up radar from other satellites, they're not sharing it. The last available S1AB scene dates to 05:54 on Jan 14th; the ship will soon be drifting deeper into the pole hole.

'Follow Mosaic' on Jan 18th reports on multi-faceted studies of a pressure ridge (Fort Ridge) whose location is not disclosed. It is up to 7m thick in places. Note this has to be measured directly rather than inferred from freeboard because voids affect density and ice may be held up locally rather than be at buoyancy equilibrium. The ROV has not yet imaged the keel from below.

Seasonal evolution of ridges is quite complex. Four were studied for six months during N-ICE2015 but even then the question remains of how representative they are of the whole Arctic basin:
Title: Re: MOSAiC news
Post by: uniquorn on January 20, 2020, 02:54:37 PM
Drifting gently northwest.
Forgot about the 10min buoys. 2019O1 temperature chart. cffr. A couple of interesting moments there.
Comparison of the 5 Obuoys with P204
Title: Re: MOSAiC news
Post by: uniquorn on January 20, 2020, 04:40:55 PM
Close up on 2019O4 ctr
Added overview of temperature at 100m and whoi itp102 profile contours. cffr
Title: Re: MOSAiC news
Post by: A-Team on January 20, 2020, 05:18:28 PM
This is getting interesting. We may be getting to the bottom of the barrel in terms of resolution though if the Polarstern is actually recording 1-minute GPS, they could be seeing yet more squiggles, ie icepack motion may be ~fractal. Some of these buoys can be reprogrammed from afar to take more frequent GPS though few would consider it because of battery life and iridium expense.

Below is a provisional (or slightly less) run at displaying acceleration. With speed, we are actually displaying velocity with color + track because the direction part comes for free as tangent to the track.

There didn't seem to be enough decimals in the 30-min velocities to difference them meaningfully to 30 minute accelerations. It seemed better to averaged over 30*8 = 4 hours or more before  differencing, coloring by bin, and displaying using first lat lons (because average lat lon won’t lie on the actual track).

Somewhere along the line my P204 spreadsheet got behind the times and very confused so this will take a restart with a fresh download and rethink of the vector direction aspect (same direction as applied force so would give the latter, so in effect fitting circle at each point along the velocity track). This is an easy spreadsheet calculation from rolling triples of points and Menger curvature (see wiki) though it requires a prior haversine of points n-1 and n+1 distance.
Title: Re: MOSAiC news
Post by: uniquorn on January 21, 2020, 02:50:46 PM
A closer look at the dip in ocean temperatures on jan2-3. Any ideas?
edit: added salinity
edit2: Got a surprise when looking at T68 temperatures ( at 2cm intervals. Will have to thin them out a bit.
Tech note: the first two or three lines are temps at the bottom of the ice
also added O and T relative buoy positions.
Title: Re: MOSAiC news
Post by: A-Team on January 21, 2020, 05:15:49 PM
dip in ocean temperatures on jan2-3?
It seems internally supported so not plausibly an instrument artifact. 'Follow' said at one point that the returning Atlantic Water core was still at ~300m and that would be warmer, not colder. Wind mixed layer out here in the middle of nowhere (86.8 117.0) in 4000 m deep water that was largely ice covered even in mid-summer? Neither tidal mixing nor tidal currents have any applicability at this location.

What are nearby CTD buoys saying about salinity on those dates and how broad an area can be shown to be affected by O-buoys? Double diffusion staircases are mostly across the Lomonosov ridge in the Makarov and Canadian basins with only one known in the Amundsen Basin. How about a turbulent diffusive convective eddy with a thermohaline finger intrusion providing layer mixing?

Meanwhile, back at near-term Polarstern drift, GFS shows a moderate persistent anti-cyclone bouncing around the basin with the ship assuming various orientations wrt its circulation. This pattern is fairly typical for the current strongly positive NAO (which however is predicted to dissipate by the end of the month).

Recent repairs to the Polarstern's bow radar archive have greatly improved the scientific value of 4x-daily coverage. There is still hope that the 22 remaining gaps will be filled; the 8 off-hour oddities will probably not be fixed, nor will any of October be furnished.

Hardly a day goes by without multiple areas of ice showing significant slippage. The last 36 hours though have not been notably disruptive near the ship. The problem is scaling out the bow region (including ice camp which is studied separately) to a broader view of icepack motion: is the observed ice motion regionally representative? The ship is currently located in the pole hole of all high resolution radar satellites so little information is available.

Looking at the thick colors in uniq's 2nd image in #510 (ºC @ 100m), it seems that the set of buoys provide a very convenient set of 'parallel' tracks that can be used to simultaneously display all manner of data. That is, a buoy's lat lon time can be spoofed with anything from weather to gaps in S1AB to peak ice motion to acceleration to some aspect of its own measurements such as ice thickness or salinity at depth.

It is quite feasible to have a dozen of these 'final frames' parallel the plain vanilla velocity track of the Polarstern. Alternatively, the data can be displayed, at least with GE, as a stack of bar graphs by increasing line width along the equator (by setting lat to 0).
Title: Re: MOSAiC news
Post by: RoxTheGeologist on January 21, 2020, 06:51:55 PM
Close up on 2019O4 ctr
Added overview of temperature at 100m and whoi itp102 profile contours. cffr

Why is the salinity decreasing with time? The thickness of the low salinity layer is increasing - I'm going to assume that the ice is thickening and expelling brine so I'd expect the salinity of the water below the ice to increase. Am I missing something obvious? Does it take all year for freshwater input from the rivers to reach equilibrium under the ice?
Title: Re: MOSAiC news
Post by: uniquorn on January 21, 2020, 10:20:39 PM
Maybe more influence from itp102/mosaic being close to the interface of two very different salinities (according to the model)
Title: Re: MOSAiC news
Post by: johnm33 on January 21, 2020, 10:39:00 PM
"Any Ideas?" Powerful low on 1st 963 twixt FJL/NZ would have 'called' for water from all quarters, did PS shift?, the high over the Canadian basin side would have 'pressed' some less saline cooler water over Lomonosov, near to but not at the surface, the coarse ice underside creating a stable zone with a sheer close below, may also have halted flow at depth down St. Anna trough?
Title: Re: MOSAiC news
Post by: uniquorn on January 22, 2020, 12:23:46 AM
Thanks for the ideas. I have a lot of reading/checking to do.
Posting these Obuoy temperature ani's for reference, 10-75m
Tech note: scales are different
Title: Re: MOSAiC news
Post by: A-Team on January 22, 2020, 01:21:45 PM
Obuoy temperature ani's for reference, 10-75m
Tech note: scales are different
The buoy sets are slightly different too? It looks like as many as 3 could be run without entanglement. The animation of the final frames and side-by-side are shown below.

Looking at 'Mosaic_multisensor' to see if the Mosaic expedition had access to other radar satellites in addition to what PolarView shows for Sentinel, it appears the answer is no. M_m is still poorly done with no mid-course improvements, with satellite images lacking critical access numbers, provided dates erroneous, 48 hour applicability falsely claimed, too small choice of scale, gratuitous rotations that make comparison of successive images difficult, lat/lon of position not synched with  S1AB and obliteration of the Polarstern region with the red circle. However a precise lat/lon for 0600Z can be read off the images on days no S1AB was taken. A poorly implemented scientific product inevitably raises questions about the rest.

The Polarstern is currently drifting west and more south 'on top' of a meandering anti-cyclone. Actual drift is generally 'to the right' of near-surface wind direction. Accurate latitudes are not disclosed so sailwx will sit at "87.5" even as it declines; longitude is decreasing by 1º per 22 hrs. The inset shows "87.4" is due at about 1800Z (except that wind direction and speed vary by the hour).

Very minor shearing is showing on the most recent day of bow radar. 'Follow' offered a possible explanation yesterday for varying image exposure and orientation: the radar is not gimbaled and so changes its incident angle if the stern swings around or the bow rises/falls (as ice anchors fail). This data could be used to uniformize the imagery but it is not disclosed, The PS also has strain gauges welded along its hull. That data is not disclosed either.

'Despite being solidly frozen into the ice, the forces of wind and currents* affect the ship. Depending on their directions, the Polarstern is pushed against the MOSAIC floe or pulled away from it. The latter strains the six ice anchors, which therefore need to be need to be monitored regularly. Today's check showed that five anchors were properly fixed - however one needed some additional care: Steffen and Andreas found a gap next to the 1.20 meters long metal I-beam. They filled it up with snow and poured water inside. The mix freezes solid almost immediately at the current temperatures of -28 °C.'

* No significant independent near-surface currents are known under ice in the central Arctic Ocean. A paper from N-ICE2015 describes the acoustic doppler measurement process and results; the four floes were located near the tip of the Yermak Plateau, meaning measured small currents were affected by tides, rising Atlantic Water boundary currents, adjacent ice edge, and passing storms; thus it is inapplicable to the Polarstern's situation. see 2.2.5, 3.5 and Fig 10
Title: Re: MOSAiC news
Post by: uniquorn on January 22, 2020, 03:55:30 PM
The buoy sets are slightly different too?
Thanks for checking. Just can't get the staff these days ;)
O6 75m NANs
O5 20m 75m NANs
O4 75m NANs
O3 50m NANs
O1 ok
A handy line of macid's original code takes out spurious very high(or low) entries and NANs (not a number) which mess up the nice colours.
There are a few good entries interspersed with a lot of NANs. Maybe I can show only those. I'll play around with it (eventually)
Title: Re: MOSAiC news
Post by: A-Team on January 22, 2020, 05:40:58 PM
would check work can't get the staff these days ;)
Would not more wealth inequality be the answer? Indentured R experts might do staff work for peanuts.

Alternatively, a spreadsheet classifying column can finger NaN's as singletons, doubles, triples etc. Pull up each class in turn with a sort, paste in a weighted tuple averaging expression that brings in good date from adjacent rows, and re-sort to initial order. This will cause a re-calc that makes the NaN go away. That expression works equally on databases of buoys, satellite gaps, weather misses and so on.

Just posting a close-up of a sturdy ice anchor that worked its way loose on the Polarstern. There are six of these deployed in pairs. It's not clear whether the anchor is bow or stern (midship is unlikely) nor what happened to its mate. The key to having them work as matched pairs is nrt winching to take up slack without losing the grip on the bollard.

An earlier 'Follow Mosaic' said these were improvised back in October in the ship's machine shop after the ice was found to be too thin to really freeze into. The massive iron shackles and sheathed hawsers are things they would have lying about but six I-beams?

Those beams are now over a meter into solid ice yet somehow one worked its way forward without bending or pressure-ridging the ice forward, possibly compressing porosity channels left by brine exclusion. The I-beam is correctly oriented for optional strength under a unidirectional load.
Title: Re: MOSAiC news
Post by: uniquorn on January 22, 2020, 09:12:35 PM
The animation colours don't really display enough detail. The charts show a lot more variation. The cold, occasionally salty, fingers appear to be quite local. O6 really struggling. ctr
tech note: should have picked a later start date, unexpected autoshrink makes text barely legible
Title: Re: MOSAiC news
Post by: uniquorn on January 22, 2020, 10:23:12 PM
Temperature gradient through snow and ice from T56, T62 and T66. ctr
data2 (

Quick analysis of T62 on jan22
Therm1-40 above snow
Therm41-47 snow/ice
Therm48-111 ice
Therm111-> ocean see inset

Title: Re: MOSAiC news
Post by: A-Team on January 23, 2020, 04:16:03 PM
The Polarstern has drifted south, reaching 87.4 at 0600 on Jan 23rd a few hours later than estimated in #518. The ship is still 290 km from the North Pole; the closest approach being 267 km with no prospects for northward drift this GFS week. Indeed a cyclone is foreseen swinging the ship far to the east (undoing a lot of recent westward gains).

The Polarstern is currently 1168 km from the entrance to the Fram Strait at 80.0N 0.0E. It is outside the pole hole of S1AB but its specific coordinates have not been imaged in the last 30 days. The area farther east, off the New Siberian Islands, is hardly ever imaged.

The overall motion of the icepack over the last three weeks is better described as a 'Siberian Slam' against the CAA than TransPolar Drift. Note the boundary between FYI and MYI remains quite distinct and easy to track. Ice radar motion in front of the bow has been negligible the last few days.

FoMo had quite an interesting post yesterday that shows the ROV is back in action after multiple relocations. Its view of the ice underside is key to understanding keels and mapping their evolution over time (eg erosion). We have often wondered why buoys fail; the explanation here is mis-installation.

The Fortress area jumble was not a good choice for a buoy site, better would be an area of flat ice without keels. However those weren't easy to find in early October. Second, the drill hole should be protected with a temporary pvc pipe through which the thermistor ribbon is threaded to its correct location and then frozen in.

The ROV is quite a neat device. Let's hope they release some video rather than just the occasional still. The only previous release was an underwater view of the Polarstern's hull.
Title: Re: MOSAiC news
Post by: uniquorn on January 23, 2020, 07:47:43 PM
drift update - see below
Title: Re: MOSAiC news
Post by: psymmo7 on January 23, 2020, 08:12:54 PM
Here is an English translation of installment 10 of the MOSAIC podcast that is only available in German on the MOSAIC webpage. It was posted there last Wednesday (15. January) but mainly covers events from mid-December last year, namely the handover from leg1 to leg 2 seen through the eyes of the leg 2 leader Christian Haas.

Moderator: Audio Now    Arctic Drift – the audio logbook.

Christian Haas: Hallo, I’m  Christian Haas, I’m the project leader for leg 2. I’m not just a researcher, I’m also head of the Sea Ice section of the Alfred-Wegener Institute in Bremerhaven and I’m very happy to have been chosen to take on this task.

Moderator: The next part of the Mosaic Expedition is in full swing. In the meantime, Christian Haas has taken over Markus Rex’s post and is now the local expedition leader for the duration of the second leg. He and the other expedition participants were only able to reach the Ice Breaker Polarstern and relieve the crew of the first leg after  a long and difficult journey through the arctic.

Christian Haas: Yes, our journey began long before we reached the Polar Stern, in fact on the 27th November in Tromsö, where we went on board the Kapitän Dranitsyn.
There were about 60 scientists including the logistic teams and Polar Bear lookouts as well as about 40 of the Polar Stern’s crew, the sailors that look after us here on the Polarstern. We boarded on the 27th and sailed off immediately, but we  only sailed about 2 miles into the fjord before we had to drop anchor as the ship wasn’t fully prepared for the high seas: because of this we had to lash all the containers on deck and store all the other freight for the expedition either in the helicopter hanger or under the foredeck. Then, sadly, there was a very bad weather forecast that predicted a big storm would be blowing over the Barents sea that would make it too dangerous to sail. 10 metre waves were forecast and the ship is only built to withstand three or four metre waves. Therefore, we had to wait for 6 days in the fjord, off  Tromsö,  before we could start the trip. After that the voyage lasted 10 days, 2 days to traverse the Barents Sea, where the waves were moderate and  most of the passengers took it well. And then we went into the ice along its edge where we safe from the next storm that had already sprung up, causing waves on the open sea. Then we sailed north of Severny island [Ed.: The northernmost part of Nova Zemlya], an island that is part of the Siberian Arctic, and set our course North to get to the Polarstern and that took another 5 days.

Christian Haas: The voyage to the Polarstern was very, very  exciting and we all had great expectations of getting there as soon as possible. To begin with the journey through the ice was relatively rapid, but then from day to day it became slower and in the end we were travelling at an average speed of only 1 knot, so that the people on the Polarstern, who were greatly looking forward to finally being relieved, asked what we had been doing. But the Dranitsyn was just very cautious going through the ice to avoid getting stuck and  so took  her time to get to the Polarstern.

Moderator:  The new crew also had to get used to conditions in the arctic. The ice breaker supply ship Dranitsyn had to make its way in the darkness from waypoint to waypoint until it was only a few metres away from the Polarstern before materials and crew could be exchanged between the 2 ships.

Christian Haas:  The first interesting thing was that  on the first day of our voyage there was already no daylight, so that we had to get used the darkness. That made our first glimpse of the Polarstern in the distance, after 10 days at sea, all the more amazing and impressive. However, because it was roughly 40 miles distant, it quickly became clear to us that what we were seeing was a Fata Morgana, caused by reflections from air layers, which was itself an interesting phenomenon. Then we received a delegation from the Polarstern that came to us by helicopter from the Polarstern. One of the officers from the Polarstern, was seconded to us. He knew the waypoints and the coordinates and had an exact plan for how we could approach the Polarstern without colliding with any of the buoys which make up the network of autonomic stations around us that carry out automatic measurements. He knew a secure route for being able to get us as close as possible to the Polarstern. This was done very professionally and  in impressive style. The prow of the Dranitsyn approached the stern of the Polarstern to within 6 metres, so that nothing had to be offloaded onto the ice but instead, using the cranes of both ships,  it was possible to transfer freight and personnel between the two ships in both directions at the same time.


Christian Haas:  Despite the amazing positioning of the two ships it was unavoidable that we did have to transfer some heavy items from the stern of the Dranitsyn to the Polarstern via the ice.  This was done using 2 cranes in tandem, because items on the Dranitsyn couldn’t be transferred from the aft part of the ship to the front part. Instead, we had to offload heavy items such as helium gas cylinders onto the ice, then they were transported from the stern to the prow with a tracked vehicle and then they were taken up by the crane again to lift them onto the starboard side of the Polarstern. We were very happy, because the ice on the port side of both ships remained very stable, at least to begin with, but on the last day a crack in the ice did appear so that immediately after the last transfers had been completed it wouldn’t have been possible to traverse the crack and transfer the last heavy items from the helicopter deck to the Polarstern..

Moderator:  The expedition members could now make an on the spot appraisal of the situation and inspect the ice floe on which they would be spending the next months. For the first time they were able to see for themselves the cracks and other ice structures from which until then they had only heard from their colleagues and which had had such a strong influence on the expedition. 
Christian Haas:  We of the second leg were now very curious to have a look at the situation on the floe and see all the changes about which we had heard so much and from which leg 1 had had to suffer so much; in particular the cracks that were opening all the time and the displacements that occurred. And, as if pre-ordained, the next cracks appeared on the day of our arrival. One of our first actions was that we had to help out. Some of the instruments, especially the remote-controlled instruments, were standing on the ice in the covered area called  ROV City under which a huge crack had developed, directly under the covered area, and we had to rescue them. There was a lot of speculation about whether the cause might have been because the Dranitsyn had to come so near to the measurement area to access the Polarstern. But I think that it was in general caused by the high drift speed and the strong wind that prevailed at the time and that it was a simple deformation event, Anyway since then it’s been the case that the ice has been very, very quiet. Indeed, actually  that was the only deformation- or  break-up event that we ourselves experienced. Since then the floe has quietened down a lot. We moved the remote-controlled instruments and ROV city to a new site. But we haven’t had to reorganize anything else simply because the ice in the immediate vicinity and in the area where we are making measurements has remained static  and we have therefore been able to concentrate 100 percent on our projects and our measurements and have been able to work unhindered

Moderator: in the next installment you will find out how the new crew has adapted to life on the Polarstern and what progress the scientific measurements are making.

Moderato:  Arctic Drift – the audio logbook
Title: Re: MOSAiC news
Post by: uniquorn on January 24, 2020, 10:34:57 AM
drift update - see below
Title: Re: MOSAiC news
Post by: A-Team on January 24, 2020, 03:22:02 PM
Thx psymmo7, very helpful!
caused by the high drift speed and the strong wind that prevailed at the time and that it was a simple deformation event, Anyway since then it’s been the case that the ice has been very, very quiet. Indeed, actually  that was the only deformation- or  break-up event that we ourselves experienced. Since then the floe has quietened down a lot.
:) requires special skills in translation -- that's not at all what the ship radar shows at the time. Note the sheared ice ramming the port side of the Polarstern on Dec 18th as the Kap Dranitsyn was leaving.

Be sure to set the mp4 on loop to see the eyes, nose, jaws and hand of a feeding sea monster.

There are slow days to be sure but yesterday saw some unusual action when a large triangular piece at the 'bottom' pulled away slightly and then rejoined at a slight displacement. This is not likely to have had any effect on ice camp operations.

Note the oddity at the apex of the triangle: it appears as though a horizontal layer has slid off, exposing not water but, implausibly, a lower horizontal layer of ice. The event is not finished; we need a few frames from tomorrow. The frames are six hours apart; there is no intermediate information.

Looking back to Nov 1st, neither of the cracks making up the triangle sides has been active previously. This is mildly inconsistent with theories that most events represent re-activation of previous faults and weaknesses. Some are, but looking at the overall growth in the white lattice, new fracture lines are steadily accruing.

False claims of aurora discovery at FoMo are exceedingly >:( to scientists who actually work in magnetosphere physics. Given NOAA's 3-day forecast online animation, nullschool 'space' display, and wikipedia's treatment, it's hardly news that the aurora borealis is commonly visible at extreme northerly latitudes. That animation is worth a look for its advanced techniques:

If GFS is halfway accurate two days out, the Polarstern is about to encounter strong ccw winds at the top of a cyclone that will take the ship far to the east and south (ie wrong directions).
Title: Re: MOSAiC news
Post by: uniquorn on January 24, 2020, 10:16:58 PM
Further analysis of T62 showing temperatures since oct29. From left to right are surface temperatures, the temperature gradient through snow/ice then ocean temps which have been enlarged inset. Thickening ice clearly visible in 2cm steps per thermistor.
Lowest temps on dec27 were -37.75,-37.88,-37.94,-38.00,-38.00,-38.00,-38.00,-38.06(Therm34),-37.62
Title: Re: MOSAiC news
Post by: uniquorn on January 25, 2020, 10:50:56 AM
slow drift
edit:updated below
Title: Re: MOSAiC news
Post by: uniquorn on January 25, 2020, 01:05:21 PM
T59 may be a candidate for FoMo jan22 post. No change in the data after 2019-10-18T03:00:14
It may not be near enough to PS though.
edit: added T56 for reference, data is also very odd. edit2: that's because I processed the heat file. I've removed it till I find out what it is.
Title: Re: MOSAiC news
Post by: A-Team on January 25, 2020, 04:30:20 PM
Mosaic installed a secret array of close-in sensors that use the radio LAN and do not report through Iridium (ie don't show up at IABP or MeerEis). T59's thermistor may also have gone astray in a keel. This is a second type of type of buoy failure: still reporting but not informative, here constant near-surface seawater temperature.

IABP today shows 97 Mosaic buoys of which 19 are no longer reporting at all and an unknown number not reporting like T59. All 6 buoys put out in Dec-Jan 2019 by AWI from the Kapitan Dranitsyn have failed.
Yesterday, we recognized subtle deformations of the #ice floe in the vicinity of #Polarstern on the ship’s radar. A logistics team went out for scouting: a big lead 50 m wide by 1 km long had formed along a shear zone. A good chance to measure energy & gas fluxes! This was the long-awaited “event”: the chance to measure energy and gas fluxes between the water and air, through the newly formed and older ice. Additionally we carried out a special high resolution survey of the lead with the helicopter-borne laser scanner. It also allowed to study the initial population of the newly forming ice by ice-inhabiting biota.
That's it. FoMo doesn't provide any location data (starboard side? 200 m from bow?) nor mark up one of their own bow radar frames nor provide freeboard or the scan. (The scientists aboard do not write these blurbs -- AWI has a staff of 11 full-time publicists to do that.)

Based on 'subtle' and convenient access to the Polarstern, I re-examined the bow radar images from Jan 14th on at 2.5x enlargement. Sure enough, there is newly active minor lead abaft the port beam. The boxed feature in the mp4 has dimension 0.50 x 0.25 km. The original avi has 80 pixels for 1000m so a 50 m feature will only be 4 pixels wide.

It is not feasible to cover every scale from the hairline shear cracks that tipped over the Met tower to mega leads opening off Banks Island. Various papers have put forth power law fits to scaling but based on unsatisfactory coverage and detail of observational data.

Much more dramatic local ice dynamics is going on at the same time farther off the bow but getting there regularly would present time-consuming logistical problems over rough ice. Bear guards are always needed because cooking odors and curiosity are drawing them in from nearest natural prey sites 100's of km away, just like inland drill sites do in Greenland. 

The minor lead being studied will freeze over in a matter of days at -28ºC. However the real problem will coming from multiple rounds of closing and reopening which are already underway. The final state will be closed up the pressure ridge sense, not closed up as frozen open water. That's because compression events take up any slack during the freezing season: the vast majority of shear and lead events in ~3 months of bow radar have become inactive.

Overall, the ice is too weak and its motion too extreme to accomplish very much of what Mosaic set out to do. And it could get worse if some winter storms set in. GFS is sticking to its prediction of rapid drift towards Wrangel Island starting at 1800Z today. The next 24 hours of drift is suggested below. Winds will be picking up from 6 to 11 m/s.
Title: Re: MOSAiC news
Post by: uniquorn on January 25, 2020, 11:14:01 PM
T63 looks like a good buoy, probably deployed on thinner ice, growth is faster and the temperature gradient quite different for a while.
Title: Re: MOSAiC news
Post by: uniquorn on January 26, 2020, 01:24:17 PM
drift update
Title: Re: MOSAiC news
Post by: A-Team on January 26, 2020, 03:25:53 PM
The Polarstern got caught up in strong winds to the southeast at about 06:00 this morning as GFS foresaw a few days back. The winds are not quite gale force but will peak in the 10-12 m/s range and stay brisk for a couple of days.

Under these conditions, longitude will be gained at about a tenth of a degree per hour; in 3 days the ship could plausibly be at 87.2 100.0.

A very dramatic lead opened off the port side, preceded by a possibly enabling large scale shift two km off the bow. The event is still ongoing so we await the next day of bow radar (which unfortunately has become erratic again). In part, an old prominent slipline reopened, not entirely but with new leads taking off at the ends.

Looking at the regional wind stress picture over this time frame, it appears that the problem is not high wind speed per se at the ship but rather its rapid fall-off nearby, ie the stress gradient. How far out that matters is a big unknown, perhaps ice basinwide contiguously adjoined to the Polarstern floe (ie rigid body motion).

I added streaming awiMet ship weather to the ice radar since that wasn't happening at their end. It's a doable nuisance to go back to the Nov 1st start because of almost daily gaps in hourly awiMet weather and unsynchronized missing or unusual radar timestamps. There is enough black space to include a small thumbnail of GFS winds at each of the 320 bow radar frames to date. The  bow to stern length of the ship (9.4 pixels) could also be depicted.
Title: Re: MOSAiC news
Post by: uniquorn on January 26, 2020, 04:59:52 PM
Similar activity on a macro scale from rammb, jan22-26. The latitude line is unlabelled but sits between 85 and 90, so should be 9 87.5.
edited to attempt to get the centre closer to current mosaic location
Corrected: 97.5 off the planet ;)
Title: Re: MOSAiC news
Post by: uniquorn on January 26, 2020, 08:35:37 PM
Apologies to T56 which is in fine fettle. Probably enough from Tbuoys for now.
Title: Re: MOSAiC news
Post by: A-Team on January 26, 2020, 09:07:55 PM
so should be 97.5
so should be 87.5.

Same Rammb final frame as #535, corrected for this and that. The PS is slightly up and to the right of the red asterisk.
Title: Re: MOSAiC news
Post by: Jim Hunt on January 26, 2020, 09:09:12 PM
Growth is faster and the temperature gradient quite different for a while.

The gradient change (especially when the air is cold!) reveals the boundary between snow and ice.
Title: Re: MOSAiC news
Post by: A-Team on January 27, 2020, 01:32:17 PM
Major fracturing and re-association of seven active ice plates continued today as expected from winds in the 11-13 m/s range with a sharp NS gradient. The bow radar view of 280º degrees includes the port side but not the deployed equipment starboard area which may have been seriously disrupted as well.

Eight hours past the last frame, winds abruptly dropped to 4 m/s as the ship came off the shoulder of the cyclone at 10 am on Jan 27th at 87.4  95.8.

The wind gradient image shows stress on the ice moderate near the pole, increasing to a maximum near the Polarstern and very low an equal distance farther south but all in the same direction. This results in ice moving forward (east) at different speeds across the gradient. That is what is causing the plate commotion as rigid ice cannot move coherently at different speeds. High winds alone are necessary but insufficient for a steep gradient; in a more homogenous stress field the ice pack could simply translate (modulo boundary conditions).

The buoy tracks establish that OsiSaf, which requires two days of data averaging and re-gridding, cannot capture motion at the relevant temporal and spatial scales. While too few buoys are put out to accurately depict ice motion for the Arctic Ocean overall, the buoy array could be used to patch OsiSaf locally.

S1AB rarely covers this latitude. The Polarstern and surroundings have not been imaged since Jan 14th but the ship did show up on the edge of 06:36 image on Jan 27th. That will be nearly the exact time as the first image on bow radar avi tomorrow.

The bottom image shows the jp2 and jpg versions from PolarView. The spatial resolutions (25 pxl/km nominal) do not provide a wholly satisfactory continuation of bow radar scale (80 pxl/km). Very little lead or ridge detail matches. Both can have 3-4x daily coverage, though S1AB arrive in a morning burst and bow radar evenly at 6-hr intervals.
Title: Re: MOSAiC news
Post by: uniquorn on January 27, 2020, 02:01:38 PM
Recent drift mostly east, a touch north, at speed.
So T56 snow depth 10-15cm, similar to the images on FoMo.
updated below
Title: Re: MOSAiC news
Post by: psymmo7 on January 28, 2020, 01:53:03 AM
Here is an English Translation of a transcript of the latest Podcast from the MOSAIC Website that is only available in German.

The Podcast was posted last Wednesday (January 22)  at 5:57 PM on the MOSAIC Website (in German) - the recording itself was probably made 8. January

Instalment 11 – thick ice, four-legged visitors and slight frostbite

In the meantime, the team around the new leader of the MOSAIC-Expedition, Christian Haas, has accustomed itself to life on the ship and to the camp on the Ice Floe. In this instalment the Sea Ice physicist goes into detail about the composition of the ice and how it is continuously changing. Apart from this, Dr. Haas also reports on measurements made by other scientific disciplines and explains how an aircraft landing-strip is made on the ice. The continual decrease in temperatures and the ongoing polar night present further challenges for the members of the expedition. And, this week, the camp got another animal visit.

…..[Ed.: Just so that transcript readers don’t miss out on the atmosphere of the podcast they should know that it is preceded and ended by sound recordings of strong wind and creaking ice….]

Arctic Drift – The audio logbook.

Christian Haas:   At the moment we are at 87 degrees 8 minutes North. During the MOSAIC expedition the ship this the most Northerly that the ship has been. [Ed.: According to the positions reported on MOSAIC webpage this would date the time that this recoding was made a being around 8. January]

Commentator: In the meantime, the leg 2  Team has adapted to arctic conditions. The crew around the new  Expedition leader Christian Haas has familiarised itself  with the Icebreaker  Polarstern and the condition on the home floe. Dr. Haas himself is head of the Sea Ice Physics section of the  Alfred Wegener Institute and can precisely explain what an ice floe is and why the ice in the arctic is constantly changing.

Christian Haas: we are always using the term “ice floe”, but everyone probably imagines something different under this term…and at this time of year, in the middle of winter, there aren’t really any, anymore. When the  Polarstern arrived here at the beginning of October, it really was the case that there were individual ice floes drifting in the water. They were separated from each other by water or thin ice. But the ice and the ice floe formed a unit and could be regarded as a swimming platform.   The MOSAIC ice floe had a diameter on the order of two to three kilometres. But since we have been here and the winter has begun, the whole area around us has frozen solid, so that one can’t make out individual ice floes, because the borders between them are not visible, except with the help of Satellite data. Nonetheless it’s the case that the ice floe isn’t a plate, it isn’t a simple uniform plate of ice, but, as before, it regularly fractures and is displaced by shear zones. Till now we have just had a lot of luck that such shear zones and fractures didn’t go directly through our camp but were some distance away. Just yesterday we made an exploratory tour with snowmobiles to the West and East and at a distance of about two to three kilometres in each direction we found tears and shear zones.  With that we could say that the floe is  two to three kilometres in size, but the Northern and Southern boundaries haven’t been found yet. 

Commentator: The ice and the alterations in it are being constantly observed. Using different kinds of measurements it is possible to completely understand the displacement of the ice. Many researchers view these displacements as a danger, because they can lead to interruption in their research. Others welcome the possibility being able to  observe and analyse them directly. 

Christian Haas: The ship’s radar, that every 10 minutes makes an image of the surroundings within a radius of 5 kilometres, helps us a lot. When one looks at a time series of these images it’s like looking at a film of the ice movement. Most of the time the ice is stable, but sometimes one sees shear events, where, because of a difference in the extent of ice-drift in different regions, a part of the floe suddenly slides by between several metres up to as much as 100 metres relative to the other part. These zones produce tears and the formation new pack ice ridges.

Christian Haas: For most of our colleagues here the tears and the formation of pack ice ridges are seen as a hazard, because they interrupt research. But for us as researchers and  for the whole MOSAIC project of course it’s an important process that we want to investigate.  This is because we want to better understand why the ice in the arctic has declined so much during the last few decades and to find out what processes result in the ice becoming thicker or thinner. The growth of pack ice ridges, the deformation of the ice and the sliding of pieces of ice on top of each other  is a very important process and can make ice much thicker than it would become through solely as the result of freezing through contact with the cold atmosphere. For this reason the sea ice researchers and remote sensing experts who are involved in our project are very thrilled to be able to observe such deformation events at first hand and to be able to see how the ice can continuously become thicker through floes fracturing and sliding on top of each other. 

Commentator: In the meantime, the floe ice is circa one metre thick and has doubled in thickness since the beginning of the expedition in October.  In comparison, the so called “pack ice ridges” are considerably thicker. To investigate them more thoroughly various instruments have been installed in the ice.

Christian Haas: We see here that some pack ice ridges are up to three metres high. Pack ice ridges are like icebergs, that means that roughly a tenth of appears above the surface and nine-tenth of them are under water. It follows that where there are pack ice ridges the ice can be 10, 20 or even more metres thick. We have observed this with our remotely controlled ROV, with which we were able to make  sonar measurements of the ice depth and we have already found ice thickness of over 10 metres. In our last big action, we installed a number of instruments in some of these pack ice ridges. We call this the “Pack Ice Ridge Observatory” and we want to use it to observe on the one hand how the underside is eroded by currents and by the warmth that is present in the sea water and on the other hand  how the pack ice ridges are frozen from above. In addition, we want to know how, because of their rough surfaces, they are affected by turbulence in both air and water and whether this is important for their growth or melting.

Most ice measurements are made by drilling holes in the ice and then placing instruments underneath the ice or in it. That’s exactly what we have to do here. We have placed large measuring devices, that require large holes to be drilled, at the periphery of the pack ice ridges and underneath the ice. These are for instance instruments that measure water currents and turbulence.  Then we embedded thermistor chains over the whole ridge as well as in the thickest ice, that was more than 8 metres thick in places. With these chains we can observe how the ridges cool, how they freeze in the centre, and how the processes of erosion and disintegration  take place on their undersurface.

Commentator: Research in other scientific disciplines is also ongoing. A great deal of weather data is being collected both on the Polarstern and  in the Ice Camp. Still lower temperatures than the current low temperature of minus 35 degrees have been measured there and that has led to one or two expedition members experiencing mild frostbite.

Christian Haas:  By itself the air temperatures aren’t sufficient to judge how cold it really feels on the ice, because it’s the combination of air temperature and wind strength, what’s called “windchill”, or in other words perceived temperature,  that’s important. Unfortunately, some of the coldest periods occurred at the same time as phases when the winds were strongest. Windspeeds went up to 50 km per hour and the perceived temperature fell under minus forty-five, sometimes under minus fifty. This made work on the ice very, very  unpleasant and even almost dangerous. Although we have very good extreme weather clothing, a few people still managed to experience mild frostbite on their faces. This is very difficult to avoid when you are really concentrating on your work and you forget how cold your cheeks, or your nose, is getting.

Commentator: The safety of the team is still first priority. In case there should be a medical emergency, that luckily hasn’t happened yet and hopefully won’t in the future, then expedition members can be airlifted out. 

Christian Haas:  We are approximately 300 kilometres from the North Pole and therefore a long way from any form of human civilisation and from any form of help that we would need if an accident were to occur. Basically, we are further away from help and civilisation than one would be on the international space station.  For this reason, we have made contingency plans for how we would obtain help in case it was really needed. One of these plans is that we could be reached by a light aircraft with skis that could land here and bring help or airlift a sick person out.  However, such an aircraft would require that we have a more or less even landing strip, which wouldn’t be there naturally, because the ice needs to be thick enough - at least 50 centimetres – for the aircraft to land safely. Because of this, during the last few days we constructed a test landing strip close to the ship, so as to minimise our use of  resources. To do this we used Pistenbullys, these are tractors equipped with snow ploughs and rotary hoes [Ed. In English they are also known as “Snowgroomers”]. This Pistenbully prepared a roughly 400-metre-long, 25-metre-wide  landing strip, that is very, very flat – so flat that even an aircraft with landing wheels could land here. That was a very important exercise for us to allow us to  prepare for the construction a larger landing strip that we will need for the changeover between legs 3 and 4.

Commentator: The scheme for protection from Polar bears is also still active, although so far during leg 2 no polar bears have seen. Instead the camp was visited by other four-legged creatures who unfortunately caused minor problems with various measurements.

Christian Haas: The pin up animal for the arctic is the polar bear and we are prepared for them in all sorts of ways, although they aren’t as dangerous as they are often made out to be. But, to our great disappointment, we haven’t yet seen one. This isn’t perhaps so surprising, because in the middle of winter, when its dark and the ocean is almost completely frozen over, there are neither seals nor any other kind of food.  Then the polar bears tend to go South. Therefore, given that our tour of duty was the mid-winter one, perhaps we shouldn’t necessarily have expected to see many of them. But what then  did surprise us, although there are past reports of it, is that we were visited by Arctic foxes. Up to 6 of them were seen. They stayed in the neighbourhood of the ship quite a long time, circling the ship and playing. That was something of an occasion here and a bit of a diversion. Naturally, first of all we thought that the foxes were cute animals and nice to look at. However, actually they presented something of a danger to our measurements because they love chewing cables. And accordingly, some of the foxes chewed through some of the cables that we had laid across the ice to connect measuring instruments with dataloggers, batteries or generators, interrupting measurements. But then we were able to successfully protect the cables against the foxes and were able to drive them away and for the last two weeks there haven’t been any more foxes here and our work could continue unhindered.[Ed.: on the MOSAIC webpage on 6 January a further instance of damage was discovered and  reported and the remark made that the foxes had been seen at “the end of December”] 

Commentator: Christian Haas is looking forward to the coming weeks and the upcoming research work, although the conditions for it won’t be made easier by the continuing polar night and the further decrease in temperatures. He is very focussed on keeping the goal of the MOSAIC expedition in his sights.

Christian Haas:  We are still moving into February and March, that’s actually the coldest season in the arctic. That means that weather conditions will become even more extreme. Nonetheless, I believe we will continue to work enthusiastically on the ice. Because now, just as we are slowly beginning to get good time-series measurements of atmospheric conditions and of ice and water conditions, the information is becoming increasingly interesting and we are getting nearer to fulfilling the goal of the MOSAIC expedition to investigate the interaction between the atmosphere, ocean and  ice and, and we shouldn’t forget that, the Biology of the arctic. So I hope that we will continue to be able to work unhindered. Naturally one or two ice deformation events should also take place, if possible, at quite a distance from the  ship. We will continue to expand the radius of the area that we move in. Apart from that, I hope that we might indeed get a storm that will bring us some snow. Till now the snow has been very sparse, the snow cover is between eight and twenty centimetres. And what we also hope for, even if it may sound paradoxical, is that at some stage we get an intrusion of warm air that will temporarily give rise to very high temperatures and even to a little rain, as has been seen with increasing frequency in past years and about which there has been much speculation as to the effect it has on ice cover and ice growth. We now have a unique opportunity to observe the phenomena on the spot and that is absolutely necessary to better understand these processes. 

Title: Re: MOSAiC news
Post by: uniquorn on January 28, 2020, 11:22:49 AM
Drift update, testing the brakes before a hairpin bend. :updated below
Added a close up from 27th onwards of the nearest Obuoy (to the north east) which report location every 10 minutes. No drift speed but the ani has 6 frames/hr (at 7fps)
O4 temp/salinity/pressure chart from meereis. That still doesn't make sense to me, a sharp salinity increase but temperature goes down. (legend position is unfortunate, see #521)
edit:Looking more carefully, the spike in salinity is at 20m. At 100m salinity dips with the drop in temperature.
Title: Re: MOSAiC news
Post by: A-Team on January 28, 2020, 07:26:25 PM
Nice interview, psymmo7. Haas is not correct about ten minute intervals between bow radar scenes. For example, the Nov 11 has two scenes three minutes apart, 12:00 and 12:03.

This is important for determining operational safety. That is, can massive rifts open in seconds or is the time scale minutes, hours or days, conveniently preceded by ample warning noise? They have already had one scientist fall in up to her waist, another to the top of his boot.

On leg 1, they ran out of connectors and could not replace critical cabling buried under yet another overnight pressure ridge until the relief icebreaker arrived. Some of the cracks grew very slowly and could be monitored for days, like the one that eventually toppled and broke the Met tower.

FoMo posted a great graphic yesterday showing open water many meters wide associated with an overnight 5 m pressure ridge that buried their snowmobile track.

Looking through the totality of bow radar image pairs to date, the worst case scenario was the Jan 26th pair 09:57/11:59 (see above mp4), with massive km-scale leads and ridges forming within 2hrs 02min of separation. Quite a wide area was affected over days so it wouldn't take bad luck to be in the wrong spot at the wrong time.

In past years, we have seen cracks propagate from Banks Island to western Siberia overnight, minimally 40 km/hr. The Norwegian airboat camps were hit twice with serious loss of equipment.
Added a close up from 27th onwards of the nearest Obuoy (to the north east)
Here is the mega track of buoy 201904 back to Day One. The display is generated by the 16,142 points at 10-minute intervals. The attached kml file allows unlimited zoom, rotation, and co-display with other types of tracks such as S1AB availability, bow radar availability, wind direction from sailwx and so on.

The Polarstern's track would be virtually indistinguishable at this scale, with a constant offset from this buoy. The velocity of buoy 201904 is easily computed within its csv and assigned a color palette, as is any scalar quanity (such as salinity or temperature at a given depth) measured by the buoy.

The buoy overview graphic at Meereis Portal is done well; the palette allows selection of individual buoy types and color changes. There do not appear to be any 'snow buoys' or 'other' displayed. Again, this is best done in GoogEarthPro with a folder containing a folder of each buoys class because this allows disentangling the complexity via checkboxes and visitor download of the data generating the image.
testing the brakes before a hairpin bend
The proximity to the cyclone center could have unprecedented effects on ice disruption.
Title: Re: MOSAiC news
Post by: uniquorn on January 29, 2020, 12:25:02 PM
drift update, slow, headed northeast
~11days in 250frames @ 12fps
updated below
Title: Re: MOSAiC news
Post by: A-Team on January 29, 2020, 01:00:47 PM
Winds are moderate but shifting around quite a bit, with temperatures up 12 degrees from the expedition low of -35º on 20-01-28 (which fortunately had only 3 m/s wind chill). It doesn't seem like barometric pressure has settled into much of a winter pattern so far; this is resulting in a meagre Beaufort arm and back-and-forth in the Fram export area.

All three Ascats are back after several days of shaky downloads to the base stations. S1AB caught the ship on three recent days despite the extreme latitude. Mosaic_multisensor was discontinued on Jan 21st; it needs re-conceptualization.

Bow radar of the last 48 hours shows newly constituted ice plates settling back down after extensive regional shearing earlier. This relaxation process has repacked ice blocks more or less the way they were before. Floe boundaries formed during fall freeze-up have seemingly lost relevance even though the joints are commonly presumed weak and prone to fracture.

FoMo posted a very interesting photo on Jan 27th of a 5m high pressure debris and extensive open lead. The jumble of ice obliterated an Ice Camp road (snowmobile track). The lead has quite a bit of broken ice floating in the water, frozen in like raisins in pudding by now with the temperatures in the -30's.

What probably happened here is the lead opened and closed repeatedly, forcing ice fragments onto one shore. This does not make a proper pressure ridge, no keel. It is clear from the photo that snow accumulation has been minimal (below a boot) and the ice has not thickened much at this site.

FoMo's most recent post shows leg 3 participants loading up for the mid-February replacements and refurbishments. The relief icebreaker is not likely the Kapitan Dranitsyn as stated. The KD is not a proper icebreaker to begin with, cannot function in 3m waves when loaded with scientific containers. It got stuck already leaving in December ice.

The KD has no prospects of reaching the Polarstern nor returning to port in the thicker ice of mid-February. It's hugely expensive to be rescued by a commercial nuclear icebreaker and can involve several weeks of waiting at sea because of prior scheduling commitments. So this will be the Akademik Fedorov doing the exchange.

The 3rd image shows the level of buoy track detail available in GEPro (compare to #541 above). It is a fairly good match to the buoy's GPS accuracy at this latitude.

The 4th animation takes Uniq’s buoy animation in #544, adds red dots to mark each day at 06:00, cuts down to just one of the parallel buoy tracks, adds a GFS wind track out 24 hours from the final frame, and uses that to conceptualize where the buoy will be tomorrow (green line, red dots every 3 hours; scale is off). The buoy is an offset proxy for the Polarstern drift.
Title: Re: MOSAiC news
Post by: Jim Hunt on January 29, 2020, 06:55:02 PM
The relief icebreaker is not likely the Kapitan Dranitsyn as stated. The KD is not a proper icebreaker to begin with, cannot function in 3m waves when loaded with scientific containers. It got stuck already leaving in December ice.

Allegedly the relief "icebreaker" really is the Kapitan Dranitsyn:

This afternoon two tugboats pulled the Kapitan Dranitsyn out into the fjord and we began steaming (dieseling? doesn't have quite the same ring) North. Polarstern bound!
Title: Re: MOSAiC news
Post by: uniquorn on January 29, 2020, 11:04:24 PM
update on estimated polarstern position using P201,P204 and P207. Red dots are A-Team's recent calculated locations from S1 images(listed below). It wasn't possible to match all points accurately so best efforts were made at the more recent dates.

jan   Lat   Lon
280538   87.4517   95.8359
270636   87.4444   95.5836
140554   87.3973   105.4119
130335   87.309   107.9954
100627   87.1678   113.0994
70602   87.1201   114.9311
ani data attached as txt

Tech note: formula
dataPS$latitude..deg. <- ((1*data201$latitude..deg. + 2.8149*data207$latitude..deg.)/3.8149)
dataPS$longitude..deg. <- (1*data207$longitude..deg. + 0.002981*data201$longitude..deg. + 0.0028*data204$longitude..deg. )/1
Probably be ok for a few days. Couldn't find a good ratio for Lon
est north   est east   diff   
87.4543334399329   95.6513628566   0.002633439932893   -0.184537143399993
87.4203817793389   93.1496523462   -0.024018220661105   -2.4339476538
87.4016529083331   105.3507199407   0.004352908333118   -0.0611800593
87.3137762221814   108.0140101407   0.004776222181434   0.018610140700005
87.1742587669402   113.2169081828   0.006458766940156   0.117508182799995
87.1259043880573   115.0405318049   0.005804388057342   0.109431804899998
Title: Re: MOSAiC news
Post by: A-Team on January 29, 2020, 11:15:31 PM
Maybe the AK or another icebreaker will escort the KD? Unbelievable, the KD had to sit in a fjord for six days before the last trip, weather off Tromsø. Gear on deck sliding back and forth.

Or maybe the KD can retrace its last route. We could follow it for weeks as a white track. Not seeing it on the last 3 S1AB though.

Wow, look at the regional ice motion for the last three days. Orientation is rotated 180º to match Mosaic practice. Not quite enough resolution to match bow radar though 06:00 times are favorable.

Looks like we can patch the high resolution coordinate set between the buoys and older mos_mult. Haas might be open to releasing ship bearing and GPS data (?)

GFS is sticking to its story: a cyclone will graze the Polarstern tomorrow. Where exactly is hard to say because intermediate drift affects the details of the ship's position relative to cyclone structure. Scientifically speaking, this is an incredible opportunity to see close-up how the ice pack responds to a fast-moving circulating (and drifting) wind pattern.
Title: Re: MOSAiC news
Post by: A-Team on January 30, 2020, 01:32:30 PM
The ice off the port bow remains restless but continues to settle in. Pressure ridges and keels should be building as ice plates collide but that is not immediately apparent in the two frames, The Polarstern passed through a blast of warm air off the Barents; by the time the air completed the CCW cyclone circuit, it was a whole lot colder. The pink lines from awiMet show conditions at the times of the bow radar frames; the green pressure at 06:00 match the GFS timestamp.
Title: Re: MOSAiC news
Post by: uniquorn on January 30, 2020, 02:48:44 PM
drift update, pretty much due east again after 2 hairpin bends. Here introducing p193, making a grand entrance by obliterating the 87.4N label but should improve efforts at estimating PS location. P201 can take a well earned rest.
edit: updated to jan31 02:14, headed south temporarily.
edit2: T56 temperatures (every 6 hours) over the same time period (jan18-31), confirming the FoMo temps below.

The nearest Obuoy, 2019O4, with surface temp measurements every 10mins must have the sensor buried in snow/ice
Title: Re: MOSAiC news
Post by: A-Team on January 31, 2020, 11:42:50 AM
after 2 hairpin bends
The Polarstern enters the maelstrom later today; it may seriously contort tracks of the buoy array that accompanies it by midnight UTC. The bottom slideshow below scales the maximum view of GFS at Nullschool up 22.23x to match the scale of Uniq's buoy tracks. They are positioned very differently with respect to cyclone wind speed which increases drastically out radially (from 2 to 12 m/s). The position of the Polarstern is uncertain 12 hrs out, as is GFS.

Some km-scale shifts in the ice off the Polarstern's bow and port sides accompanied the twenty hour episode of double digit winds on Jan 30th. The white scale bar should be 250m not 25.

While waiting around for the KD to leave for leg 3, L Kaleschke made quite an interesting whole-Arctic mp4 of leads from "AMSR" from Oct 1st to Jan 31, archived as small individual grayscale tifs. The whole current set of 123 days open up to a reasonable 78 MB. This is a very important addition to the overly local (5 km) view of leads from the bridge radar.

Note this cannot be done from the AMSR2 png archive we use because in mid-winter even the large format images are almost entirely pure white, 255 (100% SIC). There's no information about leads in a block of pure color. Kaleschke's tifs use very light grayscale but only the pole hole is white.

The indexed coloring scheme resolution seems sub-optimal but alternatives are easy with ImageJ. The Polarstern track could be added though it is tiny at this scale; S1AB thumbnails and bow radar could be inset in wasted space. The leads could be extracted and overlaid on Ascat with 'darken only'. For that, all the leads, thick or thin, need to be pulled with 'threshold'.  no password needed
Title: Re: MOSAiC news
Post by: Florifulgurator on January 31, 2020, 01:17:09 PM
Sorry for OT, but... image processing in Java?  Does this thing really work?

It's been some time ago, when I had to program and/or use Java for graphics. Some of the most ridiculous (incl. dangerous) bugs/algorithms I've ever seen. Not to speak of the performance.
Title: Re: MOSAiC news
Post by: A-Team on January 31, 2020, 01:37:47 PM
image processing in Java?
Yes, ImageJ freeware was built by and for scientists doing advanced imaging analysis in cell biology and astronomy. It is extremely stable and fast with a large tool overlap with Photoshop and Gimp but many powerful ones of its own. It has a common code base with great updating but grows by independent contributed modules (.jars) that don't trip over each other as you add them. Most of these are implemented algos from mathematics-based IP journals. It is very convenient for complex manipulations of stacks (ie time series). One weakness is very limited 'undo'; another is alpha channel masking.

C Katlein, the ROV operator on leg 2, has been posting interesting photos almost every day (despite FoMo publicists repeatedly insisting the Polarstern's 100 mbps internet connection doesn't allow for this.)

Other people are tweeting about bear visits; these have been far more frequent than FoMo has acknowledged. These are not always seen by the bear guards; some visits alongside the ship are inferred from tracks. Both polar bears and foxes associate ships with food; people on the AF even fed them over the rails. 

The first image below shows the view from below: the ROV mapping the depths of pressure ridge keels. Only the z axis is provided so the xy scale relative to the Ice Camp and the five ridges being drilled isn't provided but probably is 500 m or so. Some of the keels go quite deep, perhaps 5 m; it's hard to say as palette colors don't match depth colors.

The ROV is also pictured measuring an ablation stake sticking out the bottom of the icepack. Ice, especially on keels, is lost frictionally from drift relative to stationary ocean water; deeper keels melt because they're situated in water above the freezing point. The sub-freeboard ice pictured is 0.9 m.

FoMo is reporting extreme bounces in ship weather today that are in mild contradiction to the weather data they send out to awiMet, sailwx, DWD (Germany's NWS), and ECMWF. This might result from using instantaneous data vs hourly means or from stations at different heights above the ice.

Oddly, Mosaic does not seem aware of GFS nullschool providing frequently re-initialized and so far quite accurate 3-hour views of wind direction and strength forming the basin-wide cyclonic weather pattern, despite having a full-time staffer on board from Deutscher Wetterdienst. All the comments to date take a purely point perspective whereas a synoptic view is essential to understanding where the warm and cold air are coming from, why the ice is fracturing and where the Polarstern will drift next.

Attached also is an edited list of 56 recent papers by leg 2 leader C Haas. His background is geophysics and main current interest observation-based sea ice thickness. Free full texts are easily located online by searching on the full titles; he also maintains a ResearchGate page. His most recent paper, moored sonars in the Laptev, has just gone into review at open source/open review Cryosphere Today (where he is an editor!).

Compare this statement from Haas to the data hoarding during leg 1:

One of the objectives of the CryoVEx campaign was to observe how snow and sea-ice thickness varies along a CryoSat track from the coast of Canada across the multiyear ice zone into the first-year ice further north.

A week after this part of the CryoVEx campaign was completed, data processing has progressed and we can present some first results. These will be invaluable for CryoSat and IceBridge data processing by the various groups, for assessment of the state of Arctic sea ice after an exceptionally warm winter, and for initializing predictions of summer ice conditions.
Title: Re: MOSAiC news
Post by: uniquorn on January 31, 2020, 08:55:31 PM
I dug out the old delaunay test program written using octave for an overview of buoy drift from 66 iabp buoys, jan1-31
No projection. - removed
Projected version below
Title: Re: MOSAiC news
Post by: uniquorn on February 01, 2020, 01:21:10 PM
Very nice amsr2 arctic lead product.
Some Pbuoy data yesterday was every 3 hours instead of 30mins.

Only showing 204 and 207 as there are some other odd data on p193 and p201
updated below
Title: Re: MOSAiC news
Post by: A-Team on February 01, 2020, 03:45:52 PM
As a tightly wound cyclone drifted over the Polarstern this morning, near-surface conditions went from 1 m/s under the eye to 16 m/s in single hour accompanied by a 180º shift in wind direction, then reached an expedition peak of sustained 19-20 m/s winds. (In other units, 20 m/s is 77 km/hr, 38.9 knots, 44.7 m/h).

Note the extraordinarily warm near-surface air temperatures in the early am: -11.5ºC. GFS has this at 11.0ºC. FoMo goes on with crazy talk about this warmth coming up from Svalbard despite the wind there blowing straight down the Fram. FoMo ignores the storm raging outside to share more trivia on microscopic plankton and cod minnows.

Better to have saved the life boat story for today? Some 90% of ship emergencies are due to fires on board. The captain has discussed the many preparations for that. Despite off-loading gear to the ice, many tons of untested electrical devices from 19 countries remain aboard.

Should the ship list seriously to port because of impinging starboard pressure ridge ice (on the Fram, these got higher than the mast), it won't be possible to launch half the lifeboats using eight guys tugging on a rope around a dislodged mooring I-beam. The other lifeboats might launch adrift in a corresponding port lead and so be inaccessible. Would it make sense to store some well-stocked lifeboats on the ice the whole time?

Without the Pistenbullys, an emergency airstrip could not be groomed. Indeed, we've not seen the promised follow-up on the trial airstrip of Jan 8th. It must have become totally inoperative within days from the daily ice pack grinding seen on bow radar; it would take an amphibious 4WD ATV to go down the runway now. This scenario could leave 150 people doubled up on half rations inside the functioning lifeboats for a month or more.

2020 AWI is recruiting 17 PhD candidates and 12 Postdocs to strengthen its new research program "Changing Earth – Sustaining our Future". Applications ar now open in the following research areas: atmosphere, ocean, ice and land; Arctic ecosystems and permafrost, marine and polar life marine bio-economy. Over €1 000 000 000 has been allocated to build Polarstern II.
How about €50/day to pay a science grad to oversee daily FoMo blurbing? Climate change --> no fisheries bio-economy in the Arctic or anywhere else after the ice melts, why throw resources at it.

The sharp curvature and high (and rapidly changing) gradient of the wind stress field will couple strongly to edges of pressure ridge jumbles and giant sails like the Polarstern side. The ship's orientation (bearing) is not disclosed so we don't know when the winds hit broadside or astern; there's no S1AB coverage today.

Pitch and roll are not disclosed either, though even the min-sub has a nice heads-up display of them. We can see from swings in the bow radar contrast and orientation that the ship is not really frozen-in but merely moored on the starboard side.

This is by design as the hull must lift up (rather than collapse) if pressured by ice on the side. The draft as currently loaded is ~4.0m so most of submerged parts (eg keel and propeller) lie in water too warm too freeze. An early FoMo photo out from the moon pool confirms this.

These high wind speeds will put record stress on the icepack. However today's bow radar will only cover the fracturing until midnight of Jan 31st; the event is continuing through 1500Z today. The drift is strongly to the Siberian south and slightly west ('to the right' of GFS wind as Nansen noted).

In the awiMET table, when their one decimal latitude and longitude "hold steady" despite sustained strong winds from 330º, that means the Polarstern is rapidly moving due south towards the New Siberian Islands. This will eventually show up as 87.3 latitude. (The Polarstern drifts about 7 km/day, 0.29 km/hr on Uniq buoy scale, under local winds speed averaging 6 m/s or 22.6 km/hr.)

Only minor plate readjustments on the port side have occurred so far, raising the question of time lag between applied stress and brittle failure. However a 4.2º CCW rotation of the bow took place in the 12 hours before midnight on Jan 31.

  87.4  95.9 20-02-01 18:00  08  330   -38.2 1000.7  third radar frame tomorrow
  87.4  95.8 20-02-01 17:00  09  330   -37.8 1000.1
  87.4  95.8 20-02-01 16:00  11  330   -37.6  998.9
  87.4  95.7 20-02-01 15:00  11  320   -37.1  998.1
  87.4  95.7 20-02-01 14:00  11  320  -36.2   997.1
  87.4  95.7 20-02-01 13:00  12  330  -35.4   995.6
  87.4  95.7 20-02-01 12:00  13  330  -34.7   994.4  second radar frame tomorrow
  87.4  95.7 20-02-01 11:00  15  330  -33.9   992.6
  87.4  95.8 20-02-01 10:00  16  330  -33.2   990.9
  87.4  95.9 20-02-01 09:00  16  340  -32.8   989.1
  87.4  96.0 20-02-01 08:00  18  340  -31.6   987.3
  87.4  96.1 20-02-01 07:00  19  350  -30.9   985.0
  87.5  96.2 20-02-01 06:00  19  350  -29.0   982.7  first bow radar frame tomorrow
  87.5  96.2 20-02-01 05:00  20  360  -27.6   979.8
  87.5  96.3 20-02-01 04:00  19  360  -25.7   977.3
  87.5  96.4 20-02-01 03:00  16  010  -21.6   975.2
  87.5  96.4 20-02-01 02:00  01  300  -11.5   974.6  gap of one hour
  87.5  96.4 20-02-01 00:00  07  190  -12.0   976.4  last bow radar frame today
Very nice amsr2 arctic lead product.
Very nice indeed! Kaleschke has been publishing on AMSR-E (passive 18.7, 89 GHz, since 2002) for 13 years including lead detection so this is not out of the blue -- but what sudden inspiration struck him there on the wharf? Hopefully updates will keep coming while at sea; posting time changes suggest a pipeline is not yet fully set up.

This will get us into Hough transforms, a familiar technique from image analysis used to detect sub-pixel geometric features such as linear leads. ImageJ plugins are totally on top of this.

Hough was automating bubble chamber decay analysis in the 1950's. In math, these have been known as 2D radon transforms from 1917 on. The inverse is used in medical scans.

In the case of leads, a time-dependent 2D+T Hough transform might sharpen the product. That is, OsiSaf describes basin-wide how ice is moving, meaning the day n+1 AMSRE can be brought back to augment the search of leads on day n. (For all we know, this could have been Kaleschke's processing breakthrough.)

Regionally, ice motion is available from consecutive S1AB pair overlaps which generally exist for the Polarstern area. Locally, the buoy swarm gives ice motion very accurately at 30 minute intervals; leads can be extracted from dispersion in the delaunay diagram (the GPS is precise, ice does not stretch). However the scale of buoy deployment is well below that of AMSRE.

Pressure ridges don't show up on that satellite but can be inferred to exist when a lead closes, provided that can be distinguished from freezing over. Tracking these features might identify multiple openings over time of the same weakness.

The Feb 1st lead frame is below, slightly modified. Note how the view is cut off well east of Banks Island and much of the Beaufort/Chukchi; the detectable leads detected are almost entirely in MYI.

The base map is the same projection but different scale as forum AMRS2. However that can provide convenient land and open water masks and a graticule at 124.98% enlargement. Note the pole hole is slightly larger in AMSRE-K but still well inside 89º. Ascat then needs to be resized by 2.2827 * 1.2498 = 2.8592 to take a dark or colored overlay from what we think is AMSRE-Kaleschke.

However even if the latter is cropped to the 'good stuff', it is still 770 pxls wide, whereas the forum limit is 700 so the above enlargements need to be dialed back by 10%. Assuming only MYI is left at the time of mooring on Oct 4th, it may make sense to use the AMSR2 open water to mask AMSRE-Kaleschke on all the latter dates since the leads (and Polarstern) are in the MYI and drift within the frame.

On the bright side, the 90º Eurasian quadrant of the Polarstern provides 350x350 pixels of AMSRE-K lead resolution, meaning it probably can withstand 2x enlargement or double up as is with 3 other resources as a 700x700 (alt 4:3 or 16:9 aspect) mp4.

Care must be taken with repeatability of crop boundaries, enlargements and contrast enhancements so that incoming Feb updates to the leads can be easily concatenated onto the current product.

Sea ice leads in the Arctic Ocean: Model assessment, interannual variability and trends
Q Wang, S Danilov, T Jung, L Kaleschke… - Geophysical …, 2016

Wernecke, A.; Kaleschke, L. . “Lead detection in Arctic sea ice from CryoSat-2: quality assessment, lead area fraction and width distribution”. The Cryosphere 9. (2015): S. 1955-1968.doi:10.5194/tc-9-1955-2015

Röhrs, J.; Kaleschke, L.. “An algorithm to detect sea ice leads by using AMSR-E passive microwave imagery”. The Cryosphere 6 (2). (2012): S. 343-352.doi:10.5194/tc-6-343-2012

Röhrs, J.; Kaleschke, L.; Bröhan, D.; Siligam, P.K.. “Corrigendum to "An algorithm to detect sea ice leads by using AMSR-E passive microwave imagery" published in The Cryosphere, 6, 343–352, 2012 ”. The Cryosphere 6 (2). (2012): S. 365-365.doi:10.5194/tc-6-365-2012

Gunnar Spreen, Lars Kaleschke, Georg Heygster, "Sea ice remote sensing using AMSR-E 89-GHz channels", Journal of Geophysical Research, vol. 113, 2008.
Title: Re: MOSAiC news
Post by: uniquorn on February 02, 2020, 11:21:28 AM
Some rapid drift south yesterday. PS has spent over 16days in this area.
300 frames @ 12fps (increased from the usual 7fps)
updated below

A nice job for someone to verify those leads at some point., feb02, rough mosaic area circled cffr
Title: Re: MOSAiC news
Post by: A-Team on February 02, 2020, 04:03:22 PM
Some rapid drift south yesterday. PS has spent over 16 days in this area. Verify those leads!
It may not work that well to compare infrared (heat leaks) to radar (salinity, SIC). Leads freeze over within hours at the prevailing winter temperatures; that will affect the two images differently. The infrared image has much better resolution during cloud-free days.

A lot can be done with this AMSRE time series from L Kaleschke, including visualization of whole icepack drift about as well as Ascat. Both suffer somewhat from incoming weather systems.

The major cyclone is affecting the ice around the Polarstern at quite a few locations but so far not as severely as the Nov 19th storm. That didn't really give rise to major chaos until the 22nd.

On the bow radar, the Polarstern at 118 m in length scales to just 12 pixels in length. A few multiples of that radius would pick up most of the instrument sites, the test runway, CTD and ROV  holes and other observation sites. The 3x enlargement is about all the image quality allows after enhancement. Almost all of the starboard side gets masked out in the archive for unknown reasons (the radars can provide 360º coverage as seen in N-ICE2015 data).
Title: Re: MOSAiC news
Post by: A-Team on February 02, 2020, 04:43:43 PM
A late S1AB surfaced for 06:02 on Jan 31st. The PS is at 87.4365 96.4841 on that image; the floe is quite altered in appearance. Some rifts are nearby that may have absorbed some of the wind stress.

The Polarstern (red asterisk) barely made it onto Sentinel coverage. The image is rotated 180º from PolarView to correspond better with Mosaic orientation. The blue arrow runs along the ship axis with starboard and port sides indicated. The bow radar points along this axis but is imaged as vertical. An extended rift (yellow arrows) possibly corresponds to a local shear line seen active above. The exit track of the KD is still visible as a white streak.

The second image is a composite of two consecutive Sentinel orbital scenes derived from the jp2 rather than the jpg. The blue ellipse shows a rift zone a ways from the Polarstern. This rift is difficult to date because coverage by Sentinel has been spotty with the ship dodging in and out of the pole hole in recent weeks.

Another S1AB just surfaced, for 02 Feb 2020. A remarkable rotation and translational drift of the Polarstern region took place during these 48 hours.
Title: Re: MOSAiC news
Post by: blumenkraft on February 03, 2020, 07:06:49 AM
The IcePod


The IcePod is the podcast about polar science and the people. We’ll talk to scientists who went on board Polarstern, the German research icebreaker, for the biggest research expedition in the Arctic. The IcePod is the official podcast of the YOPP

Link >>
Title: Re: MOSAiC news
Post by: uniquorn on February 03, 2020, 01:47:05 PM
drifted north west yesterday, arriving very close to last week's location
300 frames@12fps
Title: Re: MOSAiC news
Post by: A-Team on February 03, 2020, 04:44:37 PM
arriving very close to last week's location
Very effective visually to have tracks speed up as the drift speeds up. The km/hr scale has tripled to accommodate actual data (next post); scales are not the same in different buoy animations. Km/hr is the appropriate unit here; it's hard to picture a floe moving even one meter per second (SI extremism?). For glaciers, m/d makes more sense (Jakobshavn got up to 51 m/d).

The question is, do the buoys show this behavior every year but we just don't notice because their motion is commonly dumbed down to weekly resolution? I would say no, the wind pattern has been very peculiar this year -- and that's about to continue with strong poleward motion turning east.

Been there, done that, doing it again:

  87.4   94.0 20-02-03 18:00
     87.4   93.9 20-02-03 17:00
         87.4   93.8 20-02-03 16:00
             87.4   93.7 20-02-03 14:00
                87.4   93.6 20-02-03 13:00
                   87.4   93.5 20-02-03 12:00
                      87.4   93.3 20-02-03 10:00
                          87.4   93.2 20-02-03 08:00
                          87.4   93.2 20-02-03 05:00
                      87.4   93.3 20-02-03 03:00
                   87.4   93.5 20-02-03 01:00
                 87.4   93.6 20-02-03 00:00
             87.4   93.7 20-02-02 23:00
         87.4   93.8 20-02-02 22:00
     87.4   93.9 20-02-02 21:00
  87.4   94.0 20-02-02 20:00

The lead openings and closings are very active on a day by day basis though not much of that shows up on the Polarstern bow radar. The new scale bars are multiples of the 118m ship's length as almost all activity is nearby.

The Polarstern was in range this morning for a 06:00 Sentinel at 87.4 93.2. PolarView is just now back from its near-daily breakdown; nothing north of 86.9 is showing.
Title: Re: MOSAiC news
Post by: uniquorn on February 03, 2020, 08:28:50 PM
The km/hr scale has tripled (or typo)?
The scale is auto calculated by R. 0.481m/s(1.73km/hr) is pretty quick. Extract from P193 below.

I don't think that there are many previous buoys to compare to in this area. Perhaps someone will search a couple out. Drift may appear faster when hourly reports are missing, for example on jan31

Here showing most mosaic iabp buoys that report on the hour from sep29 to feb2. R was used to calculate utm lat and lon and the graticule as in the drift animations. The data was then run in octave to present the delaunay triangulation. A small mismatch in image size required rescaling of the  graticule so this is best efforts and should be seen as a guide only.
edit: The longitude labels are incorrect, they should be one place to the left. 135E is vertical.
Title: Re: MOSAiC news
Post by: A-Team on February 03, 2020, 09:25:37 PM
Drift may appear faster when hourly reports are missing
Slower? If the drift is A --> B  --> C  and the hourly is missing for position B, then the A --> C speed will be slower to the extent ABC are not co-linear (triangle inequality).

FoMo gave a dramatic example of this on Jan 14th (while omitting the key parameter, sampling interval). At a buoy track crossing, the difference in position (distance covered) is zero as is the speed but not the elapsed time.

The triangle inequality also holds on the surface of a sphere (or any Riemannian manifold) but lines have to be geodesics. The buoys are not constrained to move on geodesics (which become complicated in a hurry on the WGS ellipsoid).

Distances between two lat lon points are typically approximated with the sphere's haversine even if that geodesic doesn't follow along the actual buoy track. When the points are close (ten minute sample times, slow speeds, no jogs), the difference is utterly negligible and in fact ordinary lines on the euclidean tangent plane suffice.

The issue here is not the ice speed per se but how it got there, what keeps it there and what alters direction. In a situation like the central Arctic with negligible near-surface currents and tidal influences, this is mainly wind pushing on ridges but retarded by keels and drag with sea water.

Because of friction, there's no conservation of momentum: a floe in motion doesn't stay in motion. Kinetic energy is quickly being dissipated as (unnoticeable) heat.

Is there is such a thing as terminal velocity for ice (as for skydivers) and have we approached it during the Mosaic expedition. Yes, wind can't keep up with subsurface drag which goes up like the cube. No, because the 10-12 storms expected haven't happened; extreme winds so far have been south of Svalbard and east in the Barents.
Title: Re: MOSAiC news
Post by: uniquorn on February 04, 2020, 11:57:35 AM
The art of moving without moving.
Here breaking out best time detail with 715 frames at 24fps.
Title: Re: MOSAiC news
Post by: A-Team on February 04, 2020, 01:08:29 PM
art of moving without moving
Art of back and forth on Feb 4th: The three bow radar scenes are best processed individually because of contrast variability extremes within the master frames. They are all from the same date, Feb 3rd. Some of the leads, shears and ridging may extend into the Mosaic ice camp experimental areas or impinge on the planned port side airstrip.

The new archive of Arctic-wide leads extracted daily from AMSR-E by L Kaleschke are shown with exaggerated contrast under land and graticule masks from AMSR2. The red star at 87.5 95.0 shows the approximate position of the Polarstern.

It is not currently possible to definitively relate new leads seen on the basin-wide scale with much smaller features that can be seen at bow radar resolution.

T Lavergne's OsiSaf shows ice motion at a similar scale as AMSR-E. The two aren't readily compared because OsiSaf needs two days of data to get one picture of motion; further the data is gridded meaning the features used in AI are not retained or displayed.

T Krumpen is on different legs of the Polarstern (1a AF + leg 4 vs leg 3) than Kaleschke but both work at AWI so it reasonable to expect sea ice motion products to be improved soon. (Not in summer though.)

No S1AB today. The Polarstern will soon be in its pole hole again (but not that of AMSRE leads), followed by a full day of Fram-ward drift, followed by becalmed. What might be called aTPD (accidental Transpolar Drift).

87.5   95.3 20-02-04 14:00    8  180    -27.4 latest SIC review of over-estimates
Title: Re: MOSAiC news
Post by: gandul on February 04, 2020, 06:08:12 PM
I wonder if the Polarstern could be crushed if it gets close to Fram before Summer, as ice streamlines converge laterally as the ice accelerates (in the average motion), it is like people wanting to pass a small door in a panic situation. Would that be a real concern or the boat  should resist?
Title: Re: MOSAiC news
Post by: A-Team on February 04, 2020, 08:52:04 PM
The Polarstern has been on the job for 39 years. Its hull is designed to lift up when experiencing compressive forces from the sides. It's not clear what happens if the ship is torqued by forces at shearing angles. It has strain gauges welded on the lower hull but when frozen in, options are limited. Would the ship roll on its side or suffer structural damage?

In olden days, ships had  stout oak beams running abeam, seemingly crushproof. That design didn't end well for the Jeanette: 

On 7 Sep 1879, the ship became frozen in the ice at 71°N 175°E. For the next 21 months, Jeannette drifted in an erratic fashion, frequently doubling back on herself. On 12 June of 1881, the pressure of the ice crushed the Jeannette. De Long and his men unloaded provisions onto the ice and watched as the ship sank at 77°N 155°E [well south and east of the Polarstern).

Wreckage eventually came ashore on the central east coast of Greenland where it was discovered by Nansen on a field trip there. This inspired his theory idea of Transpolar Drift. It is evidence, along with carbon-dated beached logs at Morris Jesup, that the TPD (and Fram export) have been operative a very long time, even when the ice was much thicker and extensive than today.

Note the distinction: Transpolar Drift refers to surface ice blown by the wind; Fram export is return flow of Atlantic Water inflows that are ~300 m below the surface. The two often work together at the intake funnel of the Fram Strait at ~82º (East Greenland Current). Mosaic is tracking this double-diffusing Atlantic Water and its turbulent eddies at depth for the entire expedition.

However it's not immediately apparent from the buoy array tracks that the cw TPD -- which is air pressure pattern-dependent and ultimately driven by ccw earth rotation -- is operative this year.

The Beaufort Gyre, the other textbook staple, is still going around and around in the minds of True Believers despite irrefutable satellite evidence to the contrary. A Beaufort arm of floes derived from MYI ice off the CAA reaches up the AK coast to the Chukchi in most years but never completes a gyre. Today Beaufort winds are circulating in a nice gyre but in the wrong direction!
Title: Re: MOSAiC news
Post by: blumenkraft on February 05, 2020, 09:29:05 AM
Title: Re: MOSAiC news
Post by: A-Team on February 05, 2020, 01:53:22 PM
photo credit: Lukas Piotrowski
Here are 127 days of Ascat and AMSRE leads from Oct 1st to today. The Polarstern is currently about a third of the way from the pole to Severnaya Zemlya (87.5 95.0 20-02-05 09:00). It is feasible to overlay the leads and still see how the MYI ice on Ascat is drifting. Note the multiple origins of ice exiting the Fram.

The overlay of sea ice concentration derived leads on cry2smos derived thickness works well though thickness doesn't change much over the mid-Oct early-Feb time span. (Note only 103 days are available compared to 127 for Ascat and SIC leads because of a delayed start to cry2smos and delayed archiving necessity.) This new product AMSRE lead archive from L Kaleschke has enabled some important new visualizations.

No action today on the bow radar and none expected for the next few days as the ship drifts farther north and then east. The Polarstern will be within the pole hole of S1AB so no images will be available.

It would be instructive to make a one-day three-way comparison of infrared (#557 250m VIIRS brightness temperature, band I5 night), SIC leads and S1B. It is a little trickier to synchronize an overlay 24-hour leads on GFS nullschool winds which is 3-hour without file size getting out of hand.
Title: Re: MOSAiC news
Post by: uniquorn on February 06, 2020, 01:44:39 AM
Nice aspect ratio for wide screen. Some leads persist for a long time as lower concentration blobs.

Not many buoy 'proc' files were updated today. There are other unprocessed files providing latlon that we can use. Example from p201
24309464,"300234068912800","OSU-IT-0014",2020-02-05 21:00:25,10.5,3,87.524023,94.845873,0,,3,30
24309463,"300234068912800","OSU-IT-0014",2020-02-05 20:30:54,10.5,3,87.52297,94.856868,0,,3,30

Will look at that if they don't come back tomorrow. Different format so would require some small code changes.
Title: Re: MOSAiC news
Post by: uniquorn on February 06, 2020, 12:13:25 PM
data updated today, drift headed north west over  the last 2 days. Forgot to change the frame size so the ani is larger. ctr
770 frames@24fps
edit: corrected the longitude labelling.
Title: Re: MOSAiC news
Post by: Jim Hunt on February 06, 2020, 12:47:05 PM
Kapitan Dranitsyn is in amongst the sea ice, with nothing more substantial leading the way:
Title: Re: MOSAiC news
Post by: uniquorn on February 06, 2020, 01:45:27 PM
Probably not a bad route. Quite a lot of new refreeze on the way.
unihamburg amsr2-uhh, fjl, jan29-feb5. (north is left)
added a closer look from rammb (north is down)
Great, 3 images in a row with different orientation
Hmm, maybe they'll drop a few buoys in that area. That would be interesting
Title: Re: MOSAiC news
Post by: A-Team on February 06, 2020, 08:59:38 PM
not a bad route.
The temptation is to sneak along the lee polynya north of FJI. However the Kapitan isn't going to do that as it could easily slam shut, pushing the ship onto the rocks as the wind changes over to forming a lee polynya on the other side or below.

I don't expect the Barents to freeze over: too warm, too shallow, too windy, too mixed, too unstratified, too much Atlantic Water coming in below Bear Island. Every year people get fooled into thinking new ice is forming when the satellite mp4 show the wind has merely blown the ice pack through the island gaps. Again. St Anna trough is more nuanced.

The slide show below shows a couple of ways using Uniq's triple of buoys for patching the database of 196 S1AB images for an additional 34 missing Polarstern locations, a situation that has gotten much worse with the ship in the pole hole.

Basically, the close-in buoys move in parallel curved tracks, more or less keeping their distance and defining a stable triangle. Adding in a known high precision of a nearby date with PS location establishes a fiducial quadrilateral that can be moved and re-located at three buoy points on a frame timestamps that lack a PS location. The lat lon can then be read from the graticule or pixel coordinates.

Mosaic_mult has quit; they were privy to the ship's precision GPS and plotted it even when the Polarstern was off the latest S1AB. Since their images came with high resolution graticules, the earlier lat lon could be read off that (or interpolated from flanking locations on slow dates).

Once a complete set of once-a-day 06:00 locations are known, the track can be drawn in GoogEarth with pop-up links at each point along the path to the radar image, GFS nullschool of that hour, local buoy radar of ice motion, and global AMSRE leads.

Update 1: added a png showing how Polarstern lat lon can be measured directly off S1AB radar scenes: (1) find the ship which is a bright radar reflector with a stable pattern of floes around it, (2) zoom in 1600% with the BAS IWS viewer provided at PolarView, (3) capture the lat lon at the middle of the ship, (4) transcribe the data (5) check to see if consistent with approximate lat lon at sailwx and MET, (6) check on PolarView jpg graticule, (7) repeat on a later date for reproducibility.

Each of the steps can go wrong! Rechecking everything for the date with the biggest longitude anomaly at Reply #427 for 27 Jan 2020 shows the S1AB method seems to have produced an accurate reading of the PS location.

Update 2: added a distance scale to the graticule. Here a 0.1º difference in latitude corresponds to 11.1 km and a 1.0º difference in longitude amounts (at 87.5º latitude) to 4.85 km. These are the dimensions of full graticule grid cells. The buoy graticule may need adjustment;it is added manually after the tracks are calculated.

Here buoys and Polarstern are being plotted to a tenth (1110m x 485) or maybe even a hundredth of a grid cell 110m x 49m). With FoMo reporting a 1000m shear off the port side disrupting the ROV site and bow radar showing multi-km disruptions almost every day, the scale of ice motion distinct from joint passive drift is commensurate with these sub-grid scales.

Note too that GPS readings at extreme latitudes can be disrupted by solar flare, meaning a perfectly functioning buoy GPS will not really be reporting to the accuracy of what it says on the box.

All this means buoy and Polarstern locations need to be taken with a grain of salt. Accuracy depends on the precise timing with respect to leads opening and closing and shearing forward and back.
Title: Re: MOSAiC news
Post by: uniquorn on February 06, 2020, 11:49:40 PM
Gulp. Those calculations would be great if my labelling was correct. p193 ends at  87.5737,96.4523 on the last ani. I've corrected the labelling which is still done manually.
Title: Re: MOSAiC news
Post by: uniquorn on February 07, 2020, 10:47:39 AM
drift update, headed north west again yesterday. Here showing only points and coordinates. ctr
Title: Re: MOSAiC news
Post by: A-Team on February 07, 2020, 02:27:31 PM
how are lat lon of Polarstern calculated from buoys and/or S1AB?
See update in #575. Buoy and ship positions dependnot only on ice pack drift but also on the timing of position reports relative to shears and other displacements which are of comparable scale.

The latest bow radar is showing significant ice pack motion at numerous sites within its viewing window that presumably are representative of a much broader area including the Mosaic experimental sites and beyond.

The 6-hour bow radar imagery is shown together with 6-hour GFS winds but understanding causation requires looking at large-scale two day ice movement on the Siberian side induced by the stationary anti-cyclone between Wrangel and NSI, as displayed well by the ANSRE leads resource.

The Polarstern's floe is being squeezed between two shear plates, the ice accommodates the stress on it by over-rafting into pressure ridges and keels. Analysis continued in #581...
Title: Re: MOSAiC news
Post by: Tor Bejnar on February 07, 2020, 02:52:54 PM
drift update, headed north west again yesterday. Here showing only points and coordinates. ctr
Curious that, although there is no trail of buoy locations, the lat-long grid is erased by the progression of buoy location lat-longs.  Therefore, you can 'sort of' see where the buoys have been earlier in the GIF. (If not one sort of memory, then another!)
Title: Re: MOSAiC news
Post by: uniquorn on February 07, 2020, 04:17:07 PM
the lat-long grid is erased by the progression of buoy location
macid's original code uses R gganimate to create the animations. Adding the graticule from plotSvalbard slows down the process by 5-6 times, making a 5m job take 30mins. So I use a tip from A-Team to create the graticule with a 2frame animation, which takes a minute, clean up a couple of buoy dots, delete the second frame and insert it into the long animation at frame2.
Add an alpha channel to the frame, set white to transparent and merge it down to the first frame.
Much quicker, but the buoy paths overwrite the grat as they go along.
It's eco, saving the planet by using less processing power lol
mostly running on solar for 8mths/yr

Had a look for KD on S1B but all I could find was this. Looks more like a plane. cffr
Title: Re: MOSAiC news
Post by: A-Team on February 07, 2020, 05:10:51 PM
The circle, arrow and text overlay tools are confusing in ImageJ. Set the palette color, draw the overlay on the ROI, then Edit --> Draw to flatten your overlays into the base image. Otherwise the overlay will disappear with no undo! Maybe try RAMMB to locate the KD, rotate that by 105º CW and rescale to overlay on the jp2 version of PolarView which has mouse-over lat lon.

The prospects for the KD not being able to reach the Polarstern at all or getting permanently stuck on the return trip (with all the leg2 scientists aboard) are a definite concern.

Continuing the analysis from #578, the Polarstern's floe is being squeezed between two shear plates that hit at oblique angles with a delay of six hours or less, first from the left (port bow) and then from the right (port quarter). This is one of the few sequences where the coupling between events can be seen cascading throughout the bow radar view as the ice accommodates the squeeze by over-rafting into pressure ridges and keels. The mp4 is rotated 90º CW; the b/w scale bar is in multiples of the 118m ship length. The Polarstern's bow is at the b/w hemispheres, the stern is at the end of the first black bar.

The Ascat pair supplements the AMSRE leads pair above but shows the active and inactive zones more clearly in the two difference frames. The GFS anti-cyclone is above the active zone; the thick and resistant central MYI is more or less immobile. The Polarstern was on the boundary between the two zones.

Band 15 etc at WorldView are partly obscured by clouds and has confusing radial swathing so an ice motion pair there is not feasible.

The gangplank and Ice Camp area are abaft the starboard beam...
Title: Re: MOSAiC news
Post by: blumenkraft on February 08, 2020, 11:11:21 AM
Some points from the recent Arctic Drift Podcast:

The temperatures are low at the moment. Christain Haas talks about that there is less snow cover as expected (half the average) which allows the ice to grow in thickness due to the lack of insulation. Even though the wind wasn't too strong, vast parts of the ice are without snow, high snow dunes on other parts.

Then he talks about the pressure rig observatory. They found algae and fishes with the ROV in cavities.

He mentions the rifts that opened in the vicinity which they are using now to do thermal and chemical measurements and observe how new ice develops.

They found out from ice core measurements that there were sediments in the floe which allows them to make assumptions about its origin. It appears it is from a shallow Siberian shelf.

The helicopter flights seem less of a hassle as it was expected. Haas seems happy everything is working so well with them. Of course, this is important to maintain, clean and activate the equipment, change batteries, etc.

A rotating laser scanner is giving them ice-roughness maps. They categorize ice types this way and use this data for the still to build runway.

The crew change that will replace Lag 3 will be via airplane. They need a 1500m runway with at least 1m ice thickness so plains with weels can land. The development of pressure rigs and rifts has rendered some potential areas useless as a runway.

Link to podcast in German language >>

Title: Re: MOSAiC news
Post by: uniquorn on February 08, 2020, 12:12:41 PM
PS drifted gently north yesterday, shorter timescale, feb1-8
256frames@12fps -updated below
KD heading for a lead at 0320utm this morning, 88 82.25N 68.77E, barely visible on the jpg, not sure how long this link ( to the jp2 viewer will last
Latest position from cruisemapper is 82:39'35", 74:23'58". It appears to be following the line of the lighter, probably newer ice

edit: Cruisemapper Local time 2020-02-08 19:31, sailwx data stops on feb4

Title: Re: MOSAiC news
Post by: uniquorn on February 08, 2020, 02:52:00 PM
It's rush hour. Which is KD?
Title: Re: MOSAiC news
Post by: A-Team on February 08, 2020, 03:47:54 PM
82.25N 68.77E, barely visible on the jpg
not sure how long this link to the jp2 viewer will last.
A lat lon time for KD on sailwx or cruise locators to remove white dot ambiguity and identify interlopers? Not seeing a swath, maybe seals up too fast or takes thicker ice or they've been in a lead.

Links last many months, unlike at the PolarView portal which only stores the jpg for 30 days. The url preserves the all-important auto-generated hexadecimal, here 46F8_N_1, which is essential to finding the big package on the awkward Copernicus Sentinel portal. The is a huge breakthrough for the end user.

I've safely archived all the jpgs and lossy jp2 links containing the Polarstern back to Oct 4th mooring. The attached cvs contains direct viewer links to all the jp2 scenes as well as to GFS weather of their date and hour.

Below all 373 scenes to date of Polarstern bow radar are collected in two mp4. The second of these (3x) examines the history of the peculiar area just in front of the bow that has seen bad shearing but has since been stable for months. These are uniformly brightened and sharpened with mild local contrast (CLAHE 63 1.75 in the montage).
Title: Re: MOSAiC news
Post by: uniquorn on February 09, 2020, 11:25:08 AM
Headed steadily north west
Chaperone? 82.85N76.0 and 82.88N76.77 (

Title: Re: MOSAiC news
Post by: A-Team on February 09, 2020, 02:16:08 PM
KD is making good progress two hours later. It measures ice thickness, not by the silly system of people comparing a painted yardstick to overturned ice but by a EM induction instrument projected from the bow.

This totals thousands of km of swath data by now that would have helped in comparing various observational and model approaches to this key parameter. However the thickness will not be divulged until 2023 when no one will have the slightest interest. [We call this 'dog in the manger' science after an Aesop fable.]

The KD is in a dense coverage area of S1AB; however we won't see the PS and KD join up because the PS is going ever deeper in the pole hole this week to 88.0º.  We can expect the KD to use its previous track coming in so as not to create yet another damaging swath near the study area.

At the three L-sites within the MOSAiC Distributed Network (~15 km distant from Polarstern at the beginning), the project will install Atmospheric Surface Flux Stations (ASFS) that include measurements at 0-3m height of pressure, temperature, relative humidity, high-frequency three-dimensional winds, high-frequency water vapor and carbon dioxide concentrations, surface height (snow depth), surface infrared temperature, surface heat flux, and up- and down-welling longwave and shortwave radiation.

Adjacent to these atmospheric surface flux measurements at each of the four locations will be an ice mass balance buoy for measuring ice thickness and thermodynamic structure, and an Autonomous Ocean Flux Buoy for measuring ocean fluxes of heat, momentum, and salt. Jointly these measurements allow for a full documentation of the thermodynamic state of the sea ice.

Additionally, an array of GPS position buoys will be installed across the full MOSAiC Distributed Network to provide detailed information on ice dynamics.  page 36
The Polarstern lost an important piece of remotely deployed atmospheric flux equipment yesterday; unfortunately the Kapitan Dranitsyn is not bringing a replacement as it had already left before the pressure ridge occurred. Mosaic did not share the previous loss of function of this device, its earlier repairs, nor even its approximate current location.

This used up quite a bit of helicopter fuel; the KD will be bringing more. However between legs 3/4, only planes can reach the PS. The 1500m runway is very much in doubt currently due to constant development of pressure ridges, leads and offset shears. Planes are primarily for staff exchange; they cannot bring in fuel.

This hole by the gangplank ... what were they thinking? It freezes over from cold ice on the sides (so use 4x8 marine plywood insulated with foam) and from the cold air (use 8" foam board cover, not a complex flimsy tent that cannot be set up in wind). Any lumber yard in the US would have these. Immersion heaters? -- the hole is not even hot tub-sized and just a few meters from ship power supply. $29.95 per 3000W @ ebay.

We have seen so many times that gear testing back home (Bay of Bothnia? ice-fishing in Minnesota?) would have greatly reduced data downtime at Arctic drift sites. No record of downtime has been disclosed and never will be.
Title: Re: MOSAiC news
Post by: uniquorn on February 10, 2020, 02:16:59 PM
drift update, still headed north west, picking up speed again.
No polarview of KD area today so here is best I could find through cloud on rammb day/night band ctr
Lat line is 82.5N
KD at 83.7N 79.73 at 2020-02-10 19:00 local time
Title: Re: MOSAiC news
Post by: A-Team on February 10, 2020, 03:04:08 PM
still headed north and west, picking up speed
This Polarstern drift will continue strongly in this direction for several more days due to a persistent anti-cyclone to the north of Wrangel Island. Tailwinds will reach 10-12 m/s which are sub-gale strength.

The ship was at lat lon 87.8 91.7 at 1200Z today and will reach 88.1 86 later in the week, putting them in peak transpolar drift position. The concern has gone from them milling about for months in the Central Arctic to reaching the Fram four months ahead of schedule.

Fram export has really picked up under these wind conditions though it has been steady since mooring. It's very unusual to see the Fram  'intake funnel' of curved concentric leads extend up and past the north pole. This development will become even more extreme this week; the significance is the last of the very oldest and thickest MYI is being drawn down towards export.

The Fram situation seems completely uncoupled to the Nares-Banks Island ice above the CAA. Nares export has ceased for the time being.

An unusual collision of a very large ice plate with the Mosaic floe happened yesterday a couple of km off the bow over just six hours. A small pressure ridge much closer to the Polarstern has also developed off the port bow in the vicinity of the proposed airstrip.

If L Kaleschke is able to add a few earlier years to the lead visualization archive, it might be possible to test the proposition that ice motion has really gotten worse this year. These leads add a large number of trackable features allowing much higher resolution to description of motion.
Title: Re: MOSAiC news
Post by: uniquorn on February 10, 2020, 05:11:40 PM
Polarstern just visible on rammb north of the 87.5N graticule.
Title: Re: MOSAiC news
Post by: A-Team on February 10, 2020, 05:45:04 PM
This seal is a very long ways from the nearest open water. No photo of it on FoMo today. Seals don't just dive and take their chances on finding the next open lead when they need to breathe -- so presumably a maintained breathing hole is near the Polarstern. Ringed seals will also use cracks and gaps in the ice cover (such as tracks from relief icebreakers?).

Ringed seals have 2.5 cm long claws on their fore-flippers and can dig holes through 2m ice. The ice at the ROV hole is just over a meter thick; maybe the seal will do a better job of keeping it open.

But how can they catch fish underwater in mid-winter when it is dark already on the ice surface  and much darker below? They hunt under the ice for schooling fishes (particularly polar cod) and pelagic invertebrates but possibly also copepods etc living on the underside of the ice probably using whiskers.

Six seal species live in the Arctic: harp, hooded, spotted, ribbon, ringed, bearded. The latter two use breathing holes in the ice. Most of the ringed seals' time is spent near shore ice, but their ability to maintain cone-shaped breathing holes—which the animals excavate in the ice using the claws of their front flippers—allows them to occupy areas much farther from the ice edge than other seals can reach. Physiological adaptations help them make deep, sustained dives, reaching depths of 300 feet and remaining submerged for up to 45 minutes. But before surfacing, they sometimes blow bubbles up their breathing hole to check for polar bears, their main predator.

Feb 4
Today we had a #seal in the #ROV hole, and a fish in the zooplankton net.
Almost the entire ecosystem, except the top predator... yet #icedrift
Feb 3: so was it strong or weak?
Today we measured #seaice strength with a Borehole Jack from #NTNU #icedrift

See: Engineering Properties of Sea Ice
Journal of Glaciology 19(81):499-531 1976
DOI: 10.1017/S0022143000029476

Feb 2: more gear sank:
After moving operations from yesterday to today due to windchills down
to -59°C, we were deploying sediment traps with the #ROV again.
Unfortunately one had to be sacrificed to Neptune.

126 buoys deployed, 87 time series available:

Während der MOSAiC Expedition wurden bereits 126 Bojen ausgebracht. Die Daten und Messzeitreihen [time series] von insgesamt 87 Bojen können jetzt schon über abgerufen werden. 
Title: Re: MOSAiC news
Post by: uniquorn on February 11, 2020, 01:12:41 PM
drifted westnorth yesterday ;)

Christian Katlein@CKatlein
26 Jan
When he realized, that he won't drift to the pole, #Nansen went North by
skis. As we likely passed our northernmost point, we did the same ... As
we are already 150km further north than he ever reached, we only walked
for 1 hour and camped only 1 night to test our survival
Maybe they'll go camping again

tech note: nullschool locations are from p207, the northernmost buoy. The title is incorrect. It should say P201, 204 and 207. P193 often, but irregularly, misses ~2hrs of data so I went back to 201.
Title: Re: MOSAiC news
Post by: uniquorn on February 11, 2020, 03:09:38 PM
So many bright dots on S1 images. cffr (07:01:03 today)
KD 84.1N81.4E 2020-02-11 18:57 local time
Title: Re: MOSAiC news
Post by: A-Team on February 11, 2020, 09:24:59 PM
PS flew west & north yesterday 
Another 48 hours of that coming. The Polarstern reached new lat and lon records of 87.8 89.2 at 19:00Z which is 245 km from the pole and 919 km from the entrance to the Fram Strait. The weather pattern is pushing the whole Euro side of the icepack in that same direction.

That is shown in a 62-day Ascat below. The darker areas are thick MYI ice; significant pieces of it (though not the Lincoln Sea and west) will irreversibly enter the export staging area if the GFS winds keep up as expected. Not unrelated: the Arctic Oscillation index just hit a new high.

The bow radar we've been looking at is a ~10.0ghz product called a sigma S6 Ice Navigator system made by Rutter Inc of St Johns NL ( It's also been installed on the Healy and RV Lance.

The radar is operated by bridge command only and never before have scientists requested it for Polarstern research. The 1.5m wide X-band antenna is mounted on starboard side of platform B in crow's nest.

It does not seem to have been configured properly (to compensate for motion using feedback from gyros) resulting in images not nearly as sharp as they could be. The whole control panel has been cropped out in the meereis archive.

The basic purpose when the Polarstern is underway is distinguishing between open water, ice pans, open water leads in ice fields and ice ridges that can trap icebreakers. In open water the ice radar detects small bergy bits and growlers (large and small glacier calving pieces) that can significantly damage a vessel.
Title: Re: MOSAiC news
Post by: uniquorn on February 11, 2020, 09:32:45 PM
persistent anti-cyclone to the north of Wrangel Island.
Hopefully not too far off topic, that shift is allowing significant leads to open in the ESS., ESS, feb6-11. ctr
Title: Re: MOSAiC news
Post by: uniquorn on February 12, 2020, 11:38:10 AM
drifted west and north. Map from FoMo ( inset
250 frames@24fps. Interesting that the map is Greenland down (Perhaps it is a Nansen original)
Title: Re: MOSAiC news
Post by: A-Team on February 12, 2020, 01:16:30 PM
That is a surprisingly large westward component. And increasing, despite a steady wind bearing. Seems like is it 'should' have been more northerly with less of an eastward component.
Title: Re: MOSAiC news
Post by: Tor Bejnar on February 12, 2020, 02:54:35 PM
If "North" is to the lower left of the GIF, aren't the buoys drifting northeastward?

Also, I'm confused with A-Team's "... surprisingly large westward component ..." and "... less of an eastward component."  [The "eastward component" is what I see in Uniquorn's GIF.]

I'll be glad to be straightened out!
Title: Re: MOSAiC news
Post by: A-Team on February 12, 2020, 04:41:41 PM
Polar coord directions are confusing! Winds from the south? Not terribly descriptive at Pole. Being straightened out on the earth ellipsoid would be quite uncomfortable.
One way to remember is the "Far East" (in the eurocentric view) is Asia. Western Europe is west of that though east of the US East Coast which is west of the UK.

It all revolves around the Greenwich meridian. That runs through the center of the Fram Strait west of Svalbard. Going CCW from there is east; CW is west. The Polarstern is steadily losing east longitude (0.1º per hour) because it is going west towards the 0º meridian. Our maps use 'Greenland down' which is 45º west rather than a 0º vertical.

The leg 1 Polarstern staff voted to have all their maps point north. Maybe we could vote, though the world would take little note, to make east west and west east and move the 0º meridian to Greenland? How would that work for the South Pole? Let's not go there.

The mp4 follows ultra-local bow ice motion during the time the Polarstern has been under steady tail winds straight from 110º (time frame of Uniq's #596). These winds will perhaps continue another 81 hours to 02/15/0000Z (it's 20-02-12 15:00 now).

The question is, where will the PS track be by then? 88.05 79ºE. Will there be extreme motion in the bow radar and if so, why then and not the last two days?
Title: Re: MOSAiC news
Post by: Tor Bejnar on February 12, 2020, 06:53:28 PM
Unicorn's GIF (,2906.msg249323.html#msg249323) shows the trace of buoys moving over a period of time, with a 'running commentary' of the 'current' location's Lat-Long.  The lines of longitude get closer in the lower left corner, so "North" is in that direction.  From the perspective of (or watching from) the North Pole, something traveling eastward will be going from right to left, England to Russia, and westward will be going left to right, Russia towards England.  Traveling westward on the Eurasia side of the Earth the ("E") longitude numbers go down.

Clearly the buoys are going left to right so they are going westward, and as the longitudinal number are going down, the Kara Sea is off to the upper right of the map.  We can also determine that the latitude parallels are at 0.1º intervals and the longitudinal lines are at 1.0º intervals in this presentation.][/li]

Got it (for now). [And no wonder my tectonics professor once claimed I must be a member of Flat Earth Society!]
Title: Re: MOSAiC news
Post by: gandul on February 12, 2020, 08:15:56 PM
Furious winds in seven days according to ECMWF
Title: Re: MOSAiC news
Post by: psymmo7 on February 13, 2020, 11:44:01 AM
Here is an English transcript of the latest podcast from the MOSAIC website that is otherwise only available in German.

Posted last Sunday (February 9. 2020) at 9:02 AM

Installment 12 – little snow, lots of new findings & “Gurki”

In this installment expedition leader Christian Haas reports lots of new findings that have been gathered in various scientific areas of the  MOSAIC expedition. One finding among them concerns the  formation and original provenance of the various ice types. In addition, during the last few days, various living organisms have been found in the ice. Haas describes the current status of the programme for  building a landing strip and gives an insight into various  kinds of methods and  measurement techniques.

Commentator: Arctic Drift – the Audio Logbook.

Christian Haas: Today is one of the coldest days that we have experienced till now, about minus 34 degrees. But luckily the wind is not particularly strong, only about force 3, so that the wind chill temperature is only about minus 45 degrees.
Commentator: Very low temperatures continue to prevail in the Arctic. Despite this the researchers on the MOSAIC expedition observe similar climate alterations to those that are currently occurring in Europe. There is also comparatively little snow in the Arctic. The expedition leader Christian Haas explains why this change has consequences for the ice and why the researchers welcome any change in the condition of the snow.

Christian Haas: During the last few days we even had Strong Wind event, with force 5 to force 6 winds. That isn’t exactly a storm but, of course, given the temperatures that we have here, it felt very, very cold. What was fantastic about it, was that the snow was redistributed: that means that it was blown away from some places and piled up in other places in deep drifts. These drifts were several decimeters deep and several meters wide and long. As a result, the landscape quite clearly changed in the course of the last few days. However, just as before, there is still very little snow: on average between 9 and 12 centimetres, which is really a lot less, about half the amount that we would expect from long term climate records. That leads to the ice being able to grow thicker than it would be able to if the snow was deeper. This follows from the fact that snow has very good insulating qualities and very low heat conductance. Therefore a thin snow covering has the effect that the ice can lose more heat and can grow faster as a result. If the snow were deeper, the ice would grow significantly more slowly.

Commentator: In the previous installment Christian Haas already told us at some length about the various kinds of instruments that were being placed in the pressure ridges. The first measurements and observations from the so-called Pressure Ridge Observatory are bringing results.

Christian Haas: Yes, a few weeks ago we set up the Pressure Ridge Observatory. That meant that we installed a large number of measuring instruments in a large pressure ridge to observe how the ice grows in  the cavities and under the thickest ice and how the pressure ridges affect turbulence under the ice. Currently we are making the first investigations with our ROV, our remote-controlled unmanned submarine that is equipped  with cameras and is able to take samples. And, just as we hoped,  we found fish, even now in winter, in the cavities - the openings in the ice keels that occur in the pressure ridges between the ice blocks. Small codfish that spend the winter hiding there. We also found the remains of algal mats that will start to grow as soon as the light returns and will serve as a food source for these fish.

Commentator: Intensive research is also going on in other scientific  fields. As the result of new ice movement and a split in the ice inside the camp new insights could be gained into ice formation.

Christian Haas: During the last few days we had a lead opening event and a strong ice deformation event even though the wind wasn’t particularly strong. However, because the ice is drifting continuously  there are always  local differences in drift speed and drift direction. That happened now in our vicinity about 2 kilometres south of the ship where a lead opened and an open water surface about 20 metres wide and several hundred metres long was exposed in a relatively short period of time. This event was very welcome, because it enabled us to investigate the processes that occur when water is exposed in this way, how quickly it loses heat and how ice forms on it  and how thick it gets. So, several teams rolled out on the day it occurred and set up their instruments around the lead and made measurements for hours and in some cases days. They measured the water vapour above the  lead and how this affected the warming of the air. They also measured how new ice came into being in the form of  so-called frost flowers and the chemical processes that accompany it.

Commentator: In addition, the results of the ice-core-drilling programme  have provided information about the place where the ice floe originally came from.

Christian Haas: Once a week we have an extensive ice core drilling programme where we drill ice cores from different types of ice to examine their chemical and biological properties. This week for the first time we found a core that was full of sediment from the sea floor. At the moment we have 4000 metres of ocean beneath us, so it’s a fairly natural question to ask how the sediment got into the ice. But this sediment is a clear indication, if not proof, that that our ice floe was formed in the very shallow water of the Siberian Shelf. The water there is only 20 metres deep and if the wind is strong while the ice is being formed sediment can get trapped in the ice. The sediment then drifts with the ice and we can use it as a reliable tracer for identifying the origin of our  floe.

Commentator:  Research doesn’t only take place on the ice.  Airborne  missions with helicopters help the crew work more effectively by allowing regular maintenance of automatic monitoring stations that are several kilometres distant from the ship.

Christian Haas: One aspect of our activities here that’s very successful, although we haven’t said much about it yet, is helicopter flights. It wasn’t clear how well it would be possible to fly in the dark. Flying in darkness is very challenging. We took a lot of effort to prepare the helicopters for it by providing them with the right equipment for night flying. The pilots and mechanics also had to undergo special training in order to be able to undertake night flights here.  Fortunately, the effort has paid off. Because we have had really very good weather conditions, we have been able to carry out a large number of flights. We not  only made survey flights with the laser scanner in the neighbourhood of the ship, but we also have a network of automatic monitoring stations in an area between 10 and 50 kilometres from the ship and we have been able to visit some of these locations and in some cases to land there. We installed lights on them that can switched on by remote control, to save battery power, and in this way we were able to visit them and carry out maintenance tasks such as cleaning them, replacing batteries or reactivating them. 

Christian Haas: Another important aspect of the helicopter flights is that we carry out measurements of the thickness and  surface roughness of the ice. We do that with a laser scanner that measures the height of the helicopter over the ice with a rotating laser beam so that we cover a roughly 300 metre wide track along the flight path. By flying criss-cross over the ice in a grid pattern we can use this track to map large areas and can get a good impression of the type of ice  and its surface properties.  The maps that we produce in this way are our most important tools for being able to navigate through the ice, because otherwise we have neither photographs nor high resolution satellite data. An important feature of these freeboard and roughness maps is that we have used them to identify possible locations for siting the landing strip that we are going to construct during the next few weeks.

We need this airstrip for the crew exchange between the third and fourth legs of the expedition, because we can only accomplish this  using larger aircraft that land on wheels.   

The  landing strip will have to be one and a half kilometres long and on ice that that is one metre thick. We have already begun to look for such possible sites and the laser scanner maps were an important tool for doing this, because we could distinguish between areas that were relatively flat and those that were uneven because of pressure ridges. Of course we like to construct the landing strip on a relatively flat area, because it would be very laborious to have to try and remove and flatten humps and pressure ridges with the Pisten Bullys. Unfortunately the recent deformation- and lead-opening- events have destroyed some of the potential sites so that we must now wait until the situation has stabilized and then make new survey flights to confirm whether the sites we identified earlier are still suitable before we can begin with the construction of the landing strip.

Commentator:  The laser data and the survey flights aren’t just important for the construction of the airstrip and the maintenance of the automatic monitoring stations. The movement of the ice can also be followed and analyzed using aerial data. 

Christian Haas: At the moment the  laser scanner data are the most important way for us to be able to observe the movement and deformation of the ice. For instance, to see exactly where leads open, where pressure ridges occur and where floes are colliding.  . During the lead-opening event that we already mentioned we were successfully able to survey the area with the laser scanner for several days and to follow how the ice opened up in some  places but was pushed together in others until leads were completely closed   and the last strong convergence event took place. A convergence event is one where ice floes collide and are pressed against each other with such force that they break up and pressure ridges are formed.

Commentator:  Whereas the helicopter pilots work at an altitude of several kilometres [Ed. sic – this is really what he said – I know it’s nonsense], the marine biologists are researching at a depth of several kilometres and made a rather remarkable discovery.

Christian Haas: A special highlight of each week are the net catches of the biologists, who lower their nets several thousand metres deep into the ocean from the side of the ship and catch a variety of living organisms including algae, zooplankton, small amphipods and jellyfish.   The shrimp-like amphipods are the most numerous.  But this week we had a rather special surprise, because we caught a ca. 10-centimetre-long animal that was a very bright red. We haven’t  identified it yet, because there are so many different species that not every  biologist can be expected to identify them all immediately, but because it looked like a cucumber we called it “Gurki” [Ed. “Gurki” is a diminutive form of the German word for cucumber  “Gurke”]

Commentator:  You will be able to find out whether a suitable site can be found for building the landing strip and what new findings there are from the various scientific investigations  in the next installment of Arctic-Drift the  Audio Logbook.

Commentator: AUDIO NOW.
Title: Re: MOSAiC news
Post by: uniquorn on February 13, 2020, 02:03:59 PM
drift speed increased yesterday, mostly west, a touch north, feb10-13. Data for P204(middle) stops earlier than the others at 00hrs
Title: Re: MOSAiC news
Post by: blumenkraft on February 13, 2020, 04:47:36 PM
A MOSAIC timelapse video showing the time between 05. and 21. Oktober 2019.
Title: Re: MOSAiC news
Post by: A-Team on February 13, 2020, 04:57:28 PM
MOSAIC_AUDI :) L :) G B :) :) K
Weird that they don't provide the date of the interview. A couple of weeks old?
Furious winds in seven days according to ECMWF
That gradient would give rise to a strong CCW cyclonic push towards the Fram. The last of the CW circulation right now is sending the Polarstern that way at a rapid clip. GFS foresees another 18 hours of this before the ship is becalmed and even moves back the other way. Bow radar has been uneventful so far during this run towards Svalbard.

The new SIC-Leads product gives a considerably more nuanced picture of ice pack motion than gridded OsiSaf. The lead images are difficult to adjust though 'equalize' the grayscale histogram gives a quick over-exposed look that doesn't overlook the small cracks.
Title: Re: MOSAiC news
Post by: Jim Hunt on February 13, 2020, 08:23:29 PM
Via Stefanie Arndt on Twitter:

Today’s afternoon we crossed 85N but couldn’t see the grid line due to heavy snow storms. However, the ridged second-year sea ice and its thick snow layer on top slows us consistently down.

Title: Re: MOSAiC news
Post by: A-Team on February 13, 2020, 09:00:10 PM
If so, the KD is still 3º of latitude away from the PS so 330 km plus some longitude; going will be slower in thicker ice and 15 m/s wind so maybe 1 km/hr or ~336 hrs which is 14 days, a lot later than planned. The KD was held up by Barents waves for a week or more. Leads cannot be assumed to stay open under conditions of compressive stress and pressure ridges are everywhere this year. Both ships will be in the pole hole of most satellites for weeks.

2h @CKatlein
Today we had a short power blackout in the Central Observatory of
MOSAiC, anyways all heaters are running and all systems are warm and
cozy again. Strong winds mostly kept us inside the vessel for the day.
Feb 12
While our supply icebreaker is still 200 miles away making 1-2 knots [2.8 km
hr], we get to experience the first twilight at 87.8° N. The  icedrift takes us
further north with a speed of 0.3 knots [0.6 km/hr]

The buoy array data is already being used, as it should, to study error in various sea ice motion products. Is TL is aware of or using the Sic-Leads product yet?

What we have discovered so far, which is something really new, is how salt from ice gets into snow. We knew that snow can be very salty, but now we have pictures of pockets of brine water in snow. This is important for how snow looks from space. It means that it looks more similar to sea ice.We might think that the ice is getting thicker where, in reality, there's just more (salty) snow on it. Then we have an error in estimates.
Please. This was known and published long ago, just google upward extrusion of brine pockets in maturing sea ice. Yes, this could improve satellite interpretation if only we knew where and how much.
Title: Re: MOSAiC news
Post by: blumenkraft on February 13, 2020, 09:11:19 PM
German biggest public media reported on MOSAIC.

Video at link.

Link >>
Title: Re: MOSAiC news
Post by: A-Team on February 13, 2020, 10:31:21 PM
Decent offering today at FoMo -- a top and bottom DEM of the Mosaic floe and surroundings on youtube which is converted to mp4 below (because the the youtube controller is so annoying in not looping and moving on to unwanted material ... take the spaces out of   /KJf5XOkB5m0 to see).

Nothing is labelled; no distance or height scale or Ice Camp locations are shown. The Polarstern is the dark squiggle. This is not expert use of display software by any means but it is a good start and a breakthrough for FoMo in terms of an interesting post.

It would have been better simply to have done an annotated slide show of the best views rather than the clumsy fly-through. That could include a plan view grayscale of the two DEM data layers. Every frame is angled though. Two screenshots are shown below.

Question is, if the floe is in hydrostatic equilibrium shouldn't the bottom be predictable from the top (apart from density altering inclusions). That is, with a free-floating ice berg, 10% is above the water and 90% below. Here though the overall contiguity of the ice pack and resultant mechanical strength over-ride the buoyant tendencies of individual pieces.
Title: Re: MOSAiC news
Post by: uniquorn on February 13, 2020, 11:36:31 PM
Now, where to put that airstrip?
Here showing most Mosaic IABP buoys that report on the hour. Some report only on the half hour. Inset is nullschool wind isobaric at 1000hpa. Frames are repeated twice to match the hourly buoys. Projection is done using PlotSvalbard in R. Delaunay triangulation in Octave.
Title: Re: MOSAiC news
Post by: A-Team on February 14, 2020, 03:45:37 PM
Given the lack of scales, it is very difficult to make out what is what on the surface and undersides of the Mosaic floe from the youtube provided. In particular, the top priority area is really in front of the bow radar, covered every six hours since 01 Nov 19 but not yet interpreted. Met City etc aren't located; the sensor area is already illuminated by nautical twilight.

This would have been better done as side by side hill-shaded digital elevation models or as user-controlled joy stick as done for surface and basement rocks of some Greenland glaciers. One issue is the very different scales -- the surface heights being about a ninth of underwater keel depths. This alone is a good reason for just providing unadorned grayscale DEMs and letting users take it from there. The attached mp4 reverses colors as the blue is harder to follow than its orange.

The Polarstern, after a prolonged episode of high winds and rapid motion, is now becalmed at 88.0 80.3 at noon on 20-02-14 UTC. The passage across the outer arm of the Chukchi anti-cyclone at about midnight on Feb 14th may have resulted in shearing but that won't show until tomorrow. The bow radar is swinging wildly suggesting that one or more sea ice anchors have come undone in the prolonged 14-15 m/s winds.

Looking ahead to the extreme low pressure in FJL, that is not foreseen to result in extreme winds at the Polarstern's position. A sharp gradient to nearby high pressure is needed for strong winds.

showing most Mosaic IABP buoys
The overlay of 14 days of Sic_Leads to Feb 13th  shows the sea ice motion over the buoy triangulation...
Title: Re: MOSAiC news
Post by: Jim Hunt on February 14, 2020, 05:51:03 PM
In related news:

The Federal Ministry of Education and Research (BMBF) today cancelled the Europe-wide call for tenders for the procurement of a new polar research vessel, Polarstern II, for legal reasons. In times of unresolved climate issues, the research mission of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) can only be fulfilled in the long term with a modern icebreaker. This understanding is also shared by the BMBF. Therefore, we will work intensively with the BMBF to find a solution, which also aims to set up a new award procedure. Among other things, the experiences from the current MOSAiC expedition will be incorporated into the planning process in order to develop an icebreaker that is as future-proof, powerful and sustainable as possible.
Title: Re: MOSAiC news
Post by: A-Team on February 14, 2020, 08:48:09 PM
cancelled procurement of a new polar research vessel, Polarstern II  for legal reasons
Perhaps the language was such that only a German firm could win the contract?

@CKatlein 5h  [20-02-14 13:00 UTC]
Exchange between #MOSAiC leg 2 and 3 was planned for tomorrow (15 Feb).
However the supply icebreaker is still 168 miles away [270 km] and in the last
hour moved less than 1000m. #naturewins

In other words, the KD is practically stuck with 270 km of much thicker ice to cross (though pressure ridges may be the problem this year, not the thermodynamically thickened). At this rate, the KD is 270 hours away (15.4 days) except that's optimistic since the Polarstern drifted 20.4 km away in the last 29 hours.

S1AB today should show the KD's track, except there may not be one if the previous track has sealed over and they are not making a new one. We know more or less where to look from S Arnd's post the other day about crossing 85ºN. Believe that's it's track below 85.1461 80.6331 at 05:47 on 14 Feb 2020. The Polarstern was at 88.0 80.9 at that hour.

If abrupt wind stress gradients matter for disruption of the ice pack, the PS bow radar tomorrow could be interesting in terms of shear.

Technical note: despite the PS not disclosing its position and no S1AB coverage, when there is a break from in the latitude decimal, it means the ship crossed 87.9000 and 88.0000 parallels, though in the latter instance, the PS didn't transmit its weather for 3 hours.

88.0   84.8 20-02-13 08:00   13  110    -28.9
87.9   85.3 20-02-13 05:00   13  110    -28.8

87.9   88.3 20-02-12 03:00    9  110    -31.9
87.8   88.4 20-02-12 02:00    9  110    -31.7
Title: Re: MOSAiC news
Post by: uniquorn on February 15, 2020, 12:30:14 AM
Title: Re: MOSAiC news
Post by: Jim Hunt on February 15, 2020, 11:38:08 AM
I haven't got time to make a video. Storm Dennis has arrived!

However I believe this currently reveals KD top left and PS bottom right:
Title: Re: MOSAiC news
Post by: A-Team on February 15, 2020, 01:32:16 PM
KD yellow circle, PS magenta circle
Looks about right. The KD may be aiming east of the PS in order to catch the transpolar drift (instead of fighting it). If the ships are drifting in opposite directions, the KD could struggle all day with the ice but end up farther away from the Polarstern than when it started.
Title: Re: MOSAiC news
Post by: psymmo7 on February 15, 2020, 10:30:28 PM
If anyone is good in Danish - then Rasmus Tonboe is reporting from the Kapitan Dranitsyn at this site.
Apparently  the ship passed through a snowstorm last Sunday (9th Feb) picture attached
Title: Re: MOSAiC news
Post by: A-Team on February 16, 2020, 11:30:02 AM
If anyone is good in Danish
So bizarre: providing routine blog text only as a png image. It just takes a second though to run it through free online Danish OCR ( and then google-translate.

"Tomorrow there is a general clean-up and a single trip out on the ice to drill cores in the EMIRAD measurement area near the ship.

The other morning, when I was with the chemistry team at the "dark site" and taking samples, I saw a slight light to the south on the horizon. "Dark site" is so far from the ship that there is no light pollution, and therefore you can see even the faintest shades of light.

I took a picture of the horizon with my mobile camera, but when I got home and looked at the picture, it looked like I had turned off the phone. It was completely black and there was no hint of light. The sun is still far below the horizon, and it's not even twilight, but we've got the moon back and it gives some light when we're out.

Last weekend we had a strong low pressure with strong winds and temperature fluctuations. Saturday morning started with blizzard and 20 m / s and temperature of about -12 degrees.
During the day the wind subsided while the temperature dropped to -38 degrees towards evening.

The captain had forbidden going out on the ice in the morning, and I spent most of the day in the "cold lab" working with ice samples from our measuring range. "Cold lab" is a container on the back deck which is designed for laboratory. The laboratory has -15 degrees, so you can work with your snow and ice samples without melting. Compared to the outside temperature, it feels warm in the lab.

I am working on mapping the composition of the ice cream; the size and distribution of air bubbles and the distribution of salt in the ice. It affects what we measure with our satellite instruments, which is why it is important to be able to develop computer models.

There is still some wind, but the temperature was only -15 degrees when we were out digging our instruments out of the drivers."

R Tonboe has an English language twitter site but has not posted anything since 27 Nov 19. His interests with Mosaics are remote sensing, ice team and ESA radiometer. His 2019-20 papers:

Version 2 of the EUMETSAT OSI SAF and ESA CCI sea-ice concentration climate data records

In situ observed relationships between snow and ice surface skin temperatures and 2 m air temperatures in the Arctic

Estimating the snow depth, the snow–ice interface temperature, and the effective temperature of Arctic sea ice using Advanced Microwave Scanning

Will low primary production rates in the Amundsen Basin (Arctic Ocean) remain low in a future ice-free setting, and what governs this production?

Estimating sea ice parameters

Satellite passive microwave sea-ice concentration data set intercomparison: closed ice and ship-based observations

SMOS-HR: A high resolution L-band passive radiometer for Earth science and applications
The Kapitan Dranitsyn is not making much forward motion today. It is visible on the animation up to about 06:00 on Feb 16th. It is a challenge to meet up not only because of the ice but because the  two ships experience different (and changing) drift trajectories.
Title: Re: MOSAiC news
Post by: colding on February 16, 2020, 01:25:53 PM
So bizarre: providing routine blog text only as a png image. It just takes a second though to run it through free online Danish OCR ( and then google-translate.

I've sent a short mail to DMI asking them to please publish the diary in English or at least as text only.
Title: Re: MOSAiC news
Post by: A-Team on February 16, 2020, 08:37:59 PM
publish diary as text
The concept: a hardy explorer pecking out a diary on a courier typewriter like in days of olde? Nansen had electric lights already on the Fram. The PS has two bars, a sauna and a swimming pool.

Meanwhile, the Kapitan Dranitsyn has advanced 34.7 km in the last 21 hours. Not all of it was in the direction of the Polarstern,  only about 14 km. The zigzag route yields an effective linear approach speed of 16 km/day which means 18 more days till docking with the Polarstern, say early March. And delays will be similar or worse for those returning to Tromsø.

Because the ice is drifting, getting to the Polarstern is like crossing a river: start quite a ways upstream, not right across. That's not an easy calculation though, a lot of imponderables:

If the KD is moving at x(t) m/s at bearing a(t) under steam but the ice around it is drifting y(t) m/s at bearing b(t), how many days does it take, given the GFS wind forecast f(t) to reach the PS which is not under steam but has been drifting at z(t) m/s at bearing c(t)? Nansen's rule of thumb was the icepack drifts at 2% of the wind speed at an angle of 20-40% to it from the Coriolis effect.

The KD is probably not doing the math here but instead just seeking a pragmatic route that avoids thickest pressure ridges. Those could be more prevalent than in the past because ice pack motion has gotten measurably worse.

Meanwhile, the current Polarstern scientific team is still deploying equipment 4.5 months after mooring. These instruments have to installed far from the lights of the ship which would disturb what they are trying to measure. The location has not been disclosed. The acronyms ITBOB, ENVI-POPE and AZFP stand for:

-- Ice-tethered bio-optical properties and radiation
-- Platform  cluster for Optical,  Physical and Ecological sensors
-- Acoustic Zooplankton Fish Profiler
Title: Re: MOSAiC news
Post by: A-Team on February 17, 2020, 05:05:42 PM
The KD has been making better progress north, aided by ice pack drift. A long section of track is outlined in yellow in the gif below, needs click. Meanwhile the Polarstern is drifting west. The extreme low pressure system coming to the Barents will have little effect on winds which will remain sub-gale force.
Title: Re: MOSAiC news
Post by: uniquorn on February 18, 2020, 01:27:40 PM
New Snowbuoy 2020S99. ( A touch south east of p207.
Title: Re: MOSAiC news
Post by: A-Team on February 18, 2020, 03:09:25 PM
New snowbuoy 2020S99. A touch south east of p207.
"This buoy replaces 2019S92, which was crashed during a ridging event." Does that mean inactive 82, 83, 85, 88-91, 95, 97, 98 met similar fates?

On the inactive snowbuoy setting, they only show 2019S95 which was operative for 6 days at the M7 site co-deployed with 2019O7 and 2019T71:

2019S79   86.00   119.17   07.10.19-28.11.19 (52)    
2019S80   85.96   122.71   08.10.19-02.11.19 (26)
2019S92   86.04   117.73   07.10.19-26.11.19 (50)
2019S95   84.62   133.29   11.10.19-17.10.19 (6)

2019S81   88.25   85.17   07.10.19
2019S84   86.49   109.32   07.10.19
2019S86   88.16   69.44   10.10.19       
2019S87   88.40   81.98   09.10.19       
2019S93   88.04   80.39   07.10.19       
2019S94   88.20   74.00   10.10.19    
2019S96   88.08   77.50   29.10.19
2020S99   87.96   75.37   10.02.20

"2019S92 was at the L1 site, co-deployed with 2019R9, 2019W4, 2019I1, 2019F1, 2019T67, one ASFS, one MARC" so we could determine from S92 where the mysterious L1 site is relative to the Polarstern.

Ditto 2019S93 which was co-deployed at L2 with 2019R8, 2019W2, 2019I2, 2019T63, 2019T65, 2019F2, ASFS, MARC

The ASFS (Shure's sonic atmo sled, see above) that "got eaten by a pressure ridge" was at L3. They got that unburied on 15 Feb 2020 according to FoMo but it is not yet functioning. At the L1-3 sites, they are trying to do air, ice, ocean in coordination so it hurts to have a major component down.

2019S94 was co-deployed at L3 with 2019M30, 2019W3, 2019T70, 2019I3, 2019F3, ASFS, UNMANNED-ICE-PRIC

Today at 03:00 the L2 site was at lat lon 88.0420  80.3936 whereas the PS was at 88.1  77.9 per awiMET which is 11.4 km away. The PS can be located slightly better using RAMMB (at 03:27 at 88.074  77.85) which is 10.21 km away but the last known precise location for the PS from S1AB was on 2020 02 02 at 05:46 87.3446   95.4993.

Given a similar calculation for L1 and L3, the three lines could be visualized on GoogEarth where they would not quite radiate out consistently from the PS location because of error but be very close to displaying the overall configuration. Following the L123 triangle over time would show rotation.

Although difficult to see on Sentinel, the KD is still 263 km away from the Polarstern but winds remain moderate (despite the nearby 953 hPa low) and ice pack motion is favorable for trajectory convergence. It's not unusual for ships and explorers get caught on a treadmill where despite a whole day's effort, they make no progress towards their goal. That's not happening here (to the extent the KD can make headway).
Title: Re: MOSAiC news
Post by: paolo on February 18, 2020, 04:49:48 PM
Earthquake M 5.2 - North of Svalbard
•   2020-02-18 07:29:39 (UTC)
•   85.740°N 22.699°E
•   10.0 km depth
Title: Re: MOSAiC news
Post by: uniquorn on February 18, 2020, 05:58:23 PM
Hopefully PS and KD are ok in deep water.
Given a similar calculation for L1 and L3
Tbuoy gps appear to be struggling somewhat. Wbuoys didn't last long. I and Fbuoys??
An equal combination of R8(L2), R9(L1) and S94(L3) gives the estimated PS location below. It looks a bit too far west. I'll run it back to known location points, it could work.

added jan5-15 as a test. Red dots are S1 calculated PS locations (timing not checked)
Title: Re: MOSAiC news
Post by: A-Team on February 18, 2020, 08:52:21 PM
Earthquake M 5.2 - North of Svalbard  2020-02-18   85.740°N 22.699°
This site is called the Sparsely Magmatic Zone (SMZ) of the Gakkel Ridge. Only one large volcanic center at 19° E has been noted over the entire extent of this segment.

JD calculated years ago on another forum that even when the volcano field erupted a bit east in the Eastern Volcanic Zone (EVZ), the amount of heat released was utterly inconsequential as far as melting Arctic Ocean ice or even for turbulent disruption of the salinity and thermal layers.

Did the 1999 earthquake swarm on Gakkel Ridge open a volcanic conduit?

In 1999, a seismic swarm of 237 teleseismically recorded events marked a submarine eruption along the Arctic Gakkel Ridge, later on also analyzed by sonar, bathymetric, hydrothermal, and local seismic studies... We find event locations scattered around 85°35′ N and 85° E at the southern rift wall and inside the rift valley of the Gakkel Ridge. seismic station on FJL 35 year earthquake record
Title: Re: MOSAiC news
Post by: A-Team on February 18, 2020, 09:45:29 PM
FoMo released a new map of the area around the ship today! It is reproduced below as their enlarged view 1696 x 1620 pixels (at which text is readable) so needs a click and large device screen. A dozen or two acronyms are not explained in the Legend.

No map scale is provided; however the PS measures 118 m, indicating the large squares are 500 m and the dotted smaller squares 100m.

There is no labelled lat lon graticule and north is not indicated as it varies with drift but is more or less at the top, going by recent S1AB with graticules. A near-vertical line of the grid system runs through something called nav(0,0) but the horizontal lines have no special relationship to nav(0,0). The grid appears set to be parallel / perpendicular to the Polarstern's bow-stern axis, which makes some sense the ice camp is accessed off the starboard side.

The map only includes 1000 pixels of the area mapped daily by the ice radar which points out 1310 pixels (2.5 km) from the bridge. Oddly an overlay of the bow radar does not have any features matching the runway.

The bluish-white base map appears to be heights determined by the laser altimeter patched together from helicopter overflights on different days. No scale (z axis) is provided but generally white indicates pressure ridges and surface ice jumbles. Some of these represent summer floe-building collisions and were already present at mooring back on Oct 4th; others are newer (not indicated despite symbols for leads and ridges in the legend).

Starting at the top left, the text overlays can be assigned png mouse-over x,y pixel coordinates and analyzed in a sortable database, sampler below and full csv attached.

The Remote Sensing site (RS on the map) acknowledged the loss of three instruments yesterday: KuKa, X-Scat and Elbara (a passive L-band 1.4 GHz smos-type radiometer). No spare parts are available on board, none are coming with the KD and implausibly by air on leg 4. (L Kaleschke's research involves Elbara; he is on the KD.)

No explanation has been given for three devices all failing (unsuitable connectors? power supply is from the PS). UWBRAD, an ultra-wideband 0.5–2GHz radiometer, is still working as is the SSMI radiometer (19, 37, 89 GHz) and the GNSS-R.

This is a major loss for remote sensing improvement. No summary of total trip up-time been provided. J Stroeve wrote about problems back on Dec 1st, tweeting "Our radar is once again connected to the power while some instruments are still awaiting connection."

The map term GNSS occurs in three places. Probably GNSS-R was intended for reflected GNSS signals from snow/ice  which relate to ice thickness, altimetry and scatterometry of various types of satellite GPS-like signals. pg 87

Technical inspection of the new map establish it as a disturbingly amateurish product given its importance to operation planning and communications. Surely a shipload of scientists on a $150,000,000 budget stuck on board for days at a time by weather could muster up someone onboard or ashore with basic graphics skills (such as editable layer compositing). They will need a journal-quality map later ... and this is not it.
Title: Re: MOSAiC news
Post by: uniquorn on February 19, 2020, 12:34:50 PM
PS continued drifting north west. With the current cyclone, perhaps the two teams will share the most northerly location in a few days time.
updated below
Title: Re: MOSAiC news
Post by: A-Team on February 19, 2020, 12:40:27 PM
@CKatlein 6h Finally our resupply icebreaker is so much delayed, that Polarstern has reopened the bar! #MOSAiC
That storm coming up from the Caribbean has morphed into a strong cyclone that is now predicted to drift across the FJL line into the Arctic basin and past close to the Polarstern as it gradually dissipates, even as a new system comes in.

This will significantly complicate the rendezvous of the KD and Polarstern as their drifts will be affected differently. At these stronger wind stress gradients, the Ice Camp experimental area may have more problems with pressure ridges, opening leads and shear lines. So far ice motion has been limited to shears on the periphery. (Much higher winds occurred earlier on the drift: 20-02-01 20 m/s.)

The KD appears to be at 86.4771  89.8613 at 05:55 this morning though the track on Sentinel is ambiguous and Rammb is cloudy. If so, with the Polarstern at 88.25  74.4 and moving rapidly west, the two ships are separated by 211 km with a rendezvous maybe ten days off.

Temperatures have already risen by 15º and winds are quite a bit stronger than GFS had foreseen yesterday (or rather, the discrepancy between observed shipboard winds and GFS winds has widened). These temperatures per se are still too cold and transient to melt ice but the Kara/Barents/FJL ice will be greatly dispersed and disrupted.

   Lat  Long  YY-MM-DD  UTC     Wind       T(C)   hPa      GFS
  88.3   71.6 20-02-19 19:00   14  110    -13.1  978.3
  88.3   71.8 20-02-19 18:00   13  110    -13.3  978.8  10.5  120
  88.3   72.0 20-02-19 17:00   13  100    -13.6  979.1
  88.3   72.2 20-02-19 16:00   13  100    -14.0  979.5
  88.3   72.4 20-02-19 15:00   14  100    -14.3  979.9  11.0  115
  88.3   72.6 20-02-19 14:00   14  100    -14.6  980.3
  88.3   72.8 20-02-19 13:00   14  100    -14.7  980.6
  88.3   73.0 20-02-19 12:00   15  110    -14.8  980.8  12.7  115
  88.2   73.5 20-02-19 10:00   16  110    -14.3  981.4
  88.2   73.7 20-02-19 09:00   16  110    -13.6  981.5  12.8  115
  88.2   73.9 20-02-19 08:00   16  110    -13.2  982.1
  88.2   74.4 20-02-19 06:00   16  100    -12.7  982.5  13.9  115
  88.2   74.6 20-02-19 05:00   14  110    -12.9  983.4
  88.2   74.8 20-02-19 04:00   15  100    -13.4  983.7
  88.2   75.0 20-02-19 03:00   14  100    -13.7  984.6  12.1  100
  88.2   75.2 20-02-19 02:00   12  100    -13.9  985.2
  88.2   75.4 20-02-19 01:00   12  110    -13.9  985.6
  88.2   75.5 20-02-19 00:00   12  110    -13.6  986.0  10.1  125 most recent bow radar
  88.2   75.7 20-02-18 23:00   12  110    -12.9  986.3
  88.2   75.8 20-02-18 22:00   12  110    -13.2  986.5
  88.2   75.9 20-02-18 21:00   12  110    -13.4  986.7  10.3  115
  88.2   76.1 20-02-18 20:00   13  110    -13.4  986.7
  88.1   76.3 20-02-18 18:00   11  110    -14.3  986.9  10.1  115
  88.1   76.4 20-02-18 17:00   11  110    -15.4  987.2
Title: Re: MOSAiC news
Post by: uniquorn on February 20, 2020, 12:04:14 PM
Longitude dropping quickly as they continued north west yesterday.
updated below
Title: Re: MOSAiC news
Post by: A-Team on February 20, 2020, 08:28:08 PM
The Polarstern continues to drift rapidly north and west in high winds and driving snow associated with the warm wet cyclone moving slowly across the Arctic Basin from FJL. Staff is confined to the ship under these conditions which will persist for the next couple of days.

FoMo is reporting hazardous ice motion (creating snow-covered open water) but these leads are not yet showing on the PS bow radar. These will worsen because of the ice pack cannot follow the sharp curvature of the wind. Meanwhile on-ice instruments may need repair but cannot be serviced. On Feb 13th, the whole Central Observatory experienced a brief (unexplained) power blackout.

The KD is not showing on RAMMB because of cloud cover though the PS has been visible at times. Its location is not known because it does not post a weather report nor turn on its beacon. It is seeing similar weather to the PS and drifting along the same streamline. It may be possible to pick up on its Sentinel track from yesterday and find a current position.

Uniq provides the AMSR2 view on the freeze forum today #929:
The Polarstern continues to fly north and west under the cyclone. It is visible on RAMMB but the KD is not (nor does it provide its location).

Iain provides a WorldView visible animation of the CAA Perry ice bridge and compared to earlier years #925. That area has been monitored with an observatory of moorings for years.


The Barrow Strait Real Time Observatory: Under-ice Monitoring in the Canadian High Arctic Nov 2017

These can also be visualized using the new SIC lead product from L Kaleschke, the last 60 days below. Unfortunately it does not going any farther west than shown. He is on the KD and seemingly unreachable.
Title: Re: MOSAiC news
Post by: johnm33 on February 20, 2020, 11:32:20 PM
I find it particularly interesting that the leads and apparent wave structures move through the ice rather than with it, the PS' slow progress is the best indication of this I've seen. The emergent double features indicates an acceleration?
Title: Re: MOSAiC news
Post by: A-Team on February 21, 2020, 01:03:21 PM
leads and apparent wave structures move through the ice rather than with it
OsiSaf gives another view, more along the lines of wind-induced. Ascat over 81 days gives yet another perspective, of smooth flow.

The Polarstern will continue to move rapidly poleward and towards the Fram this week under the influence of cyclones passing over Greenland. If it does reach the pole, it may be stuck in that area for quite a while as that ice is off the transpolar drift in most years.

The ship is currently at record lat lon of 88.5 66.2 on 20-02-21 at 15:00 with warm persistent winds in the 13 m/s range which are borderline for outdoor work. The Kapitan Dranitsyn is 184.1 km (still a week away) as of noon today at 87.06 89.1, with progress reported slowed by the same storm. Neither ship will be visible on Sentinel over the next weeks though the wavy KD track is available at 04:50 this morning.
Title: Re: MOSAiC news
Post by: uniquorn on February 21, 2020, 01:19:29 PM
drift as noted above - see below
Title: Re: MOSAiC news
Post by: uniquorn on February 22, 2020, 11:17:33 AM
Verifying those large low concentration leads north of Greenland., feb21-22, Kaleschke sic leads inset. ctr

drift update. Below 45E they start drifting away from the pole. At the recent rate of ~3degrees/day that's maybe 5-6days away. KD might just make it.
Title: Re: MOSAiC news
Post by: A-Team on February 22, 2020, 06:20:13 PM
A steady tailwind bearing for 56 hours produced the incredible straight drift of the proxy buoys for the Polarstern seen in Uniq's #635 animation above. Chasing down the stats, the ice pack moved at 2.1% the speed of the 1000 hPa wind (confirming what 'they' have been saying for years).

This wouldn't be possible without unresisting exits for the ice such as Fram, Nares and SV-FJL gap because the ice pack cannot compress further against land. (Over-rafting pressure ridges provide too much pushback when the ice is thick.)

Data from awiMet should someone wish to refine the estimate by providing the std error:
wind m/s,bearing 12,110 12,110 12,110 11,110 11,110 12,110 12,120 13,110 12,110 12,110 11,110 12,100 12,100 12,110 13,110 14,110 14,110 13,110 13,100 13,100 14,100 14,100 14,100 15,110 16,110 16,110 16,110 16,110 16,100 14,110 15,100 14,100 12,100 12,110 12,110 12,110 12,110 12,110 13,110 11,110 11,110 9,110 10,110 10,100 10,110 11,100 10,90 9,90 9,90 8,90 9,90 8,90 

Both ImageJ and Gimp offer image enhancement by convolution kernels, both canned (Process -> shadows) and roll-your-own DIY. They have a very beneficial effect on the Kaleschke SIC lead product (and downstream overlays), enhancing lead visualization without blowing up the grayish white interstitial background like linear contrast change, local adaptive (clahe) or histogram equalization.

To the extend the leads are anisotropic -- and they will be from TPD or during passage of a cyclone -- the choice of convolution 'direction' matters. The mp4 below used 'northeast'. No rocket science is involved automating out from the canned convolution to converge onto a quasi-optimal element of GL(3,R) wrt to frame average and that extends to a rolling window of GFS winds.

While some people are twittering from the KD, others are not. Kaleschke did not have time to describe productions methods but it is clear from Uniq's remarkable match-up in#635 of microwave leads with WorldView infrared that SIC leads just takes a longer radar wavelength approach to heat escaping through the ice. The images can't help but agree.

In other words, low Ghz radar meets up with long wavelength infrared in the electromagnetic spectrum, the difference being WV infrared is at the mercy of cloud cover while low Ghz sees through them better (in winter). It benefits from processing to darken warmer regions (ie the leads). We don't know what processing steps were taken but clearly they can be improved for the purpose of overlays on GFS weather,  Ascat scatterometry etc etc which don't see the leads but have other, complementary strengths.

The tripods have proven a planning and operational fiasco. Just drill through the ice, freeze in some 5 m fiberglass poles with no guy wires, hang slack electric and data cables off them, your pressure ridge problems are over. And where did Mosaic get their no-go snowmobiles, out of a museum?
Title: Re: MOSAiC news
Post by: uniquorn on February 23, 2020, 11:43:40 AM
Thanks for those calculations. Here looking a little closer at the direction change to close to due west. Drift speed picking up again after the turn.
edit: updated, p207 grazing along the 88.6 line. Wind fairly constant.
Title: Re: MOSAiC news
Post by: blumenkraft on February 24, 2020, 02:50:40 PM
From the Polarstern-Blog

A successful ROV day

Link >>
Title: Re: MOSAiC news
Post by: A-Team on February 24, 2020, 05:18:18 PM
Although RAMMB has been showing the Kapitan Dranitsin closing in on the rapidly drifting Polarstern by the end of February, visibility from above is often obscured by clouds. It now appears that the KD is stuck in the thicker colder ice nearer the pole (as predicted above), still 100 km from the PS.

That is not an impossible distance for helicopter exchange of leg2/leg3 scientists and for transfer of experimental matériel but flight conditions are currently far from acceptable: gale-force 15m/s at 15:00 at 88.6 53.3 on Feb 24th. The KD was able to un-stick itself returning last time by shifting fuel from port to starboard tanks.

Follow-Mosaic speaks of multiple Twin Otter landings maybe being feasible on unprepared airstrips at both the KD and PS sites but that potentially doubles down on catastrophic risks without resolving the underlying issues.

The KD was supposed to bring extra fuel to the PS but now it seems if the KD does that, it won't have enough fuel of its own to get back to Tromsø, so a relief icebreaker for the relief icebreaker has to be considered.

Both ships are provisioned for up to a year so scientific work can continue at least at the PS. Despite conditions, the ROV has been able to log over 80 km of undersea ice mapping, even photographing that ringed seal investigating another misaligned thermistor cable. (Because they couldn't find a suitable 'thermodynamic' floe back in October, the PS moored on a pressure ridge jumble.)

Something has gone wrong at the ice radar archive. The heavy white scale bar is now lying over the image, causing loss of data. This bar should never have been placed here as ample black space was available in the masked region. It has never been clear whether this represented compass NS; better had digital lat, lon and ship axis bearing been placed above a km length scale bar. All that was provided on the device screen but cropped out. The ice pack (and the embedded PS) may be rotating more than anticipated.

Meanwhile the PS is moving west at an extraordinary rate of 0.4 ºlon/hr, bringing it into an extreme fracturing zone caused by cyclones barreling in through the SV-FJL gap instead of the usual winter path up the Fram. This pattern has greatly enlarged the Fram intake funnel out beyond the north pole (as noted here last week), with even the Lincoln Sea ice being drawn in. The Polarstern will be located just to the right of the pole hole (ie 50º at nullschool) later this afternoon.
Title: Re: MOSAiC news
Post by: blumenkraft on February 24, 2020, 06:58:34 PM
From the MOSAIC web-app:

Severe ice conditions in the Arctic currently delay the approach of
the Russian supply vessel Kapitan Dranitsyn towards the
Polarstern. Ideally, the vessel should reach Polarstern in the coming
days, but weather and ice conditions are still difficult. That dense
winter pack ice could delay the exchange phases between legs two
and three was part of the expedition planning from the beginning
and is thus not a surprising situation. Already in the planning phase
we took into account that the supply vessel may not be able to
reach Polarstern during the polar night. In such case it was planned
to exchange personnel and cargo via the on-board helicopters of
Polarstern. However, there are no suitable flight weather conditions
at the moment. In parallel the feasibility of operating two polar Twir
Otter aircraft is evaluated at the moment to ensure a faster
exchange. Under certain conditions a Twin Otter is able to land on
unprepared sea ice next to Kapitan Dranitsyn, but needs a safe
landing strip at Polarstern and also flight weather conditions.
Additionally, the possibility of support by another icebreaker is
evaluated, that could steam towards Kapitan Dranitsyn to provide
additional fuel on the way back when the same ice conditions will
be encountered. In the meantime, scientists and crew onboard both
vessels remain patient and wait for easing conditions in the next
days. But most importantly: safety is not affected and there are
enough supplies on both ships. The scientific activities continue on
board Polarstern and are not affected by the situation. The picture
of the day shows that the atmosphere on board Dranitsyn is good
despite the delay. It is not clear yet when the exchange can be
completely finished and which additional delays will arise for the
future exchanges of scientific teams and the ship's crew. The
options are well prepared and also discussed with the participants
of leg 4 of the expedition. The necessary patience and flexibility
needed by everyone to plan expeditions in unknown territory and
under unknown weather conditions could not be described better as
summed up by Berthold Brecht: "Ay, make yourself a plan, they need
you at the top, then make yourself a second plan, then let the whole
thing drop."
Title: Re: MOSAiC news
Post by: A-Team on February 24, 2020, 09:08:20 PM
The KD has gotten itself stuck and unstuck multiple times before. The question here is if they could, would they continue north to the Polarstern without enough fuel for the return trip in thick ice? They could perfectly well moor alongside the Polarstern and await the melt season.

This would be better for the scientific program. The KD itself does not carry the Pistenbullys necessary to plow an 1800 m wheeled airplane runway but an opportunity might arise for staff and crew exchanges.

If the KD cannot get itself unstuck, it might take several months to lease a heavy duty nuclear icebreaker that could escort the KD to the Polarstern or more likely back home. Most capable icebreakers are contracted out months or even years in advance; the KD is not in an emergency situation.

In the last few years the Kapitan Dranitsyn has been modified as a passenger vessel, with 49 outside cabins for 100 passengers. Public accommodation includes spacious lounges, bars, a heated swimming pool, gym, sauna, library and a small hospital. wiki
Air drops for both the KD and PS could bring in lighter essentials; these are a whole lot safer than multiple landings on ungroomed airstrips which could bring on emergencies for which there is no response.

One option not yet mentioned is for the more capable icebreaker Polarstern to fire up its engines, go free up the KD and perhaps escort it south a bit, do the exchanges, and return to wherever its current position has drifted. This would leave the power (and data collection) off for a prolonged period at deployment sites so more likely the many tons of irreplaceable scientific equipment would have to pulled in first.

This would entail an enormous amount of de-installation and re-installation work in high wind chill (but not dark) and seriously undermine the scientific mission. Alternatively a skeleton crew and generator could be left in a lifeboat equipped as shelter to keep things repaired and going.
Title: Re: MOSAiC news
Post by: uniquorn on February 24, 2020, 09:51:21 PM
Latest rammb view of KD apparently ceasing northward movement and drifting west. Will be interesting to see how the two drift paths compare (maybe there is a buoy nearby..)
heavy contrast
Title: Re: MOSAiC news
Post by: A-Team on February 24, 2020, 11:22:41 PM
On Rammb, the 60 frame time series is needed, color the dot pairs you're sure of. The PS also responded to a change in wind bearing around the same time. The longitude of the KD can be estimated easily enough but latitude retrieval depends on including the outer 85º circle in the time series (on the extremely flighty Rammb display) so that the number of pixels to 87.5º can be measured to proportion the KD's location.

Since GFS nullschool gives the same wind speed and direction wherever you click (within reason), the KD and PS will have the same drift as long as neither is under steam. The short cut is just to count pixels between the two Rammb dots over time: if constant, the KD is still stuck.

It's interesting to read people onboard the PS are hoping the KD can get closer, needn't actually get to the PS. Presumably that makes multiple round trips a lot easier for the helicopters. The PS has two and the KD a larger one. Closer though means more problematic for the KD crew and leg2 scientists in terms of returning home, though possibly the outbound broken swath could be re-used.

Update: persistent strong winds over the last 36 hours are pushing the local icepack rapidly west, taking the Polarstern with it at a record clip of 0.4º lon/hr. More of the same is forecast for the  next 72 hours with an increasing southerly component.  The KD is no longer on a streamline to the PS but rather on a parallel one heading to the the FJL gap.
This will leave the PS at perhaps 88.3 20.0 by the first of March, leaving the ship 857 km from its 15 Oct 2020 final destination in near-prime transpolar drift position that could end the mission by the first of June some 4 1/2 months early.
Title: Re: MOSAiC news
Post by: uniquorn on February 25, 2020, 12:13:43 PM
The PS also responded to a change in wind bearing around the same time
Agreed, I should have taken account of that.

drift update. Mostly west, edging south. With the present forecast it's likely that feb23 ~20:45 was as far north as they go. An accurate PS location is not disclosed but here is p207 data. (recent data attached as txt)
p207,2020-02-23 20:30:25,88.5921,57.8164
p207,2020-02-23 21:00:26,88.5921,57.6921
Title: Re: MOSAiC news
Post by: Jim Hunt on February 25, 2020, 01:15:27 PM
Via Stefan Hendricks on Twitter (, a new discussion paper:

The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf

We show, using a Lagrangian tracking tool and a thermodynamic sea ice model, that the MOSAiC floe carrying the Central Observatory (CO) formed in a polynya event north of the New Siberian Islands at the beginning of December 2018. The results further indicate that sea ice in the vicinity of the CO (< 40 km distance) was younger and 36 % thinner than the surrounding ice with potential consequences for ice dynamics and momentum and heat transfer between ocean and atmosphere.
Title: Re: MOSAiC news
Post by: A-Team on February 25, 2020, 05:48:55 PM
We're getting mixed signals at the moment: is the KD stuck or just proceeding slowly, has it already exhausted so much fuel it cannot get back to Norway, is another icebreaker passing by in the vicinity capable of refueling it? Both bloggers onboard have gone silent.

The Rammb frames on which both ships are visible do not show the KD closing on the PS. That is consistent with either the KD being stuck or just making very slow progress.

The "Kapitan Dranitsyn" supply icebreaker is barely making any progress. "The mood on board the Polarstern is very tense," said Chief Scientist Professor Christian Haas. "There is uncertainty as to how to proceed. The colleagues are disappointed that there is no foreseeable return soon.

But since mid-December the sea ice in the winter arctic has grown steadily, it is up to 160 centimeters thick and provided with many dense press ice ridges by stormy winds. Open and thin jobs are rare. And so the KD is struggling slowly - with such high energy consumption that the fuel will not be enough to return to Norway. 

Ideally the KD will reach PS in the next few days, the expedition blog led by the Bremerhaven Alfred Wegener Institute (AWI) says: "However, the weather and ice conditions are still adverse."

Markus Rex expects the KD to reach Polarstern in the next few days. It is only 50 nautical miles away.  She had made good progress in the past 24 hours. Rex says planes are also available in Canada. But better weather is also needed for their use.

Chief Christian Haas says  it was presumptuous to believe that in mid-February a conventionally operated ship would get to the central Arctic. There is no experience with it, not even with the &qu