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uniquorn

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Re: MOSAiC news
« Reply #150 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.
https://www.sailwx.info/shiptrack/shipdump.phtml?call=DBLK

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,

Quote
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.
« Last Edit: October 20, 2019, 10:56:49 PM by uniquorn »

A-Team

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Re: MOSAiC news
« Reply #151 on: October 21, 2019, 12:34:44 PM »
Quote
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.

Quote
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

https://www.sailwx.info/shiptrack/shipdump.phtml?call=DBLK
https://www.sailwx.info/shiptrack/shipdump.phtml?call=UCKZ
https://www.sailwx.info/shiptrack/shipdump.phtml?call=/////

Quote
This website is owned and published by Mobile Geographics LLC, 8015 28th Ave NW, Seattle, Washington 98117. Contact webmaster @ sailwx.info. All advertising is supplied by Google Adwords; to advertise on this site, visit http://adwords.google.com/. Adwords Direct purchase is available.

Most of the information presented comes via a single, fallible pipeline with no redundancy. Data stream is processed automatically, without any human oversight, automatic quality control, or "sanity checking". This website does not meet the standards to be expected of a mission-critical meteorological or navigation resource.

You are permitted to use this site only for entertainment. Accuracy and timeliness of information are specifically not guaranteed. Use of this website for purposes of navigation is prohibited.
« Last Edit: October 21, 2019, 03:05:09 PM by A-Team »

A-Team

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Re: MOSAiC news
« Reply #152 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.
« Last Edit: October 21, 2019, 06:55:53 PM by A-Team »

Niall Dollard

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Re: MOSAiC news
« Reply #153 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.


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Re: MOSAiC news
« Reply #154 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.
« Last Edit: October 22, 2019, 12:49:49 AM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #155 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 https://forum.arctic-sea-ice.net/index.php/topic,2417.msg233858.html#msg233858

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Re: MOSAiC news
« Reply #156 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.

https://earth.nullschool.net/#2019/10/22/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/21/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/20/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/18/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/17/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/16/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/15/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/14/1200Z/wind/surface/level/orthographic=-45,90.0,1000/loc=131.300,85.300
https://earth.nullschool.net/#2019/10/13/1200Z/wind/surface/level/orthographic=-45,90.0,1000/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



« Last Edit: October 23, 2019, 03:17:38 AM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #157 on: October 22, 2019, 11:41:41 PM »
Complete guess ;) overlaid onto S1A_EW_GRDM_1SDH_20191021T042433_A9EB_N_1.final with poor scaling.

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Re: MOSAiC news
« Reply #158 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.
« Last Edit: October 23, 2019, 12:50:29 AM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #159 on: October 23, 2019, 12:48:35 AM »
The scaling needs some work I think  :-\

psymmo7

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Re: MOSAiC news
« Reply #160 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.

NotaDenier

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Re: MOSAiC news
« Reply #161 on: October 23, 2019, 10:33:16 AM »
How MOSIAC selected the floe.

https://www.bbc.com/future/article/20191018-the-problem-of-thinning-arctic-sea-ice?ocid=global_future_rss

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

uniquorn

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Re: MOSAiC news
« Reply #162 on: October 23, 2019, 12:24:33 PM »
Quote
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.

Quote
have turned out to be less than half that
Yesterday's image from https://follow.mosaic-expedition.org/   Ridged ice showing the thickness in that location.

added polarstern temperatures
« Last Edit: October 23, 2019, 12:58:38 PM by uniquorn »

Phil.

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Re: MOSAiC news
« Reply #163 on: October 23, 2019, 02:46:09 PM »
How MOSIAC selected the floe.

https://www.bbc.com/future/article/20191018-the-problem-of-thinning-arctic-sea-ice?ocid=global_future_rss

“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?

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Re: MOSAiC news
« Reply #164 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.

https://www.bbc.com/future/article/20191014-climate-change-arctic-expedition-finds-itself-on-thin-ice

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

Quote
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.

https://blogs.agu.org/thefield/ 5-part blog by M Shupe 05 Oct latest
https://twitter.com/hashtag/ARMMOSAiC?src=hash
https://twitter.com/MOSAiCArctic
https://twitter.com/ciresnews?lang=en
https://www.mosaic-expedition.org/expedition/ice-camp/
https://blogs.helmholtz.de/polarstern/en/

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.

https://seaice.uni-bremen.de/data/smos_smap/png/north/2019/20191019_north_mix_sit_v205.png


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
« Last Edit: October 23, 2019, 09:00:00 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #165 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
« Last Edit: October 24, 2019, 12:15:06 AM by uniquorn »

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Re: MOSAiC news
« Reply #166 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

https://www.nasa.gov/feature/goddard/2019/laser-precision-nasa-flights-satellite-align-over-sea-ice
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL084976  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.

https://blogs.agu.org/thefield/2019/10/20/postcards-from-a-frozen-icebreaker-part-5/

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.

https://www.awi.de/en/science/geosciences/geophysics/methods-and-tools/ocean-bottom-seismometer.html
« Last Edit: October 24, 2019, 12:48:31 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #167 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
https://follow.mosaic-expedition.org/
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
« Last Edit: October 24, 2019, 01:55:04 PM by uniquorn »

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Re: MOSAiC news
« Reply #168 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.)
« Last Edit: October 24, 2019, 09:20:22 PM by A-Team »

gandul

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Re: MOSAiC news
« Reply #169 on: October 24, 2019, 06:00:21 PM »
Seems to be in a saddle point. displacement low, maximum shear deformation. That's not good
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Re: MOSAiC news
« Reply #170 on: October 24, 2019, 08:20:45 PM »
Quote
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.
« Last Edit: October 24, 2019, 08:31:48 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #171 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.

uniquorn

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Re: MOSAiC news
« Reply #172 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

Quote
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.

Quote
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
« Last Edit: October 25, 2019, 01:39:25 AM by uniquorn »

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Re: MOSAiC news
« Reply #173 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 month.day.year

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


https://www.cryosphereinnovation.com/data#Status-Filter
« Last Edit: October 25, 2019, 10:39:43 AM by A-Team »

A-Team

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Re: MOSAiC news
« Reply #174 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:

Quote
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]

https://physerver.hamilton.edu/Research/Brownian/Jigglyread.html  myths vs reality check
« Last Edit: October 25, 2019, 05:16:29 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #175 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.
« Last Edit: October 25, 2019, 04:59:56 PM by uniquorn »

Tor Bejnar

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Re: MOSAiC news
« Reply #176 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?   
Arctic ice is healthy for children and other living things.

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Re: MOSAiC news
« Reply #177 on: October 25, 2019, 06:26:44 PM »
Quote
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?

Quote
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 https://www.epochconverter.com/days/2019 . 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.

Quote
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.
« Last Edit: October 25, 2019, 06:48:33 PM by A-Team »

gerontocrat

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Re: MOSAiC news
« Reply #178 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.
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Re: MOSAiC news
« Reply #179 on: October 25, 2019, 10:33:15 PM »
Quote
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.
« Last Edit: October 25, 2019, 11:32:31 PM by A-Team »

uniquorn

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Re: MOSAiC news
« Reply #180 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 https://www.sailwx.info/shiptrack/shipdump.phtml?call=DBLK

JayW

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Re: MOSAiC news
« Reply #181 on: October 26, 2019, 06:26:41 PM »
"To defy the laws of tradition, is a crusade only of the brave" - Les Claypool

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Re: MOSAiC news
« Reply #182 on: October 26, 2019, 08:11:14 PM »
Holy moly that's amazing!  :o

Great find, Jay.
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Re: MOSAiC news
« Reply #183 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.
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uniquorn

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Re: MOSAiC news
« Reply #184 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.

A-Team

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Re: MOSAiC news
« Reply #185 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 https://scatterplot.online/ 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:
http://psc.apl.washington.edu/UpTempO/

Quote
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
https://www.frontiersin.org/articles/10.3389/fmars.2019.00429/full  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
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6308795/ free full
« Last Edit: October 27, 2019, 09:57:38 PM by A-Team »

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Re: MOSAiC news
« Reply #186 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)

https://doi.pangaea.de/10013/epic.65d66d94-ff77-461f-9119-3e8d4c2ae7f3

Quote
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. https://blogs.helmholtz.de/polarstern

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.
« Last Edit: October 27, 2019, 11:55:55 PM by A-Team »

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Re: MOSAiC news
« Reply #187 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
« Last Edit: October 28, 2019, 07:23:39 PM by uniquorn »

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Re: MOSAiC news
« Reply #188 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.

https://www.awi.de/fileadmin/user_upload/MET/PolarsternCoursePlot/psobsedat.html

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.
« Last Edit: October 29, 2019, 02:33:01 AM by A-Team »

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Re: MOSAiC news
« Reply #189 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 https://follow.mosaic-expedition.org

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.
« Last Edit: October 29, 2019, 04:53:04 PM by A-Team »

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Re: MOSAiC news
« Reply #190 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)
« Last Edit: October 29, 2019, 11:15:17 PM by uniquorn »

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Re: MOSAiC news
« Reply #191 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 seaice.de 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.

ftp://ftp.awi.de/sea_ice/product/cryosat2_smos/v202/nh/LATEST/ 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).


https://seaice.uni-bremen.de/data/smos_smap/png/north/2019/
https://seaice.uni-bremen.de/data/smos/png/20191030_hvnorth_rfi_l1c.png

Quote
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: ftp://ftp.awi.de/sea_ice/product/   Both SMOS data products underestimate the thickness on average by about 50-60%.
« Last Edit: October 31, 2019, 06:59:42 PM by A-Team »

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Re: MOSAiC news
« Reply #192 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.

Quote
SIMB3 Direct measurement of ice mass surface and bottom position change (mass balance)
https://www.cryosphereinnovation.com/simb3  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.
« Last Edit: November 01, 2019, 02:04:15 AM by A-Team »

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Re: MOSAiC news
« Reply #193 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?
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Re: MOSAiC news
« Reply #194 on: October 31, 2019, 10:49:07 PM »
A quick screengrab of the mass balance buoys at https://www.cryosphereinnovation.com/386840
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


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Re: MOSAiC news
« Reply #195 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 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.
day292-301


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Re: MOSAiC news
« Reply #196 on: November 01, 2019, 10:18:33 PM »
Quote
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:

https://manati.star.nesdis.noaa.gov/ascat_images/ice_image/msfa-NHe-a-2019304.sir.gif
https://manati.star.nesdis.noaa.gov/ascat_images/ascatB_ice_image/msfa-NHe-a-2019304.sir.gif
https://manati.star.nesdis.noaa.gov/ascat_images/ascatC_ice_image/msfa-NHe-a-2019304.sir.gif
https://www.epochconverter.com/days/2019 (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  12_2991_N_1.final.jpg
S1B_EW_GRDM_1SDH_20191030T 04:49  11_2203_N_1.final.jpg
S1B_EW_GRDM_1SDH_20191030T 06:27  16_846D_N_1.final.jpg

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.

Quote
Mapping pan-Arctic landfast sea ice stability using Sentinel-1 interferometry
DO Dammann et al
https://www.the-cryosphere.net/13/557/2019/ 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.
« Last Edit: November 01, 2019, 10:28:39 PM by A-Team »

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Re: MOSAiC news
« Reply #197 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.
« Last Edit: November 02, 2019, 06:43:18 PM by A-Team »

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Re: MOSAiC news
« Reply #198 on: November 03, 2019, 08:45:33 AM »
The World’s Largest Polar Expedition is Being Threatened by Thin Ice

Link >> https://www.thearcticinstitute.org/the-arctic-this-week-take-five-week-of-october-14-2019/?cn-reloaded=1
Refugees welcome

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Re: MOSAiC news
« Reply #199 on: November 03, 2019, 01:07:44 PM »