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Messages - uniquorn

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1
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 18, 2019, 10:57:00 PM »
whoi-itp103 unsure where to go again at the mouth of the amundsen gulf. Another temperature spike at 6 and 7m, salinity also higher this time with less melt above.
https://www.whoi.edu/page.do?pid=163356

2
Arctic sea ice / Re: MOSAiC news
« 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.

3
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: October 18, 2019, 01:01:03 AM »
mercator 0m salinity overlaid with uni-hamburg amsr2-uhh concentration at 60% transparent. 0% concentration, normally dark blue, has been set to fully transparent. sep17-oct16. click to run.

4
Arctic sea ice / Re: MOSAiC news
« 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.

5
Arctic sea ice / Re: MOSAiC news
« on: October 17, 2019, 04:50:58 PM »
A quick overview of mosaic Pbuoy drift before moving on to others.

6
Developers Corner / Re: Test space
« on: October 11, 2019, 07:18:53 PM »
:) fix is good

7
Arctic sea ice / Re: The 2019/2020 freezing season
« on: October 10, 2019, 11:42:50 AM »
Could be that Lorenzo's waves took a toll on the Atlantic Ocean side, especially around Svalbard?
Strange to see such a drop on October.
I think the continual export into FJL and Svalbard area over the summer was more unusual. Ice along the atlantic edge has been weakened or melted by sitting over a warm current all that time. Now the drift has temporarily? changed direction it offers little resistance. Yes, it's strange that this has come so late.
unihamburg amsr2-uhh, atlantic side, oct3-9
edit: looking at the forecast, export should resume shortly.

8
Developers Corner / Re: Test space
« on: October 09, 2019, 06:03:08 PM »
Quote
I made the bathy work on ITP 116
Tried this in ms edge which seems fastest to load. It works well, though the movement jerks a bit. Similar performance with chrome.

Thanks for the tip on salinity. There were quite a few more references to tempC but easy to find once I got the idea. Names instead of numbers...novel ;)

Why not tempC>2?

9
Developers Corner / Re: Test space
« on: October 09, 2019, 01:21:20 PM »
Good progress. I got stuck attempting to change the temperature bar to salinity but my R plotly knowledge is zero. I couldn't see how to change the variable. :( Is it possible to show temp and salinity on the same scene?
I'm also wondering about using your 2d version for the mosaic iatb buoys http://iabp.apl.washington.edu/maps_daily_table.html though manual download is a bit laborious.

10
Arctic sea ice / Re: The caa-greenland mega crack
« on: October 09, 2019, 01:06:57 PM »
Today's worldview viirs brightness temperature, band15, night with yesterday's amsr2-uhh inset.
https://go.nasa.gov/2MvVvvg
click for full resolution

11
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: October 08, 2019, 05:32:19 PM »
Clear enough weather over lincoln sea and part of ellesmere to take a look on worldview, viirsbt15n, sep oct6-8  https://go.nasa.gov/2odfrv3

12
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: October 08, 2019, 12:02:11 AM »
Thanks for the 'on the ground' image GAWLab. amsr2-uhh doesn't look quite the same :)
edit: added today's image (for yesterday) to the animation with the open water showing very clearly. Thanks for the 'heads up'.
oct1-7.

13
Developers Corner / Re: Test space
« on: October 07, 2019, 08:43:43 PM »
itp116 10-50m. Code works in Rstudio out of the box (after installing plotly properly)

14
Arctic sea ice / Re: Latest PIOMAS update (October 2019)
« on: October 06, 2019, 04:09:17 PM »
Thanks Wipneus. Here's an animation of the piomas thickness difference collage, feb-sep, for 2019

15
Arctic sea ice / Re: MOSAiC news
« 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 https://www.nhc.noaa.gov/gccalc.shtml, maybe helicopter.

16
Arctic sea ice / Re: MOSAiC news
« 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.
https://go.nasa.gov/35cKcRd
buoy type is SVP=surface velocity profiler http://iabp.apl.washington.edu/Acronyms.html

17
Arctic sea ice / Re: MOSAiC news
« on: October 04, 2019, 11:12:17 PM »
Polarview this morning

18
Arctic sea ice / Re: The 2019/2020 freezing season
« on: October 04, 2019, 02:25:39 PM »
Mercator (model) SST with unihamburg amsr2-uhh overlay at 60% transparent (0% concentration set to fully transparent) sep24-oct3. click to run
Warm pacific water still entering the chukchi from the pacific. Atlantic 'battle of the bulge' continues. Refreeze apparently making headway in the Laptev

19
Arctic sea ice / Re: The 2019/2020 freezing season
« on: October 01, 2019, 01:02:51 PM »
There's a lot going on above the pea green soup of the Laptev, but I'm not sure it's refreeze yet.
https://go.nasa.gov/2npk5FM

20
Arctic sea ice / Re: MOSAiC news
« on: October 01, 2019, 12:16:49 PM »
Polarview 16bit jp2 of yesterday's red triangle area with heavy contrast (saved as jpeg)

21
Arctic sea ice / Re: MOSAiC news
« 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.
https://www.polarview.aq/arctic

22
Arctic sea ice / Re: MOSAiC news
« on: September 30, 2019, 10:22:23 AM »
https://twitter.com/MOSAiCArctic/status/1178323545920696320

Quote
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 https://www.meereisportal.de

Meerisportal links to http://iabp.apl.washington.edu/maps_daily_table.html where there are 2 new buoys reporting from day 272 with rather conflicting data (Ts=surface temperature, Ta=atmospheric temperature)
Quote
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)

23
Arctic sea ice / Re: MOSAiC news
« 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.

24
Arctic sea ice / Re: The 2019/2020 freezing season
« on: September 29, 2019, 11:05:10 AM »
Mercator sea temperature 0m overlaid with unihamburg amsr2-uhh at 50pc transparent. amsr2 0% ice (open water, normally dark blue) has been set to fully transparent. sep1-28.

The CAB pushing into the Beaufort meeting resistance with warm water from amundsen gulf  and eastern chukchi. The warm current from east spitzbergen finally making headway against the ice export towards the fram strait. Similarly with the warm current from the Kara sea. Laptev also warm.
Warm winds forecast across chukchi over the next few days.
Hurricane Lorenzo forecast to move north at speed.
click to run

25
Arctic sea ice / Re: MOSAiC news
« on: September 28, 2019, 01:25:49 PM »
gmrt bathymetry with rough sailwx PS location overlay
https://www.gmrt.org/GMRTMapTool/np/
https://www.sailwx.info/shiptrack/shipposition.phtml?call=DBLK

edit: better overlay

26
Arctic sea ice / Re: The 2019/2020 freezing season
« on: September 28, 2019, 12:19:34 AM »
The CAB launching itself into the Beaufort.
Worldview, aqua modis, sep21-27  click to run

27
Arctic sea ice / Re: MOSAiC news
« 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

28
Arctic sea ice / Re: MOSAiC news
« 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.

29
Arctic sea ice / Re: MOSAiC news
« 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

30
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 23, 2019, 01:16:22 PM »
Does R do anything 3D? Playing around with imageJ gave me this so far...
going to dev thread

31
Arctic sea ice / Re: MOSAiC news
« 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
https://www.sciencemag.org/news/2014/09/alone-arctic-ice-floe-hovercraft

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:  <https://vimeo.com/174631373>  (remove chevrons)

32
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 22, 2019, 10:34:03 PM »
If the model is correct there is also a more clearly defined atlantic finger reaching into the Beaufort from the CAA. See https://forum.arctic-sea-ice.net/index.php/topic,2417.msg188825.html#msg188825 for animation going back to 2017.

This is interesting from the mosaic expedition:
 https://epic.awi.de/id/eprint/50082/1/Expeditionsprogramm_PS122.pdf   page 55
Quote
Outline The sea ice in the Arctic Ocean is changing under global warming, and there is evidence that the inflow of Atlantic water (AW) has reduced the upper ocean stratification enough, such that convective wintertime deepening of the mixed layer may have caused a sizable upward heat flux in parts of the Eurasian Basin. In the more permanently ice-covered central regions of the Arctic Ocean, it is thought that the halocline still prevents vertical mixing and thus, strong upward heat fluxes year-round. However, wintertime measurements hardly exist. Near-surface trapping of heat during the late summer has been of growing importance as the influence of solar radiation entering the ocean increases with snow melt, melt-pond formation and increasing open water fraction of the ice-pack. Observing a full seasonal cycle as well as studying the ice-ocean-atmosphere system in the Arctic at shorter timescales using an extended set of parameters will be extended in an unprecedented manner by MOSAiC. The specific focus of the OCEAN team is here on the physical parameters of the upper ocean, bounding on the sea-ice and the atmosphere, and the interaction with the lower parts of the water column. This will not only improve our understanding of the physics of the upper ocean at times where no or few measurements exist and throughout a full seasonal cycle but also improve our understanding of feedbacks with the sea-ice/snow, the lower atmosphere, biogeochemical processes and the ecosystem. The overall aim of our work is to understand, throughout all seasons, the dynamics in the upper Arctic ocean mixed-layer and the halocline on the scale of turbulent vertical mixing to the (sub)mesoscale, embedded in the Arctic system of large-scale advective pathways of different water masses.

33
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 20, 2019, 11:55:48 PM »
Great news :)
Reposting  whoi itp110 7m-50m from 2018, day264 to 2019, day120 (at location -134.8350  73.6623N) with location insert.

edit: corrected label and added part2
whoi itp110 7m-80m from 2019, day123-218
density green, temperature purple, salinity red
temp    -1.8 to 0.6C
salinity  27.5 to 31.2
density 1021.5 to 1025kg/m^3

34
Arctic sea ice / Re: "Stupid" Questions :o
« on: September 19, 2019, 10:27:19 PM »
It may be a good idea to look at temperature and salinity data from buoys. Pacific and Atlantic sides have quite different profiles but the idea is the same. Water density follows salinity much more closely than temperature (at arctic ocean temps).
Ocean depth makes a difference, notably on the atlantic side, maybe due to the higher latitude and drift. Beaufort/CAB is deep, but often melts, perhaps due to shallow, low salinity warming. ESS is shallow but melts late, perhaps due to near surface permafrost.

itp110, beaufort, a while ago ...click to run
itp116, nth of greenland, more recently.

I ran a lot density gifs but they are quite similar to salinity
https://forum.arctic-sea-ice.net/index.php/topic,2417.msg212911.html#msg212911

35
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 17, 2019, 12:38:43 PM »
Following up on the 2 buoys above, here is amsr2-uhh overlaid onto mercator 0m temperature at 60% transparency, amundsen gulf and mclure strait, jul1-sep15. amsr2-uhh 0% concentration, normally dark blue, has been set to fully transparent.

36
Arctic sea ice / Re: The 2019 melting season
« on: September 16, 2019, 11:07:09 PM »
amsr2-uhh overlaid onto mercator 0m temperature at 60% transparency, sep15. amsr2 0% concentration, normally dark blue, has been set to fully transparent.

37
Arctic sea ice / Re: The 2019 melting season
« on: September 16, 2019, 10:05:24 AM »
Wipneus regional extent updated today.  https://sites.google.com/site/arcticseaicegraphs/regional
2019 CAB extent looking likely to join 2018 (brown) in a later refreeze. Not a trend yet but perhaps 2012 (yellow) was an indication of the shape of things to come.

edit: osisaf ice drift, sep8-15. Compaction in many areas, especially on the atlantic side west of FJL.

38
Arctic sea ice / Re: MOSAiC news
« 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).

39
Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 10:07:13 PM »
The latest NSIDC "quick look" sea ice age map:
Thanks Jim. Animation for (most of) this melting season from week ending mar25-sep2
edit: ani removed as it is reposted downthread

40
Developers Corner / Dev library
« on: September 12, 2019, 11:48:41 AM »
Resizing table for overlays:
satellite           pxl       %      ~km/pxl    ~km^2/pxl
SMOS              397.5    75.815   11.92      5.06
Ascat              524.3   100.000    9.04      6.67
OsiSaf            1075.5   204.711    4.41     13.66
SMOS-SMAP   1146.0   218.577    4.13     14.59
AMSR2           1197.6   228.419    3.96     15.24



41
Arctic sea ice / Re: MOSAiC news
« 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
Quote
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.
https://en.wikipedia.org/wiki/CTD_(instrument)

42
Arctic sea ice / MOSAiC news
« on: September 11, 2019, 11:43:21 AM »
The MOSAiC expedition begins on the Sep20.

Quote
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:  https://www.meereisportal.de/en/mosaic/

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
 

43
Arctic sea ice / Re: The 2019 melting season
« on: September 10, 2019, 08:25:46 PM »
This sentinel image in the pack north of Svalbard shows some freezing between the floes.
I suspect if i am up against 3 veterans then the chances are that its clouds  :'(
Thanks both for taking the time to search for early signs of refreeze :)

update on whoi itp103, a buoy currently at the entrance to amundsen gulf. Both microcats, mounted at 5m and 6m depth reporting a significant temperature increase with a smaller salinity increase today. My first thought was that the floe it may still be tethered to had melted out, but as the increase is larger at 6m perhaps it is a warm current. edit: or mixing due to eddies (suggested by sailor on the other thread)
https://www.whoi.edu/page.do?pid=163356

More details from yesterday here https://forum.arctic-sea-ice.net/index.php/topic,2417.msg227639.html#msg227639

44
Arctic sea ice / Re: The 2019 melting season
« on: September 10, 2019, 12:20:29 PM »
Polarview sentinel1, western cab, sep9   https://www.polarview.aq/arctic

45
Arctic sea ice / Re: The 2019 melting season
« on: September 08, 2019, 03:00:03 PM »

46
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 07, 2019, 10:14:21 PM »
amsr2-uhh overlaid at 60% transparency onto mercator SST, mar21-sep6
removed

47
Arctic sea ice / Re: The 2019 melting season
« on: September 07, 2019, 10:08:27 PM »
the slush that counts for extent these days
If the mercator model is correct slush dispersion doesn't significantly affect SST yet. Depending on the weather, extent may follow 2018's slush path (brown) to meet 2012 (yellow).
amsr2-uhh overlaid at 60% transparency onto mercator SST, aug1-sep6
wipneus regional extent, CAB, sep6
piomas percentage of maximum by year, CAB, 2011-2019
edit:forgot scale

48
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 07, 2019, 01:01:06 PM »
A very different profile for whoi itp116 on the atlantic side, day234-250(sep7)
https://www.whoi.edu/page.do?pid=164836
The salinity scale is the same as upthread for comparison. Temperature had to be increased to 1.5C

49
Arctic sea ice / Re: The 2019 melting season
« on: September 05, 2019, 09:16:47 PM »
August Area, Extent & Volume losses may have been low, but SST anomalies continued to climb and expand.
I wish I had saved the images from the beginning of the melting season. But I did not. mea culpa.

A quick search didn't reveal DMI's SST file locations. NOAA's SST products going back to 2015 can be found here https://polar.ncep.noaa.gov/sst/ophi/ with a link to the archives.

Quote
A daily, high-resolution, real-time, global, sea surface temperature (RTG_SST) analysis has been developed at the National Centers for Environmental Prediction/Marine Modeling and Analysis Branch (NCEP / MMAB). The analysis was implemented in the NCEP parallel production suite 16 August 2005. It became fully operational on September 27, 2005.
The daily sea surface temperature product is produced on a twelfth-degree (latitude, longitude) grid, with a two-dimensional variational interpolation analysis of the most recent 24-hours buoy and ship data, satellite-retrieved SST data, and SST's derived from satellite-observed sea-ice coverage. The algorithm employs the following data-handling and analysis techniques:
    Satellite retrieved SST values are averaged within 1/12 o grid boxes with day and night 'superobs' created separately for each satellite;
    Bias calculation and removal, for satellite retrieved SST, is the technique employed in the 7-day Reynolds-Smith climatological analysis;
    Currently, the satellite SST retrievals are generated by a physically-based algorithm from the Joint Center for Satellite Data Assimilation. Retrievals are from NOAA-19 and METOP-A AVHRR data;
    SST reports from individual ships and buoys are separately averaged within grid boxes;
    The first-guess is the prior (un-smoothed) analysis with one-day's climate adjustment added;
    Late-arriving data which did not make it into the previous SST analysis are accepted if they are less than 36 hours old;
    Surface temperature is calculated for water where the ice cover exceeds 50%, using salinity climatology in Millero's formula for the freezing point of salt water:
        t(S) = -0.0575 S + 0.0017 S3/2 - 0.0002 S2,
    with S in psu.
    An inhomogeneous correlation-scale-parameter l, for the correlation function: exp(-d2/l2) , is calculated from a climatological temperature gradient, as
        l = min ( 450 , max( 2.25 / |grad T| , 100 )),
    with d and l in kilometers. "grad T" is in oC / km
Evaluations of the analysis products have shown it to produce realistically tight gradients in the Gulf Stream regions of the Atlantic and the Kuroshio region of the Pacific, and to be in close agreement with SST reports from moored buoys in both oceans. Also, it has been shown to properly depict the wintertime colder shelf water -- a feature critical in getting an accurate model prediction for coastal winter storms.

     Description of changes effective November 1, 2016
        The analysis now uses satellite SST retrieval data from the GOES satellites. In addition, the values of "SST" over land areas are now generated by an SOR Laplacian solver, which replaces the legacy "weaver" code.
    Description of changes effective August 26, 2016
        Handling of satellite SST retrieval data in the analysis was modified so the analysis will proceed in the absence of satellite data.

    Description of changes effective July 15, 2015
        Hot spots in the Sea of Azov and Caspian Sea were replaced by more temperate values of SST. Cool Congolese waters were replaced using a climatology from Robert Grumbine.
Here showing sep4, 2015-2019 for comparison.
edit: dates were in the wrong order, forgot scale
@bbr - hudson bay quite cool the last 2 years

50
Here looking at interferometry on worldview to highlight stationary ice against movement. This example shows the ESS east of NSI, jun20-28 with 2day time lag
More on interferometry here: https://forum.arctic-sea-ice.net/index.php/topic,1259.msg143664.html#msg143664
makes a change from white

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