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uniquorn

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Re: The caa-greenland mega crack
« Reply #150 on: August 16, 2020, 10:38:49 PM »
A brief peek through the clouds of the eddies north of Ellesmere Island.
That's a lot of eddies. The development awi amsr2 view, aug6-15

uniquorn

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Re: The caa-greenland mega crack
« Reply #151 on: August 24, 2020, 11:56:36 AM »
update using amsr2 awi(dev), jul17-23
cross posting worldview image, jul23, from the melting thread for reference. (light contrast enhancement)

uniquorn

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Re: The caa-greenland mega crack
« Reply #152 on: September 07, 2020, 01:16:58 AM »
shhh

bbr2315

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Re: The caa-greenland mega crack
« Reply #153 on: September 07, 2020, 03:41:16 AM »
The year the crack became.... a partially open sea?

uniquorn

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Re: The caa-greenland mega crack
« Reply #154 on: September 07, 2020, 01:36:08 PM »
amsr2-uhh, jul21-sep6

Freegrass

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Re: The caa-greenland mega crack
« Reply #155 on: September 07, 2020, 02:53:04 PM »
Look at the speed of that floe that flies from the most northern tip of Greenland towards the Fram. Is that the speed of the current? Or was that aided by wind?
When factual science is in conflict with our beliefs or traditions, we cuddle up in our own delusional fantasy where everything starts making sense again...

be cause

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Re: The caa-greenland mega crack
« Reply #156 on: September 07, 2020, 05:18:27 PM »
.. or was there a nuclear sub using it for cover ? :)
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 .. you gotta laugh .. :)

uniquorn

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Re: The caa-greenland mega crack
« Reply #157 on: September 07, 2020, 11:46:42 PM »
cyclone powered on sep2-4.  https://go.nasa.gov/3m2tht1 aug1-sep7

Glen Koehler

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Re: The caa-greenland mega crack
« Reply #158 on: September 08, 2020, 07:03:23 AM »
https://forum.arctic-sea-ice.net/index.php/topic,119.msg285372.html#msg285372
Monthly update from the Polar Science Center:
Quote
August 2020 Monthly Update
<snip>
 Ice thickness anomalies for August 2020 relative to 2011-2018 (Fig 6) continue the pattern that has emerged over the winter, spring and shows relatively thin ice along the Russian Coast and thicker than normal in the Eastern Beaufort and the along the Canadian Archipelago.
    How does PIOMAS see thicker than normal ice on the north coast of Ellesmere when the AMSR2 shows a lack of land fast ice at same location for August 2020?  One of them has to be wrong.

https://forum.arctic-sea-ice.net/index.php/topic,2839.msg285417.html#msg285417
amsr2-uhh, jul21-sep6
« Last Edit: September 08, 2020, 09:08:15 AM by Glen Koehler »

oren

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Re: The caa-greenland mega crack
« Reply #159 on: September 08, 2020, 08:56:03 AM »
PIOMAS suffers from low resolution and does not "see" the crack. I bet it is the one that is wrong.

interstitial

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Re: The caa-greenland mega crack
« Reply #160 on: September 09, 2020, 04:32:27 AM »
There at least 6 different amsr2 products. There may be more.

uniquorn

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Re: The caa-greenland mega crack
« Reply #161 on: September 09, 2020, 11:11:23 PM »
The caa-greenland mega fracture https://go.nasa.gov/2FoXSQY
« Last Edit: September 09, 2020, 11:51:49 PM by uniquorn »

uniquorn

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Re: The caa-greenland mega crack
« Reply #162 on: September 19, 2020, 11:19:53 PM »
as the sunlight fades, https://go.nasa.gov/2FKBrpB

uniquorn

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Re: The caa-greenland mega crack
« Reply #163 on: September 23, 2020, 11:11:46 AM »
amsr2-awi-v103, caa, sep4-22 (PM)
click for clarity and motion

uniquorn

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Re: The caa-greenland mega crack
« Reply #164 on: October 18, 2020, 12:35:06 AM »
CAA north coastal ice still restless. click for movement and full res.
https://go.nasa.gov/3lW02qZ

uniquorn

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Re: The caa-greenland mega crack
« Reply #165 on: October 23, 2020, 10:53:11 PM »
nth greenland oct16-23    https://go.nasa.gov/3jqDayn
Not that much open water, some of the darker coastal areas are fog over refreeze.

morganism

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Re: The caa-greenland mega crack
« Reply #166 on: October 23, 2020, 11:28:43 PM »
just put a note about this in the freezing thread, but it shows up well in the animation.

https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=3299.0;attach=289522;image

uniquorn

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Re: The caa-greenland mega crack
« Reply #167 on: November 07, 2020, 10:59:31 PM »
A small lift off north of Ellesmere. https://go.nasa.gov/2GH25jS

uniquorn

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Re: The caa-greenland mega crack
« Reply #168 on: November 18, 2020, 08:24:58 PM »
The restless sea. Similar view as above, https://go.nasa.gov/3kJcJEz nov5-18. There's a lot going on down there. click for movement
edit: better with clahe 1.7

added CS2SMOS merged thickness (note nov1-15)
found a better panoply map
« Last Edit: November 18, 2020, 09:32:58 PM by uniquorn »

uniquorn

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Re: The caa-greenland mega crack
« Reply #169 on: December 08, 2020, 10:53:03 AM »
The anticyclone having an effect. https://go.nasa.gov/3lWIquT dec4-7

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Re: The caa-greenland mega crack
« Reply #170 on: December 10, 2020, 07:58:11 PM »
Just wanted to add a link here to A-Team's remarkable video in the Mosaic thread.  Curiously, the crack seems to be positioned far from the coast, unless I'm just not seeing a smaller gap next to the coast?  Check out the last in the series here:

https://forum.arctic-sea-ice.net/index.php/topic,2906.msg295458.html#msg295458
"When the melt ponds drain apparent compaction goes up because the satellite sees ice, not water in ponds." - FOoW

uniquorn

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Re: The caa-greenland mega crack
« Reply #171 on: December 11, 2020, 02:55:39 PM »
Well spotted KenB, there are significant differences between CMEM'c neXtSIM model, https://tinyurl.com/y4aqh5dd and the satellite based viirs brightness temperature  https://go.nasa.gov/37WOhuX
Note also the large change in the model output between dec7 and dec8 though it appears to simulate the overall drift pattern pretty well.
Here is a very rough overlay for comparison dec6-10

uniquorn

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Re: The caa-greenland mega crack
« Reply #172 on: December 12, 2020, 11:26:28 PM »
Following up on the neXtSIM crack disappearance on Dec8 between 00h and 01h

Classification
Product ID   ARCTIC_ANALYSISFORECAST_PHY_ICE_002_011
Published   14 October 2016
Originating centre   NERSC (Norway)
Area   Arctic Ocean
Quote
The Arctic Sea Ice Analysis and Forecast system uses the neXtSIM stand-alone sea ice model running the Maxwell-Elasto-Brittle sea ice rheology on an adaptive triangular mesh of 10 km average cell length. The model domain covers the whole Arctic domain, excluding the Canadian Archipelago, the Baffin and Hudson Bays.

A couple of papers
https://escholarship.org/uc/item/214676bx
Sea ice diffusion in the Arctic ice pack: a comparison between observed buoy trajectories and the neXtSIM and TOPAZ-CICE sea ice models

“Generated using E.U. Copernicus Marine Service Information”
« Last Edit: December 14, 2020, 11:46:59 AM by uniquorn »

Glen Koehler

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Re: The caa-greenland mega crack
« Reply #173 on: December 14, 2020, 01:25:10 AM »
    Thanks to A-team and uniquorn for the heavy lifting on neXtSIM.

    The amount of change in just one hour in the two frames of the top image are hard to believe as being anything close to realistic.  The ice could not possibly have changed that much in one hour.  Are the date and time stamps correct?  Or does the methodology allow for large variation between images taken just one hour apart? 

    Not complaining, just trying to understand.  Even if neXtSIM images exaggerate variation, that is OK as long as the exaggeration is consistent and therefore can be accounted for in interpretation.   But if inconsistent, such as big differences in how the method distorts data for images just one hour apart, then interpretation becomes almost impossible because you won't know what degree of exaggeration to account for.  I'm rooting for neXtSIM as being a superbly informative monitoring tool if it comes with a stable frame of reference for how to interpret images.  Otherwise it would just be pictures that can mean different things at different days or hours, i.e. just images without much meaning.

uniquorn

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Re: The caa-greenland mega crack
« Reply #174 on: December 14, 2020, 01:34:22 AM »
https://marine.copernicus.eu/ have a chat help that responds quickly. They are closed at the moment. I keep forgetting to ask them about it.

uniquorn

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Re: The caa-greenland mega crack
« Reply #175 on: January 10, 2021, 04:44:09 PM »
Following up a bit late on the neXtSIM crack disappearance on Dec8 between 00h and 01h. Their response was quick.
The Dec8 problem appears to be resolved.
different palette, black near Lincoln Sea is allegedly over 4m by this model

uniquorn

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Re: The caa-greenland mega crack
« Reply #176 on: January 10, 2021, 04:49:14 PM »
Crack update. Small lift off from CAA coast, NE Ellesmere ice is holding on.

Niall Dollard

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Re: The caa-greenland mega crack
« Reply #177 on: January 11, 2021, 01:25:16 AM »
black near Lincoln Sea is allegedly over 4m by this model

Any idea where this black (4m) section in the Lincoln arrived from ? Did it migrate south from between Ellesmere and the Pole and has become trapped in the Lincoln ? By trapped I mean that with a clockwise rotation, the north of Ellesmere protrudes and hinders the clockwise movement over the top of Greenland.

I think if it is really a substantially thick piece of ice in the Lincoln, it probably played a significant role in the early arch formation in the Nares this season.   

uniquorn

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Re: The caa-greenland mega crack
« Reply #178 on: January 11, 2021, 06:48:59 PM »
Quote
Any idea where this black (4m) section in the Lincoln arrived from
neXtSIM models it as there all summer but I think regulars in the Nares thread would probably disagree, as does CS2SMOS, oct22-jan8 (click 5MB)
Quite a few large old MYI floes did enter the Nares though and there are still some in the Lincoln Sea.

oren

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Re: The caa-greenland mega crack
« Reply #179 on: January 12, 2021, 01:39:44 AM »
Quote
Any idea where this black (4m) section in the Lincoln arrived from
neXtSIM models it as there all summer but I think regulars in the Nares thread would probably disagree, as does CS2SMOS, oct22-jan8 (click 5MB)
Indeed, neXtSIM is simply wrong about the Lincoln Sea (as well as along the Ellesmere crack). Compare ice movements shown to what actually took place during the summer as can be seen in various Worldview animations posted on the melting season and other threads. It appears coastal modelling is far from perfect.

uniquorn

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Re: The caa-greenland mega crack
« Reply #180 on: January 25, 2021, 07:14:23 PM »
Mclure strait leads, jan25
Wider view including the Beaufort for reference, jan26    https://go.nasa.gov/3iNWeaU
unusual swaths on that image
« Last Edit: January 27, 2021, 12:35:08 AM by uniquorn »

Tor Bejnar

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Re: The caa-greenland mega crack
« Reply #181 on: January 27, 2021, 04:00:55 PM »
The more these cracks open during the cold winter months the more ice that is created. 

Very thin ice thickens much faster than thick ice under a given air temperature due to the insulating properties of ice (heat cannot escape as easily). Therefore, opening leads are ice factories.  I suspect a no-wind winter would be devastating to Arctic ice volume accumulation.
Arctic ice is healthy for children and other living things.

uniquorn

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Re: The caa-greenland mega crack
« Reply #182 on: January 27, 2021, 08:40:48 PM »
Agreed, the downside these days being that large multi year ice floes get broken up into smaller and smaller parts held together by weaker first year ice. suomi/npp brightness temperature goes back to sep2017, allowing us to compare 4 years on roughly this date, depending on clouds. Lift off of fast ice deep into the Mclure Strait is probably the least desirable part of the 2021 image.

https://go.nasa.gov/3t2uofW  2018-2021
« Last Edit: January 27, 2021, 09:40:41 PM by uniquorn »

uniquorn

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Re: The caa-greenland mega crack
« Reply #183 on: February 23, 2021, 10:55:32 PM »
A small lift off, not cutting so deep into the PGAS and Peary Channel. Brightness temperature showing the thinner ice from the Jan6 lift off. To the right, the Fram funnel wind shear line just visible by the cloud front on feb23



https://go.nasa.gov/3pNHOcS, feb20-23
« Last Edit: February 23, 2021, 11:08:39 PM by uniquorn »

uniquorn

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Re: The caa-greenland mega crack
« Reply #184 on: July 19, 2021, 08:32:19 PM »
blink and you miss it.
awi amsr2 v104, jul12-18

uniquorn

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Re: The caa-greenland mega crack
« Reply #185 on: August 12, 2021, 11:38:30 AM »
not much to crack
https://go.nasa.gov/3fUUfRY  high contrast to show floes.

gerontocrat

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Re: The caa-greenland mega crack
« Reply #186 on: August 12, 2021, 03:26:19 PM »
There seems to be something of a boundary between East (broken up ice) and West (fairly intact ice pack)

Image from North of Greenland attached as at pm on the 11th.

click image & then maximise
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Tor Bejnar

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Re: The caa-greenland mega crack
« Reply #187 on: August 12, 2021, 03:37:44 PM »
This post belongs here (but posted elsewhere because someone was suggesting it was a new feature).
The "megacrack" is not, actually, a new Arctic feature. 

Polynyas in the Canadian Arctic, "Occasional Paper Number  45 - Canadian Wildlife  Service" from 1981 - http://parkscanadahistory.com/wildlife/paper-45.pdf - discusses some of the history of open water in the Canadian Arctic, with maps from different events.
Quote
5.11. Arctic Ocean lead system

The Arctic Ocean is covered with pack ice which, under the forces of currents and winds, gradually moves in a clockwise direction. A zone of landfast ice forms along the outer Queen Elizabeth Islands, western Banks Island, and along the mainland coast (Fig. 12). Freeze-up along Banks Island can begin between the first of October (as in1978) and the first of November (as in 1977), or a week or two later along the mainland coast.

The boundary between the fast ice and the pack ice is commonly marked by a shore lead system which remains relatively constant from year to year, and corresponds to the continental shelf (Fig. 12). The lead system is often continuous from north of Ellef Ringnes Island south to Cape Bathurst on the mainland, and then west past Point Barrow. Alaska. InJanuary1975 it extended as far north as Robeson Channel, between Ellesmere Island and Greenland.

The lead opens and closes as the pack ice moves; thus it varies in width and continuity. It takes the form of some combination of leads, cracks, and patches of open water (Fig. 12) which in places may stretch up to tens of kilometres wide during winter. For short periods, open water may exist in the lead but, because of the rapid rate of ice formation in winter, there is usually a cover of new ice (Weeks 1978). As stated previously, it was not possible to differentiate new ice from open water on the NOAA imagery, so that all dark areas were mapped as open water. As the lead closes, the new ice is rafted or forced into pressure ridges which can be seen clearly even on NOAA images. From the daily coverage pro-vided by the NOAA imagery, it appears that the pack ice moves in and out quite frequently so that open water and/or new ice are persistent along this shore lead system.
One example from January 1979  (click to enlarge):
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uniquorn

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Re: The caa-greenland mega crack
« Reply #188 on: August 12, 2021, 03:54:18 PM »
Good background reading Tor, perhaps the thread could have a more appropriate title

@Gero - not sure where you are drawing your east/west line but I would put it along the Lomonosov ridge.
https://oden.geo.su.se/map/  providing a handy bathymetry overlay  at the moment
« Last Edit: August 12, 2021, 04:26:44 PM by uniquorn »

gerontocrat

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Re: The caa-greenland mega crack
« Reply #189 on: August 12, 2021, 04:38:02 PM »
@Gero - not sure where you are drawing your east/west line but I would put it along the Lomonosov ridge.
https://oden.geo.su.se/map/  providing a handy bathymetry overlay  at the moment
The map lets you switch off the ice to reveal the bathymetry beneath

Maybe the boundary sort of follows the dog leg from the ridge dead North of Greenland across to the Lomosov ridge?
Could this be a barrier to Atlantification heading West across the CAB between the Pole and Greenland / CAA?
Or just a coincidence from this year's somewhat odd melting season?
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uniquorn

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Re: The caa-greenland mega crack
« Reply #190 on: August 12, 2021, 04:42:40 PM »
<Or just a coincidence from this year's somewhat odd melting season?>

This year and last year

gerontocrat

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Re: The caa-greenland mega crack
« Reply #191 on: August 12, 2021, 06:57:05 PM »
<Or just a coincidence from this year's somewhat odd melting season?>

This year and last year
Archaeologists say 2 stones together are just 2 stones, 3 stones together make a wall.
If it happens again next year maybe the Lomosov ridge is a wall.
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uniquorn

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Re: The caa-greenland mega crack
« Reply #192 on: September 14, 2021, 12:25:36 AM »
awi amsr2 SIC v106, Lincoln/north Greenland, aug1-sep13.
Note the floe heading west in open water and the pulse at the entrance to the Nares.
« Last Edit: September 14, 2021, 12:32:13 AM by uniquorn »

A-Team

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Re: The caa-greenland mega crack
« Reply #193 on: September 14, 2021, 03:22:59 AM »
The large piece of landfast ice north of Morris Jesup fixed in Uniq's awi animation above is there regularly but does not persist every year. Although this is the site of the new northernmost bit of land in the Arctic, that gravel bar is closer in. The Oden found the bathymetry near by 500 m deeper than in Gebco charts.

This ice remnant really has to do with the highest latitude reached by the TransPolar Drift and its shear angle towards the Fram. It is revealed this year because of persistent southerly lift-off winds and melt which in turn enable east-west motion and eddies.

Because of high mobility and complete turnover of the ice in this region, it has nothing to do with the Last Ice which will extend from Ellesmere to Prince Patrick with a protected lee extension to the eastern Lincoln Sea. Neither the Wandel Sea nor Nares funnel areas have any prospects for persistence, contrary to these 2021 articles.

The Lincoln, which got studied a lot in decades past because of its proximity to Alert, was once thick and rigid but we have seen it completely broken up and exported numerous times in more recent years. It is currently in the process of turn-over.
« Last Edit: September 14, 2021, 02:10:42 PM by A-Team »

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Re: The caa-greenland mega crack
« Reply #194 on: September 14, 2021, 05:16:01 PM »
Quote
Who defined the so-called Last Ice Area and on what basis?
This term is being loosely used without citation in recent scientific articles. It appears to have been originated in 2013 by the Canadian chapter of the World Wildlife Federation.

The image below overlays that map onto the 13 Sep 2021 AWI map of sea ice concentration. The light blue shows Last Ice that is already open water 50 years ahead of the WWF wildlife-dependent ice protection goal.

The new protected area north of Ellesmere is called Tuvaijuittuq, an Inuit word for 'the place where the ice never melts'. They got that right.

The area north of Greenland is actually in bad shape already being low concentration sea ice in recent years, notably during the Mosaic polar expedition leg. As explained in the previous post, neither the Wandel nor Lincoln seas have any prospects of remaining stably ice covered.

Note the northern boundary on the map below has no predictive significance because it is simply the edge of the Canadian 'exclusive economic zone'.

The second map from Canadian oceans & fisheries is far more realistic. It does not include anything from Greenland and ends at Prince Patrick Island (which should extend further to the eastern tip of Banks Island and go farther north).

Since computer models out to 2050 are so flawed, it makes no sense to reference them. The final image shows the average open water in mid-September over the last ten years. The Last Ice Area can only be a subset of the white core ice area -- already the ice shelves, landfast ice along the CAA coast and peripheral seas can be ruled out as part of any ice refugium.

Technical note: Canada does not use polar stereographic projection in its maps and so re-projection onto polar satellite imagery cannot be not completely accurate.

https://wwf.ca/habitat/arctic/last-ice-area/

https://publications.gc.ca/collections/collection_2021/mpo-dfo/Fs97-6-3408-eng.pdf

S Pfirman 2009. The last Arctic sea ice refuge. Circle 4: pp. 6-8.
https://tinyurl.com/pk63vrcy

Identification of Ecologically and Biologically Significant Areas (EBSAs) in the Canadian Arctic. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2011/055
« Last Edit: September 14, 2021, 09:26:30 PM by A-Team »

gerontocrat

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Re: The caa-greenland mega crack
« Reply #195 on: September 14, 2021, 06:27:56 PM »
Going back to the here and now...

In recent days sea ice drift has been closing the crack, and even sending ice into the Greenland sea. (see attached image from http://ocean.dmi.dk/arctic/northeastwater.uk.php)

BUT, The attached sea ice drift map, even though it is for 3 days, shows that this has pretty much stopped.

The last 2 images suggest that sea ice drift will be reversed, opening the crack from NE Greenland perhaps as far as the Nares Strait entrance (if GFS has got it right about the persistence of this new weather pattern). Warmth is also involved.

An odd end to an odd melting season?
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kassy

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Re: The caa-greenland mega crack
« Reply #196 on: September 15, 2021, 04:42:39 PM »
This may not be the right place. 
Airbourne monitoring of sea ice north of Greenland have reported that this summer is the lowest sea ice thickness on record

https://www.meereisportal.de/en/archive/2021-kurzmeldungen-gesamttexte/icebird-summer-2021-first-results-of-sea-ice-thickness-measurements-taken-off-northeast-greenland/

The link also has this:
The (Wandel Sea) polynya in 2020 is described in detail in a paper by Schweiger et al., 2021, which analyses e.g. under which unique conditions the polynya formed last year, in a region normally considered to be part of the ‘Last Ice Area’ (i.e., the region in which the summer sea ice survives the longest). The combination of dynamic sea-ice movement away from the coast of Greenland over the spring and summer of 2020, and the increased absorption of solar energy in the now-open ocean, served to condition the Wandel Sea. Following several major storm events, in August 2020 the ice was pressed out of the Wandel Sea, while at the same time, the heat absorbed by the ocean in the spring and summer rose to the surface, which contributed to further ice melting and reduced ice thickness. In their paper, Schweiger et al. underscore that this development was generally promoted by the decline in multiyear ice, a product of climate change. As such, what set the year 2020 apart was the particularly pronounced atmospheric influence on the Wandel Sea in August 2020.

Accelerated sea ice loss in the Wandel Sea points to a change in the Arctic’s Last Ice Area
https://www.nature.com/articles/s43247-021-00197-5

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.