Author Topic: The caa-greenland mega crack (Read 43598 times)

uniquorn · « **Reply #150 on:** August 16, 2020, 10:38:49 PM »

Quote from: JayW on August 16, 2020, 07:41:41 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 · « **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 · « **Reply #152 on:** September 07, 2020, 01:16:58 AM »

bbr2315 · « **Reply #153 on:** September 07, 2020, 03:41:16 AM »

The year the crack became.... a partially open sea?

uniquorn · « **Reply #154 on:** September 07, 2020, 01:36:08 PM »

amsr2-uhh, jul21-sep6

Freegrass · « **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?

be cause · « **Reply #156 on:** September 07, 2020, 05:18:27 PM »

.. or was there a nuclear sub using it for cover ?

uniquorn · « **Reply #157 on:** September 07, 2020, 11:46:42 PM »

cyclone powered on sep2-4. https://go.nasa.gov/3m2tht1 aug1-sep7

Glen Koehler · « **Reply #158 on:** September 08, 2020, 07:03:23 AM »

https://forum.arctic-sea-ice.net/index.php/topic,119.msg285372.html#msg285372

Quote from: oren on September 07, 2020, 02:40:53 AM

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

Quote from: uniquorn on September 07, 2020, 01:36:08 PM

amsr2-uhh, jul21-sep6

oren · « **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 · « **Reply #160 on:** September 09, 2020, 04:32:27 AM »

There at least 6 different amsr2 products. There may be more.

uniquorn · « **Reply #161 on:** September 09, 2020, 11:11:23 PM »

The caa-greenland mega fracture https://go.nasa.gov/2FoXSQY

uniquorn · « **Reply #162 on:** September 19, 2020, 11:19:53 PM »

as the sunlight fades, https://go.nasa.gov/2FKBrpB

uniquorn · « **Reply #163 on:** September 23, 2020, 11:11:46 AM »

amsr2-awi-v103, caa, sep4-22 (PM)
click for clarity and motion

uniquorn · « **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 · « **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 · « **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 · « **Reply #167 on:** November 07, 2020, 10:59:31 PM »

A small lift off north of Ellesmere. https://go.nasa.gov/2GH25jS

uniquorn · « **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

uniquorn · « **Reply #169 on:** December 08, 2020, 10:53:03 AM »

The anticyclone having an effect. https://go.nasa.gov/3lWIquT dec4-7

KenB · « **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

uniquorn · « **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 · « **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”

Glen Koehler · « **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 · « **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 · « **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 · « **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 · « **Reply #177 on:** January 11, 2021, 01:25:16 AM »

Quote from: uniquorn on January 10, 2021, 04:44:09 PM

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 · « **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 · « **Reply #179 on:** January 12, 2021, 01:39:44 AM »

Quote from: uniquorn 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)

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 · « **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

Tor Bejnar · « **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.

uniquorn · « **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

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Author Topic: The caa-greenland mega crack (Read 43598 times)