Here’s the latest graph of Arctic sea ice extent from JAXA/ViSHOP, with 2021 and 2015 highlighted:
Extent fell by over 100,000 square kilometres between February 16th and 17th! Can that steep fall continue, as it did for one more day in 2015?
Here too is Zack Labe’s 2021 overview of JAXA maximum extent over the previous couple of decades:
2015’s maximum was very early, on February 15th. Hence the current extremely tentative 2021 maximum is already both higher and later than that. The decadal average extent graphs show the date of the maximum getting later and later, and the 2010’s peaks in the middle of March.
It therefore seems likely that there is more freezing still to come this year. However lets take a look at the high resolution AMSR2 sea ice area graph for the Sea Of Okhotsk:
The recent fall in Arctic wide extent has evidently been driven by the recent rapid decline in this peripheral sea, where SMOS reveals more thin ice ripe for further melting:
In conclusion, the high res AMSR2 extent metric shows the tentative 2021 peak below that of 2015!
Following another 100k decline JAXA extent is still following the 2015 playbook remarkably closely:
Animation via NASA WorldView: https://go.nasa.gov/3axTEDu
P.S. See also:
but Boulder has a problem. The NSIDC’s information is stuck on February 19th:
The first conclusion to hastily jump to is that the venerable DMSP F17 satellite has finally failed, but according to Thomas Lavergne the problem is actually on the ground:
According to Thomas Lavergne the SSMIS data is flowing to OSI-SAF once again!
Hopefully the NSIDC’s Charctic graph will update later today. Meanwhile JAXA extent is flatlining:
The current JAXA maximum still stands at 13.98 million km² on February 16th. The NSIDC 5 day average maximum is currently at 14.54 million km² on February 15th.
JAXA extent is still decreasing slowly, and is now 3rd lowest for the date in their records. Here’s a comparison with previous years with comparatively low maxima:
Another leg down for JAXA extent, which is now second lowest for the date:
The NSIDC’s Charctic graph is updating again, and currently looks like this:
Meanwhile via Thomas Lavergne on Twitter here’s a CMEMS forecast for a sudden surge in extent to well above the current maximum for 2021:
The NSIDC extent metric seems to be suffering further problems today, but AMSR2 soldiers on:
The long awaited “rebound” in Arctic sea ice extent has begun before JAXA extent reached “lowest for the date (in the satellite record!)”. Hence for completeness I’ve added in the curve for 2006:
The “rebound” in JAXA extent continues apace, with a 100k gain yesterday:
The latest CMEMS forecast from Thomas Lavergne suggests this will continue for a few more days:
Following another 100k km² gain yesterday JAXA extent is racing back towards the year’s high:
However high resolution AMSR2 sea ice area has yet to follow suit. Data to February 27th:
In another intriguing development, a strong cyclone is heading into the Bering Sea. Here’s a picture of it taken by the Suomi NPP satellite:
and here is the resulting “surf” forecast for the Bering Sea at midnight tonight UTC:
I cannot help but wonder what effect a huge swell directed straight at the ice edge in the Bering Sea will have.
After yet another 100k km² gain JAXA extent has breached the 14 million level and reached a new maximum for the year:
The Bering Sea cyclone has been filling in today, but is now much closer to the ice edge:
The JAXA extent trend is still up, but the rate of increase has decreased today:
Here’s a glimpse of the state of the ice in the Bering Sea following the recent cyclone:
Meanwhile NSIDC extent is still not updating, and another cyclone is heading for the Bering Sea:
Here’s the latest CMEMS forecast from Thomas Lavergne, with the added bonus of the OSI_SAF extent graph:
JAXA extent is still increasing, and hence my graph is getting more crowded with earlier years:
However note that sea ice area is still well below the initial peak on February 15th:
The NSIDC’s Charctic extent graph has burst into life again, to reveal extent still rising:
High resolution AMSR2 Arctic sea ice area has also reached a new maximum for the year:
JAXA extent has finally recorded another down day:
The extremely tentative new JAXA maximum is 14.14 million km² on March 5th.
Yet another cyclone is spinning on the Pacific side of the Arctic, but this one is forecast to move over the central basin rather than just the periphery. Here’s the current Environment Canada synopsis at 12Z:
Plus the US Navy’s ice drift forecast for March 10th:
Another leg up for JAXA extent. Hence I’ve added 2007 to the list of years that 2021 extent is now greater than:
JAXA extent is still increasing:
and the most recent in the current sequence of Arctic cyclones appears to have bottomed out with a central MSLP of 960 hPa according to Environment Canada:
By way of comparison note that the “Great Arctic Cyclone” of August 2012 reached a minimum MSLP of 966 hPa.
The most obvious effect of the passage of the cyclone has been the opening up of this by now refrozen lead along the edge of the fast ice in the East Siberian Sea:
There are more Arctic cyclones on the way. Here is the ECMWF forecast for 0Z on Saturday, courtesy of TropicalTidbits:
There’s a 953 hPa MSLP cyclone over the Kara Sea, plus 970 hPa arriving in the Bering Sea. The isobars are also closely packed over the Fram Strait, so what with one thing and another it looks as though the 2021 maximum extent is still some way away.
JAXA extent is declining quickly once again:
The slightly less tentative maximum is now 14.24 million km² on March 10th.
The world’s assorted meteorological offices have different opinions on the minimum MSLP of the Kara Sea cyclone. GFS went for 950 hPa, but ECMWF settled for 952:
The next sub 970 hPa cyclone is currently forecast to enter the Central Arctic from the North Atlantic in a week or so. That’s still a long way off though, so we’ll take another look at that in a few days time.
JAXA extent is still declining, so the tentative maximum is looking more secure by the day. The NSIDC’s 5 day average is declining more slowly, but currently reveals a maximum of 14.75 million km² on March 12th:
The forecast cyclone on the Atlantic side of the Arctic changes from day to day and from model to model. However the ECMWF currently show it bottoming out at 959 hPa over the Barents Sea at 0Z on Sunday 21st:
Sunlight is now reaching 80N and beyond, so it is now possible for MODIS to see through the clouds and observe wind driven sea ice breaking up north of Svalbard:
NSIDC 5 day averaged extent has just posted a new maximum for the year. 14.767 million km² to be (overly?) precise:
JAXA, on the other hand, seems more than content to stick with the existing maximum:
All the extent metrics are now declining in unison, and the continual sequence of strong Arctic cyclones has paused for the moment. Barring unforeseen circumstances that leaves the 2021 Arctic sea ice maximum extent numbers as follows:
UH/Wipneus AMSR2 – 13.97 million square kilometres on March 11th
JAXA/ViSHOP AMSR2 – 14.24 million square kilometres on March 10th
NSIDC 5 day SSMIS – 14.77 million square kilometres on March 21st
NSIDC 1 day SSMIS – 14.87 million square kilometres on March 11th
OSI-SAF 1 day SSMIS – 14.99 million square kilometres on March 10th
The NSIDC have now issued a press release announcing the 2021 maximum extent:
Arctic sea ice has likely reached its maximum extent for the year, at 14.77 million square kilometers (5.70 million square miles) on March 21, 2021, according to scientists at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder. The 2021 maximum is tied with 2007 for seventh lowest in the 43-year satellite record.
Please note that the Arctic sea ice extent number is preliminary—continued winter conditions could still push the ice extent higher. NSIDC will issue a formal announcement at the beginning of April…
In addition NASA have produced a video to mark the event:
Watch this space, just in case!