The 2021 Maximum Arctic Sea Ice Extent

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!

[Edit – February 19th]

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:

[Edit – February 22nd]

Now seems like a good time to compare JAXA AMSR2 extent with the NSIDC flavour of an Arctic sea ice extent metric, based on SSMIS data. JAXA still hasn’t rebounded significantly:

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:

[Edit – February 23rd]

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.

P.S. It’s nearly midnight UTC, and while Charctic is still stuck on February 19th this graph is now visible on the NSIDC “Arctic Sea Ice News & Analysis” page:

[Edit – February 24th]

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:

[Edit – February 25th]

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:

Watch this space!

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