If the 2021 maximum Arctic sea ice extent is more your thing then please see the previous article:
“The 2021 Maximum Arctic Sea Ice Extent“
Maximum volume is still several weeks away, but let’s first of all take a look at the PIOMAS modelled volume numbers for February. They are not yet available via the University of Washington’s Polar Science Center web site, but Wipneus has once again crunched the gridded thickness numbers which are already available. Here is what they reveal:
As you can see, it will be a big surprise if the 2021 volume maximum occurs in March rather than April, and 2021 is currently 3rd lowest for the date, behind 2017 and 2018. For completeness here too is the PIOMAS thickness map for the end of February:
This does contain some surprises, such as an area of thick ice along the shore of the East Siberian Sea, but no such thing along the north coast of Greenland, the traditional bastion of “the thickest ice in the Arctic Ocean”.
The “measured” Arctic sea ice volume calculated from CryoSat-2 and SMOS thickness data has also updated to February 28th:
Note that the “near real time” figures graphed in blue will almost certainly be revised upwards when the “reanalysed” data is released in a couple of weeks. Equally certainly they will be “lowest for the date” in the 11 year record.
Here also is the CS2/SMOS thickness map for February 28th for comparison purposes:
There has recently been some debate on the Arctic Sea Ice Forum about where the thickest ice in the Arctic is currently located. If you watch this ASCAT animation of the 2020/21 freezing season thus far carefully you can see there is still a large area of multi-year ice around the North Pole, in particular reaching towards Svalbard:
An equivalent area of thicker ice in that area seems to be strangely lacking in this GOFS thickness map:
By way of comparison, here’s ASCAT’s view of the 2019/20 freezing season:
For some further historical context and another ASCAT animation see also:
“Where’s the Thickest Arctic Sea Ice Gone?“
The February 2021 update is now available on the Polar Science Center web site. As well as the latest updates on Arctic sea ice volume it also includes these thickness anomaly maps for both PIOMAS and CS2/SMOS. Note that since CryoSat-2 didn’t launch until 2010 the anomaly baseline in both cases is 2011-2020:
The ice thickness anomaly map for February 2021 relative to 2011-2020 shows a mixture of positive and normal anomalies across the Arctic with strong negative anomalies stretching from North of Greenland into the Eastern Beaufort. Strong positive anomalies exists near the East Siberian Sea, along the Siberian Coast of the Chukchi. Thicker than normal (2011-2020) ice is also present in the Beaufort. A strong positive anomaly is notable in the Laptev Sea. CS2/SMOS satellite data show a broadly similar anomaly pattern but the positive anomalies in the East Siberian and Chukchi Seas are much weaker.
The mid month PIOMAS gridded thickness numbers have been released. Here’s the map for mid March:
plus the calculated volume and anomaly thereof:
The PIOMAS model currently places 2021 at 5th lowest for the date, with thick ice still building on the shores of the East Siberian Sea. The CS2/SMOS thickness map is still showing significantly thinner ice in the same area:
The end of March PIOMAS gridded thickness numbers have been mapped by Wipneus:
They show the fast ice on the shores of the East Siberian Sea getting ever thicker, but once again C2S/SMOS begs to differ on the current thickness in that vicinity:
Maximum volume is still some weeks away, but according to the available CS2/SMOS data Arctic sea ice volume is currently lowest for the date. As suggested by the discontinuity in the graph, it seems prudent to take the “near real time” values with a large pinch of salt until the reanalysed data is published, since it looks as though there is still an issue with NRT data on the Russian side of the Arctic:
By way of a contrast, 2021 is currently 6th lowest for the date in the PIOMAS data:
Perhaps maximum volume anomaly has been reached for this winter though?
The March 2021 monthly update is now available on the Polar Science Center web site:
Average Arctic sea ice volume in March 2021 was 21,700 km³. This value is the fifth lowest on record for March about 2,000 km³ above the record set in 2017. Monthly ice volume was 38% below the maximum in 1979 and 25% below the mean value for 1979-2020.
The ice thickness anomaly map for March 2021 relative to 2011-2020 shows a mixture of positive and normal anomalies across the Arctic with strong negative anomalies stretching from North of Greenland into the Eastern Beaufort. Strong positive anomalies exists along the Siberian Coast. Thicker than normal (2011-2020) ice is also present in the Beaufort.
The update also includes this comparison with CryoSat-2/SMOS volume, which highlights the current divergence between the two metrics:
Whilst we eagerly await the mid month PIOMAS update, and having recently validated the Great White Con homebrew volume processing with the professionals, it is not beyond the bounds of possibility that the maximum CryoSat-2/SMOS volume for 2021 will ultimately prove to have occurred on March 22nd or thereabouts:
Here too is the latest AWI “near real time” thickness map:
The mid month PIOMAS gridded thickness data has arrived, and also reveals an early initial peak in Arctic sea ice volume this year, and hence an increasingly negative anomaly:
Here too is the modelled thickness map
and Fram Strait export graph:
Speaking of Fram Strait export, here’s an informative animation:
The final reprocessed CryoSat-2/SMOS Arctic sea ice thickness data of the 2020/21 season has just been published by AWI. Here is the resulting volume graph:
The official PIOMAS numbers for April haven’t been published yet, but Wipneus’s calculation based on the gridded thickness data is remarkably accurate. Subject to a last minute correction the maximum Arctic sea ice volume metrics for 2021 read as follows:
PIOMAS – 22550.0 km³ on April 3rd
CS2/SMOS – 18060.5 km³ on April 7th
Watch this space!