As in previous years there is already a thread devoted to this year’s minimum extent. By way of a summary here are the end of August numbers for our favourite “high resolution” AMSR2 area and extent metrics:
Extent is currently near the top of the range of the last 10 years.
We have now reached the stage of the “melting season” when “refreezing” has started in the Central Arctic but melting at the periphery is outpacing it. However the Canadian Ice Service stage of development charts now show the arrival of new ice in the high latitudes of the Canadian Arctic Archipelago:
Note the areas coloured pink and labelled G and I. It also seems likely that the large areas of open water near the North Pole will start refreezing soon, if they have not already done so:
Further south in the CAA the deep water route through the Northwest Passage via the Parry Channel looks as though it is now wide open, on the AMSR2 concentration map at least! The CIS have yet to produce daily ice charts of McClure Strait, so we await the next weekly charts with great interest.[Edit – September 5th]
The August PIOMAS gridded thickness data has been released so here is the “unofficial” Arctic sea ice thickness map for August 31st:
Here too is the daily volume graph:
On August 31st volume was 5.367 km3, now 10th lowest in the satellite era.[Edit – September 14th]
The remains of Typhoon Merbok is forecast to bring some late melting season excitement to the Chukchi Sea by the weekend:
In other news a most interesting new paper has just been published:
“A year-round satellite sea-ice thickness record from CryoSat-2“
The paper is paywalled, but an online version can be viewed here:
Satellite observations of sea-ice thickness are currently unavailable during the crucial melt period from May to September, when they would be most valuable for applications such as seasonal forecasting6, owing to major challenges in the processing of altimetry data7. Here we use deep learning and numerical simulations of the CryoSat-2 radar altimeter response to overcome these challenges and generate a pan-Arctic sea-ice thickness dataset for the Arctic melt period.
Year-round Arctic sea ice thickness data from CryoSat-2 is now available for 2010-2020 via the British Antarctic Survey web site.
Now I cannot help but wonder when the summer 2022 Cryosat-2 Arctic sea ice thickness data will be released![Edit – September 16th]
Merbok is undoubtedly going to give the Bering Sea coast of Alaska a hammering:
Here’s the current NWS flood warning for Nome:
* WHAT...Significant coastal flooding expected. * WHERE...Southern Seward Peninsula Coast. * WHEN...From 6 PM Friday to 10 AM AKDT Sunday. * IMPACTS...Numerous roads may be closed. Low lying property including homes, businesses, the airport, and other critical infrastructure will be inundated. Some shoreline erosion will occur. * ADDITIONAL DETAILS...In Nome water levels will be 8 to 11 feet above the normal high tide line. Areas near the mouth of the Snake river, and upstream, will also be inundated as water backs up in the river due to the storm surge. The Belmont Subdivision will be significantly impacted by flooding, as will the Airport Terminal, and some areas of the runway may be flooded. Streets on the west side of town may also be flooded.
But what of further north in the Chukchi Sea? The GFS Wave forecast currently suggests a 10 second, 3 meter plus swell heading for the ice edge on Sunday:
Here’s the current NWS map of sea ice concentration in the Chukchi Sea and thereabouts:
It will be interesting to see how it looks in a few days time.[Edit – September 18th]
The centre of ex Typhoon Merbok is now north of the Arctic Circle, having passed over the Bering Strait last night UTC:
The Earth’s climate is currently in the midst of a “triple dip” La Niña, but the sea surface temperature anomaly map shows that the North Pacific is currently anomalously warm, which perhaps explains how a typhoon can find enough fuel to reach the Arctic:
Sea temperatures in the Chukchi Sea are also anomalously warm at the moment, and now look set to stay that way for some time. Here’s the GFS forecast Arctic minimum air temperature map for the next 5 days:
Here’s an animation of the last few days sea ice concentration on the Pacific side of the Central Arctic:
[Click to animate. Updated to September 20th]
There is enough open water in the Chukchi and East Siberian Seas to allow a significant ocean swell to develop. JAXA Arctic sea extent showed an extremely modest uptick yesterday, but will that trend continue?[Edit – September 19th]
What remains of Typhoon Merbok is still spinning strongly over the Chukchi Sea:
The storm has generated plenty of wind waves:
There is also enough open water on the Pacific side of the Arctic Ocean to allow a modest long distance swell to be generated:
It is currently heading in the direction of the arm of sea ice extending down into the East Siberian Sea, so I for one will be keeping a close eye on that area for the next few days.[Edit – September 20th]
The PIOMAS mid September gridded thickness data has been released so here is the “unofficial” Arctic sea ice thickness map for September 17th:
The volume graph is now rising, so barring any unanticipated surprises the (unofficial!) 2022 volume minimum was 5,060 km³ on September 13th:
Further news is now available on the October open thread.