The mp4 below shows 84 days of the fall freeze season, from Oct 01 to Dec 23. Here SMOS was used at 132.24% enlargement to provide masks for land, open water and thin ice as Ascat alone has distracting artifacts there especially early in the season.
Note a white band of ice (an extended virtual buoy for tracking purposes) forms early on in the northern Laptev at the FYI/SYI edge (as it did last year) and will likely remain trackable until May. The overall pattern of ice movement here has been a squash towards Greenland and the CAA.
The physical explanation for the hundreds of km of white band remains elusive. Efficient scattering from low dielectric near-surface ice is typically seen in older ice that has lost its brine pockets. However Ascat's active microwave beam can also be reflected back from crumpled ice with right-sized debris particles. How and why this would form at the edge of SYI perhaps may require strong 'offshore' winds piling up newly formed ice. The area is inaccessible to ships and the feature may not be apparent at visible or infrared wavelengths anyway.
Other stably advecting Ascat features such the large dark elongated patch in the north Beaufort also lack interpretation. This area froze up very rapidly in patches per Smos-Smap and so may have incorporated extra near-surface salinity which would indeed make it appear darker.
Note too the unusual mid-December surge of ice west across the Chukchi to the shores of Chukotka; usually western Alaskan ice originating northeast of Banks Island turns north upon reaching the eastern Chukchi, perhaps riding Bering Strait inflows.
This can be attributed to the persistent anti-cyclone over the period 08-24 Dec 2020 that has brought clear skies and with it excellent Suomi band 15 views of heat loss from leads and their motion (
https://go.nasa.gov/2KPeWlH opens to a good palette set-up). As the large diameter anti-cyclone wandered across the Arctic Ocean towards the Kara side, winds often blew in the
opposite direction of that needed for a return Gyre.
Export out the Fram has picked up but has the odd oblique meridional surge is from the central CAB rather than the usual zonal route between the pole and the SZ-FJL-Svalbard. This could have the effect of exporting older thicker ice but this year, as witnessed by the Polarstern, the ice between Greenland and the pole did not fit that description in September.
