During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2014 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.
September 1st 2015
Look at the sea ice concentration animation at the top right. Notice how the final frame suddenly is whiter than the preceding frame? That's a sign that we have entered the final phase of the melting season, when temperatures drop and melt ponds within the ice pack freeze over again. Sea ice concentration goes up, and the NSIDC SIC map becomes whiter.
But the Pacific side of the Arctic is still bluish. During the past two weeks the disintegration of that part of the ice pack has continued, spurred on by a late cyclone that further stressed the region (see special blog post on the matter) and increased the area that consists of a mix of ice floes and open water. The compaction potential of this region will probably decide where this melting season will end up on the various sea ice area and extent graphs.
And this end result still holds interest, because - somewhat surprisingly - the 2015 melting season could still achieve a top 3 minimum. Surprising, because the melting season started out with more volume, more multi-year ice, saw little and late preconditioning during May and June, and - despite a killer July - there has been relatively little transport and compaction this year.
With melting momentum mostly out of the picture now, it all comes down to compaction.
Sea ice area (SIA)