During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Because of issues with data based on the SSMIS sensor aboard DMSP satellites, I mainly focus on higher-resolution AMSR2 data from the Japan Aerospace Exploration Agency (JAXA), as reported on the Arctic Data archive System website. I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.
September 10th 2016
It's that time of year when the melting season is drawing to a close and the Arctic sea ice pack is reaching its lowest size of the year, also known as the minimum.
This melting season was a strange one. After the mildest winter on record, a spectacular opening up of the Beaufort and Chukchi Seas made trend lines on graphs go extremely low even before the melting season had properly started. But then clouds moved in during the period when the Sun is at its peak, and solar radiation causes melt ponds to form on the ice pack, building up so-called melting momentum.
June and July were really cloudy, as cloudy as in rebound years 2013 and 2014, but this time around atmospheric conditions weren't accompanied by low temperatures on the ground and in the water. The warm winter, early opening up of the ice pack and the rapid melting of land snow cover, caused another kind of momentum, one of heat, that kept the melting going throughout.
And then in August, a massive storm that kept on re-intensifying (or maybe they were two separate storms), followed by a Dipole with a massive pressure gradient, battered the ice pack. Again, as in 2012, we've witnessed the detachment of one large piece of ice from the main pack. And now the 2016 melting season has reached 2nd place on almost all extent and area graphs out there.
You read it right, a melting season that saw mostly cloudy conditions during the sunniest period of the year (June-July-August) has beaten the 2007 melting season which went astonishingly low after weeks of ceaseless sunshine and a massive Beaufort Gyre, continuously compacting the ice pack, well into September.
But it looks rather unlikely that the 2016 melting season will end that late. The past few weeks have promoted massive ice dispersal, with large zones of low concentration near the Pole, and so there's a lot of compaction potential. But for compaction to happen, winds need to blow towards Greenland and the Canadian Arctic Archipelago, or else freezing temperatures start to dominate and all that open water within the ice pack and on its fringes starts to fill up with ice. The reverse is the case.
We can see that happen on this animation of Uni Bremen sea ice concentration maps of the past week:
The remnants of the now fully detached Wrangel Arm are still melting, compensating the ice growth elsewhere, but I'm pretty sure the minimum has been reached.
I will have a blog post with more images characterizing this melting season up later this week.