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Messages - SparkyIce

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Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: September 15, 2020, 07:50:55 PM »
As a long time lurker and persistent reader of this forum, I think it appropriate at this time to especially thank Oren, Juan C. Garcia, Frivolousz21, Jim Hunt, Born From The Void, Aluminum, A-Team, ArcticMelt2, Gerontocrat, and other participants on the ASIF for their continued outstanding analyses of the Arctic environment.  I also want to thank Neven for making this all possible as well. For people like me publishing these analyses in the concise and straightforward manner is a godsend for us.  The lack of garbage and political interference is indeed refreshing. So, "Thank You" to everyone.....

VaughnAn

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Arctic sea ice / Re: The 2020 melting season
« on: August 19, 2020, 08:47:45 PM »
I am a very non-science based observer, but have lurked here for about 5 years with a few posts. The following may not hold water but what the hey -

I feel that the last fifteen years have truly changed the nature of arctic sea ice, but a lot of the systems and analysis was established as 'fact' before that change really manifested and to some degree it has yet to adjust. Pre-2007 the arctic sea ice remained 'land fast' even at minimum, but by 2012 the only connection to land was Greenland and the CAA islands. Since then even that connection has become intermittent and this year it has been almost non-existent for most of the summer.

The importance to me of the above is that pre2010 arctic ice movement except on the periphery was slow and measured - Ice forming on the Asian side took years to migrate toward Greenland where it either eventually exited the Fram/Nares or started to circle back toward Asia. Ice in the Beaufort got trapped into the gyre and circled back toward Greenland as multi-year ice.

This year looking at the speed with which Polarstern transversed from Asia to the Fram is a perfect illustration of the speed of arctic ice in this new era. Meanwhile no one really looks at the gyre because it is no longer a trap in which ice rotates year after year, but a transportation from the north of the CAA to oblivion for the remnants of 'older' ice. And with Greenland giving up its function as an anchor for the pack the other remnants of 'older ice' are moving towards the CAA and thence to their oblivion. The gyre is no longer tied to the Beaufort as peripheral ice movement but has in effect expanded to include the whole of the pack not destined for the Fram/Nares/Barents exit ramps.

The other aspect of this ice speed and the increased melt rate during melting seasons is that 'older' ice (I use quotes for a reason) is really limited to two year ice with maybe a few chunks interspersed that are older or formed from glaciers/collapsed ice shelves. Even the ice that is technically heading into a third winter this year has suffered so much top and bottom melt in its two summers that only a tiny fraction will be any thicker than the typical first year ice of 2000. And specific to the ice above Greenland - while this year may be extraordinary, the open water has been present for most of the past number of years so it was already fragmented and held together with a matrix of weaker ice. The disappearance of that ice was waiting for the right winds and temperatures and isolation which 2020 has provided.

Back to that second paragraph above - with a strong pack, slow movement and a melt season limited to the peripheral edges, extent with its simpler calculation was the best measure and quite accurate. As movement and melt increased, and the pack easily fragmented, area has become more accurate even with the calculation margins of error. The historic 'record' has validity, but at some point the extent measure becomes less and less relevant to the real life conditions. Additionally, volume measures (Piomas and others) are grounded in a 'solid pack' view of arctic ice and I believe struggle to deal with the 'real world' condition of the pack where 'thick ice' is actually a patchwork of loose flows held together by new and thin ice. Images from Polarstern seem to make this abundantly clear.

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