I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2005-2009. The IJIS graph is favoured by almost everyone, probably because it looks so nice compared to other graphs (like the one by Arctic ROOS, the University of Bremen and the Danish Meteorological Institute). All the years have a nice colour of their own which makes it easy to eyeball the differences between trends. Most of the betting on minimum SIE is based on the IJIS data. NSIDC has a good explanation of what sea ice extent is in their FAQ.
September 19th 2010
I think the melting season is over, in the sense that minimum extent has been reached once and for all:
I could be wrong of course (there's a caveat for ya) and if I am I'll be in good company. It is definitely possible that the arm in the East Siberian Sea gets amputated some more or some of that spread out ice on the other side of the ice pack gets pushed back and compacted. In that case minimum extent might dip down a little further. But maybe not. Like I've said many times before: when you see a PIPS ice displacement map such as the one below at this (far out) point in the season...
...you know that the end of extent declines has been signalled. Small arrows are deadly at this point. The freeze-up will seize this chance and trump warm SSTs and compacting winds, especially since the weather forecast is projecting high-pressure areas: exit. More of that at the end of this update.
The current difference between 2010 and the other years is as follows:
- 2005: -572K
- 2006: -1060K
- 2007: +532
- 2008: +95K
- 2009: -535K
A virtual tie with 2008, I'd say, as far as extent is concerned.
Artful Dodger sent me some more statistics for this month. It shows the average daily and total extent decrease for September until minimum extent compared to other IJIS years. 'Sep Dec' is the September cumulative decrease in SIE, computed as follows (SIE on date of minimum SIE) - ( Aug 31 SIE ):
Year Sep Avg Sep Dec 2010 Diff%
2010 -28,658 515,781 515,781 0.00%
2007 -14,688 352,500 515,781 46.32%
2005 -15,263 335,782 515,781 53.61%
2008 -35,781 322,031 515,781 60.17%
2003 -13,898 250,157 515,781 106.18%
2009 -15,180 197,344 515,781 161.36%
2006 -13,784 192,969 515,781 167.29%
2002 -20,885 187,969 515,781 174.40%
2004 -12,131 133,437 515,781 286.54%
Here's the IJIS sea ice extent graph:
Cryosphere Today sea ice area has been going up quite steeply in the past few days, even compared to the 1979-2008 mean. This must be due to all the holes in the central ice pack freezing up and of course freezing at the edges as well. The anomaly has therefore gone up as well and currently stands at -1.509 million square km:
The combination of extent decreases and area increases has the 2010 trend line of our CAPIE (Cryosphere area per IJIS extent) graph going through the roof. It went from 62.6% in the last SIE update to 68.8%:
When all is over and done, there is nothing left for me but to show the ECMWF weather forecast for the coming days:
In 2-3 days from now a high will try to reform over the Beaufort Sea, but I think that will be too late for a return of the conditions that brought us the second extent minimum. So long, sea water. Welcome back, sea ice.
TIPS - Other interesting blog posts and news articles concerning the Arctic and its ice:
Patrick Lockerby keep us up-to-date with regards to the Petermann/Lockerby Ice Island: Petermann's Progress.
From January 23-28 there will be another Arctic Frontiers conference in Tromsø, Norway, with the title “Arctic Tipping Points” (how appropriately timed). Here you can read some of the abstracts of presentations of keynote speakers.
Gareth Renowden from the Hot Topic blog talks some more about the double dip we experienced in the past week.
The Norwegians (and Russians) have practically made it through the Northwest Passage!