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 2006-2009. 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.
August 5th 2010
Despite weather conditions that have slowed down the rate of Arctic sea ice melt in the weeks that matter the most, 2010 has doggedly persisted and is still clinging on to that second place in the great ice melt race. Weeks and weeks of winds blowing from the North and stalling of the Beaufort Gyre have spread the ice pack out over the Arctic Ocean, leading to 'holes', patches of relatively low ice concentration, in the interior of the pack. If these holes get any bigger, we might witness the separation of areas with multiyear ice from the central ice slush. I wouldn't be surprised if that was a first in the satellite era.
Whereas trends on most area graphs (such as this one from IJIS) have turned sideways, extent melt rate seems to have picked up in the last week. For the last two days of the previous SIE update melts of around 80K were reported and this trend has continued. For August 1st we even witnessed a small century break of 102,500 square km, the 11th of this season. In the days after that the consecutive reported melts were 88,281 for August 2nd, 76,250 square km for the 3rd and today's final reported number came in a bit lower after a 21K upwards revision: 61,719 square km.
2010 has been increasing its lead over 2009 and is so far managing to keep 2008 at a relatively safe distance of over 300K square km. 2007 had a few century breaks in a row during this period, but unlike 2008, that will keep sprinting well into September, it is going to run a bit out of steam next week. Still, it has a huge lead of almost 600K square km over 2010, so it makes no sense to start speculating as of yet.
The current difference between 2010 and the other years is as follows:
2006: -286K (37,697)
2007: +592K (57,041)
2008: -315K (70,333)
- 2009: -177K (48,654)
The average daily melt for the month of August is between brackets. 2010's average daily melt for August is currently 82,188 square km per day, but it is bound to go down as the month progresses.
And here's the IJIS sea ice extent graph:
The trend on the Cryosphere Today sea ice area anomaly graph has been going up and down and is currently more or less holding steady around -1.5 million square km compared to the 1979-2008 mean. The Arctic Basin as well as the East Siberian Sea are continuing their decline, slowly but steadily. Here's the anomaly graph:
It's bit premature to tell, as these weather forecasts change continually, but it looks as though weather conditions might switch to ice melting/transporting/compacting conditions in about five days from now. Both the European Centre for Medium-Range Weather Forecasts (ECWMF) and NOAA's Global Forecast System (GFS) - go to Wetterzentrale, click on the weather forecast models on the left and choose Northern Hemisphere 500 hPa SLP or Bodendruck - are forecasting a big high pressure system over the Beaufort, a key condition for the positive Arctic Dipole Anomaly:
I'm not seeing the same highs yet on this forecast map put out by Unisys, which is based on the GSFx model (perhaps one of the commenters can tell me if that's the same model as the one by GFS):
If this high starts developing for real I believe this would entail the Arctic Oscillation shifting to a negative phase. Right now it is still quite on the positive side, as we can see on NOAA's AO Index, but we should keep an eye on it the coming week:
Let's wait and see if the in situ melting and holes in the interior of the ice pack get replaced by big winds, big waves and thus ice melting, compaction and transportation. If the ice is as thin as some expect, things might get spectacular. Well, at least, the clouds will subside and we gain a better view of the Passages and other areas of interest.
TIPS - Other interesting blog posts and news articles concerning the Arctic and its ice:
A HUGE chunk of ice has broken of the floating ice tongue in front of Petermann Glacier. Patrick Lockerby has the details.
Ron Lindsay, scientist at the University of Washington's Polar Science Center, has updated his prediction for Total Ice Extent in September: 3.7 +/- 0.3 million square kilometers. That's low.
ClimateProgress has a new summary of current conditions in the Arctic.
Our modern Arctic heroes from Norway are sailing north along the Yamal Peninsula. Perhaps they can take some trees with them and deliver them in Canada after they have sailed through the Northwest Passage. They have encountered the first ice floes (from a distance) in the Kara Sea.
Lucia at the Blackboard has reported the results for her July NH Sea Ice betting pool. No new betting pool for August as of yet.