The National Snow and Ice Data Centre has just released its August analysis of Arctic conditions in the past month. Here are some excerpts:
Average ice extent for August was 5.98 million square kilometers (2.31 million square miles), 1.69 million square kilometers (653,000 square miles) below the 1979 to 2000 average, but 620,000 square kilometers (240,000 square miles) above the average for August 2007, the lowest August in the satellite record. Ice extent remained below the 1979 to 2000 average everywhere except in the East Greenland Sea near Svalbard.
The minimum ice extent for the year will probably occur in the
next two weeks. NSIDC scientists are closely monitoring conditions and
will report the minimum when it occurs.
(...)
At the end of August, ice extent had fallen to the fourth lowest in the satellite record, behind the seasonal minima recorded for 2007, 2008, and 2009. On September 3, ice extent fell below the seasonal minimum for 2009 to claim third lowest on record, with perhaps one to two weeks left in the melt season.
The daily rate of decline for August was 55,000 square kilometers (21,000 square miles) per day, close to the 1979 to 2000 average of 54,000 square kilometers (21,000 square miles).
(...)
In August, a pattern of higher than average pressure over the northern Beaufort Sea and lower than average pressure over the Siberian side of the Arctic replaced the stormy and cool weather conditions that persisted through July. This atmospheric pattern, known as the dipole anomaly, brought relatively warm southerly winds into the Beaufort and Chukchi seas, where air temperatures were 1 to 3 degrees Celsius (1.8 to 5.4 degrees Fahrenheit) above normal for the month of August. The warmth enhanced melt in the region, and southerly winds contributed to ice loss by pushing the ice edge northward. This pattern is similar to the pattern at the end of the 2007 melt season, but not as pronounced.
Continue reading at NSIDC.
"The minimum ice extent for the year will probably occur in the next two weeks."
Anyone think they are going out on a limb here? 2005 had minimum on 22 Sept and 2007 had minimum on 24th Sept. 2 in 5 failed to be within 2 weeks of 7 Sept. A 60% probability might be enough to say "probably". However, is it as high a probability as 60% if
1. The trend is towards later dates.
2. There has been high melt early in the season allowing more time for more heat to be absorbed by ocean and this is likely to be significant factor in date of onset of freeze though weather is clearly the dominant effect.
3. Current and forecast weather conditions??
4. High recent rate of extent reduction.
5. Large PIPS arrows in southerly direction in Fram straight encouraging export and spreading. (note spreading does not necessarily lead to extent reduction 70% coverage to 60% coverage would be an increase in extent but 20% to 10% is a reduction in extent.)
6. Large PIPS arrows in general suggesting minimum is not close. (I am far from convinced that Neven has examined sufficient years to suggest this and I don't think you can easily extrapolate hypotheses from a small number of years. Hence I am putting this down at number 6.)
or am I just seeing all the things that alarmists see and failing to see things pointing in the other direction?
Maybe I should ask the author if they want to bet on it?
Posted by: Gas Glo | September 08, 2010 at 00:26