This is the next in a series of diaries on the state of Arctic sea ice (and other topics as warranted) in memory of Johnny Rook, who passed away in early 2009. He was the author of the Climaticide Chronicles.
This week, the climate news diary I usually do will be out a little early, since I'm writing up the more general one for Patriot News Clearinghouse today. So the latest news may be a bit briefer than usual. First, the Barrow AK Arctic Sea Ice webcam from this a.m. (5:17 Alaska Time). Weather is nasty as one would expect ... but actually a shade warmer than normal.
The rest of the Arctic story this week below.
Arctic Weather: Week ending 9/2/10
Some pretty intense short-range climate anomalies continued in the Arctic Ocean basin last week. Temperatures were above normal once again on the Siberian and North American sides of the Arctic, and below normal in European Russian and Scandinavian sections. Warm anomalies were as much as 11°F and cool anomalies as much as 7%deg;F.
925-hPa Temperature Anomalies: 27 Aug. - 2 Sept. 2010
The sea level pressure anomalies show a strong low was on the central Asian Arctic coast with a 15-hPa (millibar) pressure anomaly there. The winds were anomalously strong circulating counterclockwise around this low. High pressure was over the North Atlantic part of the Arctic, over Iceland.
Mean Sea Level Pressure Anomalies: 27 Aug. - 2 Sept. 2010
Winds near the surface (10 meters) were up to 21 mph stronger than normal between the anomalous low pressure just north of central Asia and the anomalously high pressure over Iceland. These wind anomalies are annotated in the graphic below, and were important in the evolution of the sea ice pack in the Arctic.
10-meter Wind Anomalies: 27 Aug. - 2 Sept. 2010
Arctic Sea Ice
These graphics below reflect the information from 3 September 2010. The data from the Japan Aerospace Exploration Agency (JAXA) just came in for the 4th, however, and the latest sea ice extent has now dropped below 5.2 million km2. This puts us below last year at the third lowest sea ice extent behind the record minimum in 2007 and the second lowest in 2008 (these both well below 5,000,000 km2.
Arctic Sea Ice Extent: 3 September 2010
The Arctic sea ice concentration map continues to show the ice is, except along the North American/Greenland coast and poleward, in a relatively fragile state, with large areas of 40% concentration or less (these areas are in shades of blue).
<Arctic Sea Ice Concentration: 3 September 2010</strong>
Both the Northwest and Northeast Passages are open once again this year.
What's Next
Sea ice minimum can be anywhere from now to three weeks from now. In fact, the sea ice extent had stopped falling for a couple days this week as the near-surface winds were shifting temporarily from the previous week's configuration as a strong cyclone moved into the Bering Sea and then the Arctic Ocean. The last two days have shown sea ice extent decreases in excess of 50,000 km2, a large value for this time of year. The fragility of the ice and the strength and direction of the winds may result in large changes over the next week or two. Not sure if this year will become the third year since 1979 with sea ice minimum of less than 5 million km2 ... we have about 190,000 km2 to go.
Stay tuned.