The area of Arctic sea ice in September, a little bit not to get to the historical low

The average area of Arctic sea ice in September fell to 4.61 million square kilometers, 310 square kilometers over a record low in 2007, experts told the National Information Center for Snow and Ice (NSIDC) USA.

Earlier in September, has been fixed annual minimum ice area for the region: September 9, the figure was 4.33 million square kilometers. This is the second lowest result in the history of satellite observations after 2007, when the annual minimum, made on September 16, was 4.17 million square kilometers.

The average area of Arctic sea ice in September 2011 was 2.43 million square kilometers less than the historical average for 1979-2000. As the experts of the center, as in previous years, the Arctic route was free of ice, and the Northern Sea Route, is fully open to the middle of August, and remained so to the end of September.

"While the ice melt season in 2011 started rather slowly, in June the rate of reduction of its area is increased. Ice quickly, almost two times faster than the average for the entire observation period, retreated in the Kara and Barents Seas. Rapid melting continued in the first half of July, but then the process has slowed down because of the traffic area of low pressure in the central part of the region. By late July, sea ice was slightly higher than the corresponding figure of 2007 "- the report says NSIDC.

Employment specialists say that after the September 9 minimum ice began to recover fairly quickly, and as of 1 October, the average five-day sea ice was more than 5 million square kilometers.

Weather conditions in 2011 compared to the "record" 2007 was less extreme in terms of melting ice: four years ago, the air temperature in the area of the Beaufort Sea and the Chukchi Sea was five degrees Celsius above normal, while this year it was close to it. In addition, there were less significant surface temperature anomalies in the Arctic Ocean.

Experts stress that the ice in the Arctic continues to "younger" in March 2011 to the ice age of about one to two years accounted for 80% of the total area of ice cover, while in 1980-2000, the figure was an average of 55%.

False record

In early September, the specialists of the University of Bremen, based on data NASA satellite "Aqua", estimated that the area of Arctic sea ice in early September fell to 4.24 million square kilometers — the minimum value for that date for the entire observation period. However, experts and Russian Hydromet NSIDC not confirmed this information.

As noted in the American space agency, managing satellite "Aqua", the differences in the estimates of the minimum caused by the fact that, in assessing the dynamics of Arctic ice are two similar, but not identical measure.

"Although the ice cover (sea ice extent, a figure that uses NSIDC — Ed.) Fell below the record of 2007, sea ice (sea ice area — Ed.), Which evaluates the microwave radiometer satellite" Aqua ", approximately 10 days early September was actually less than 2007 levels, "- said in a NASA.

Agency specialists explain that sea ice is the actual surface area covered by ice, whereas the calculation of the area of ice cover on the methodology section NSIDC grid observed by satellite, is recognized completely covered with ice, on the ice if it accounts for at least 15% of the .

"The easiest way to understand the difference between them, imagining a square piece of cheese with holes. Indicator square cheese is equal to the area of the square minus the area of the holes, whereas the number of cheese cover — the entire area of the square," — said in the notes on the website NSIDC.

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