Arctic sea ice coverage variable, ends May below average: data center
May sea ice melts "slightly faster" than the long-term average
After reaching near-average levels in late April, sea ice extent in the Arctic declined rapidly during the early part of May, says the Colorado-based National Snow and Ice Data Center in its recent report on sea ice coverage in the Arctic.
The rest of May saw a slower rate of decline, it said.
Arctic sea ice extent for May 2012 averaged 13.13 million square kilometres. That’s still 480,000 sq. km. below the 1979 to 2000 average extent.
May sea ice extent was 550,000 sq. km. above the record low for the month, which happened in the year 2004.
During May, the Arctic as a whole lost 1.62 million sq. km. of ice, which was 180,000 sq. km. more than the 1979 to 2000 average.
The average daily rate of ice loss was 52,000 sq. km. per day, which was “slightly faster” than the long-term average of 46,000 sq. km. per day.
However, the rate of ice loss for the month was composed of two distinct periods, the NSIDC said: a rapid loss of ice during the first part of the month, followed by near-average rates during the latter part of the month.
Air temperatures for May were higher than usual over the central Arctic Ocean and the Canadian High Arctic, the NSIDC noted.
This year, NASA’s IceBridge Arctic sea ice program, which uses air-borne instruments to measure ice thickness, collected data in late March and early April, and provided data to NSIDC to validate its information from satellites.
The data, collected from the North American side of the Arctic, show thick ice north of Greenland due to wind and ocean current patterns piling ice into thick ridges.
In the Beaufort Sea, the offshore ice is fairly thin, one to two metres thick, indicative of first-year ice.
Such thin ice will be prone to melt out completely this summer, said the NSIDC.