Downward trend continues …
By Summit Voice
FRISCO — With the spring equinox approaching, Arctic sea ice is nearing its maximum seasonal extent for the year, and the National Snow and Ice Data Center is reporting that there is no sign of any significant rebound in ice extent from the record-low levels of the last couple of years.
The average February Arctic sea ice extent has been declining at rate of 2.9 percent per decade since 1979, resulting in an overall decline of more than 1.57 million square kilometers (606,000 square miles) from 1979 to 2013. Read the full NSIDC report here.
Even though ice extent in February grew at an above-average pace, gaining 766,000 square kilometers, the monthly average extent remained about 1 million square kilometers below the 1979 to 2000 average. At 14.66 million square kilometers, it was the seventh-lowest extent in the satellite record. According to the NSIDC, sea ice extent has remained below 15 million square kilometers every winter since 2004 with the exception of 2008. The ice cover was below average everywhere but the Bering Sea, where it has consistently been above average the past few years.
Above average temperatures prevailed across the Atlantic sector of the Arctic, especially near Iceland and in Baffin Bay. Temperatures were lower than average by 2 to 6 degrees Celsius north of Greenland and the Canadian Archipelago, and in the Beaufort, Chukchi and East Siberian seas, driven by anomalously low sea level pressure over Alaska and Canada. The dominant feature of Arctic sea level pressure for February 2013 was unusually high pressure over the East Greenland and Barents seas, consistent with a predominantly negative phase of the Arctic Oscillation.
Arctic ice researchers also noted fracturing across a big area of the ice off the coast of Alaska and Canada, extending from Ellesmere Island in the Canadian Arctic to Barrow, Alaska. The spiderweb cracks may have been caused by a storm that passed over the North Pole in early January, pushing the ice away from land.
Similar patterns were observed in early 2011 and 2008, but the 2013 fracturing is quite extensive. More information on the cracking is posted on the Arctic Sea Ice Blog).
At the other end of the Earth, Antarctic sea ice extent may have passed its summer minimum in late February, but the NSIDC reports that sea ice remained quite extensive during the Austral summer, especially in the Ross Sea region. Overall, Antarctic sea ice extent was second-highest in the satellite record.