March ends a most interesting winter in the Arctic
6 April 2016 (NSIDC) – Low Arctic sea ice extent for March caps a highly unusual winter in the Arctic, characterized by persistent warmth in the atmosphere that helped to limit ice growth. Above-average influx of ocean heat from the Atlantic and southerly winds helped to keep ice extent especially low in the Barents and Kara seas. Northern Hemisphere snow cover for both February and March was also unusually low Sea ice extent reached its seasonal maximum on March 24 of 14.52 million square kilometers (5.607 million square miles), barely beating out 25 February 2015 for the lowest seasonal maximum in the satellite record. Arctic sea ice extent averaged for the entire month of March 2016 was 14.43 million square kilometers (5.57 million square miles), the second lowest in the satellite record. This is 1.09 million square kilometers (421,000 square miles) below the 1981 to 2010 average extent, and 40,000 square kilometers (15,000 square miles) above the record low monthly average for March that occurred in 2015. At the end of the month, extent remained well below average everywhere except in the Labrador Sea, Baffin Bay, and Hudson Bay. Ice extent was especially low in the Barents and Kara seas. Because ice extent typically climbs through the first part of March until it reaches its seasonal maximum and then declines, the daily average ice growth rate for the month is typically quite small and is not a particularly meaningful number. This year’s seasonal maximum, while quite low, also occurred rather late in the month. Very early in the month, extent declined, raising anticipation that an early maximum had been reached. However, after a period of little change, extent slowly rose again, reaching the seasonal maximum on March 24. March of 2016 saw unusually warm conditions over nearly all of the Arctic Ocean. Air temperatures at the 925 hPa level (about 3,000 feet above the surface) were typically 2 to 4 degrees Celsius (4 to 7 degrees Fahrenheit) above average over the Arctic coastal seas, with larger positive departures compared to average nearer the Pole (4 to 8 degrees Celsius or 7 to 14 degrees Fahrenheit). This was associated with a pattern of above-average sea level pressures centered over the northern Beaufort Sea north of Alaska, and below-average pressures over the Atlantic side of the Arctic, especially pronounced over Baffin Bay and Davis Strait. Through March, the Arctic Oscillation Index bounced between moderate positive and negative values. Arctic sea ice extent averaged for March 2016 was the second lowest in the satellite record. Through 2016, the linear rate of decline for March extent is 2.7 percent per decade, or a decline of 42,100 square kilometers (16,200 square miles) per year. [more]
