Strong Temperature Increase and Shrinking Sea Ice in Arctic Alaska

Barrow, the most northerly community in Alaska, observed a warming of 1.51°C for the time period of 1921- 2012. This represents about twice the global value, and is in agreement with the well-known polar amplification. For the time period of 1979-2012, high quality sea ice data are available, showing a strong decrease in sea ice concentrations of 14% and 16% for the Beaufort and Chukchi Seas, respectively, the two marginal seas bordering Northern Alaska. For the same time period a mean annual temperature increase of 2.7°C is found, an accelerated increase of warming over the prior decades. Looking at the annual course of change in sea ice concentrations, there is little change observed in winter and spring, but in summer and especially autumn large changes were observed. October displayed the greatest change; the amount of open water increased by 44% and 46% for the Beaufort and Chukchi Seas, respectively. The large amount of open water off the northern coast of Alaska in autumn was accompanied by an increase of the October temperature at Barrow by a very substantial 7.2°C over the 34 year time period. Over the same time period, Barrow's precipitation increased, the frequency of the surface inversion decreased, the wind speed increased slightly and the atmospheric pressure decreased somewhat.