The extent of melting in 2007 "caught pretty much everybody by surprise, because the retreat of the ice cover that summer was quite extreme," says Martin Jeffries, program officer and science advisor to the Office of Naval Research's Arctic and Global Prediction Program.
Despite the initial shock, however, the record melts of '07 and '12 arrived in the context of a persistent decline in summer sea ice throughout the 24-year satellite record.
The potential for a significant increase in maritime traffic in the Arctic basin each summer demands a better understanding of the ice cover and the factors that affect it in order to improve predictions.
Summer storms, for instance, can have a profound effect on the ice. Last summer provided a textbook example. A storm dubbed the Great Arctic Cyclone of 2012 moved into the central Arctic Ocean from Siberia Aug. 4 – the most powerful August storm on record for the Arctic Ocean. The storm packed winds of more than 30 miles an hour in some areas of the Arctic Ocean above the Pacific and lingered over the ocean for a few days before petering out.
For 10 days, the pace of ice loss accelerated, reducing the extent of summer ice by nearly 60,000 square miles. The heaviest losses appeared from the Beaufort Sea above Canada and Alaska west to the East Siberian Sea.
A team led by the University of Washington's Jinlun Zhang, a researcher with the university's Applied Physics Laboratory, analyzed the storm's impact via modeling studies.