Warming in the Nordic Seas, North Atlantic Frankenstorms and Thinning Arctic Sea Ice

Abstract:

Arctic sea ice over the last few decades experienced a significant decline in the coverage both in the summer and winter. The currently warming Atlantic Water layer has a pronounced impact on sea ice in the Nordic Seas (including Barents Sea). More open water combined with prevailing atmospheric pattern of airflow from the Southeast and persistent North Atlantic storms like a recent extremely strong one, Frank in December 2015 and a 'Christmas' storm in December of 2016 lead to increased energy transport to the high Arctic. Each of these storms brings sizable anomalies of heat to the high Arctic, resulting in significant warming and slowing down of sea ice growth or even melting. Our analysis indicates that the recently observed sea ice decline in the Nordic Seas during the cold season around Svalbard, Franz Joseph Land and Novaya Zemlya and the associated heat release from open water into the atmosphere contributed significantly to the increase in the downwelling longwave radiation throughout the entire Arctic. Added with other changes in the surface energy budget, this increase since the 1960s to the present is estimated to be at least 10 W/m2, which can result in thinner (up to 15 cm or more) arctic ice at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of arctic sea ice. Sea ice decline resulting from the warming in the Nordic Seas has also widespread implications for winter weather in the Northern Hemisphere.