Possible causes of decreasing cloud cover in the Arctic winter, 1982–2000

Abstract

Satellite and reanalysis datasets show a decrease in wintertime (Dec., Jan., Feb.) cloud cover over most of the Arctic Ocean from 1982 to 2000. Concurrently, wintertime moisture convergence has decreased significantly over the Nansen Basin and parts of the Barents and Kara Seas (NBK; 75–90°N, 45–90°E). Over this region, correlation coefficients between monthly anomalies in the satellite‐derived cloud cover and moisture convergence in the cold season are large and statistically significant. This reduction in moisture convergence results in a decrease in cloud formation due to weakening cyclone activity over the NBK region. Reduced cloud amount over this area leads to decreased cloud cover over the entire central Arctic because less cloud is advected to other regions. The same mechanism has been observed over northeastern Russia and the Bering Strait area (RBS; 65–75°N, 150–200°E) and is therefore an additional, and perhaps more important, control over cloud cover in the Chukchi/Beaufort Seas and the Laptev Sea region.