On the observed connection between Arctic sea ice and Eurasian snow in relation to the winter NAO

Abstract

Many recent studies reveal that sea ice concentration (SIC) in the eastern Arctic and snow cover extent (SCE) over central Eurasia in late autumn are potential predictors of the winter North Atlantic Oscillation (NAO). We used maximum covariance analysis (MCA) to investigate the links between autumn SIC in the Barents-Kara Seas (BK) and SCE over Eurasia (EUR) with winter (DJF) sea level pressure in the North-Atlantic-European region over 1979-2015. The most significant covariability mode for SIC/BK appears in November. The MCA modes for SCE/EUR are not statistically significant, but November shows higher correlation and some statistically significant anomalies preceding the winter NAO. Changes in temperature, specific humidity, SIC/BK and SCE/EUR in November are modulated by an anomalous anticyclonic circulation over the Ural-Siberian region that appears to be a precursor of the winter NAO.