Climatic and atmospheric teleconnection indices and western Arctic sea ice variability

This study examines the sea ice cover minima in the western Arctic in the context of several climatic mechanisms known to impact its variability. The September latitude of western Arctic sea ice is measured along 11 equally-spaced longitudes extending from 176o W to 126o W in the Chukchi and Beaufort Seas, 1953-2010. Indices of seasonal atmospheric and oceanic teleconnections and annual mean Northern Hemisphere temperatures (NHT) and CO2 concentration are orthogonalized using rotated principal component analysis, forming predictors regressed onto the sea ice latitude data at each longitude using stepwise multiple linear regression. Prior to 1998, small amounts of September ice edge variance are explained by teleconnections such as the Arctic Dipole, Arctic Oscillation, and Pacific-North American Pattern. NHTs begin explaining large amounts of ice edge variance starting in 1998. For the 1953-2010 period, up to 68% of the ice edge variance is explained at 161 degrees W in the Chukchi Sea, mostly by NHTs. With the exception of the three easternmost longitudes (136-126 degrees W), the teleconnections and NHTs explain over 50% of the regional ice edge variance. Increases in both NHTs and ice retreat since the mid-1990s account for the large explained variances observed in regression analyses extending into recent years.