Investigation of North Pacific sea ice anomalies in the context of atmospheric and oceanic variability

Abstract

This study investigates the main mode of variability in North Pacific sea ice and examines the relationship between sea ice concentration and northern hemispheric climate variability for the period 1968-1997. Through empirical orthogonal function (EOF) analysis, correlations, and composite analysis, it was found that the seesaw pattern (first EOF of wintertime sea ice concentrations) between ice concentrations in the Bering Sea and the Sea of Okhotsk, generally used to characterize North Pacific sea ice, does not adequately address variability in the Sea of Okhotsk. Relationships between the sea ice dipole and the large-scale circulation were investigated and were found to change with the 1977 and 1989 regime shifts in the North Pacific climate. Before 1977 the sea ice dipole is strongly related to tropical variability while after 1977 the dipole is more strongly related to mid-latitude variability.