The Abrupt Decrease of the Sea Ice over the Southern Part of the Sea of Okhotsk in 1989 and Its Relation to the Recent Weakening of the Aleutian Low

Abstract

We investigated the interannual variation of the sea ice over the Sea of Okhotsk by using radar observation data and gridded ice-coverage data for the years 1969-1994. It became evident that the abrupt decrease of sea ice over the southern part of the Sea of Okhotsk occurred in 1989, and that this reduced-ice condition has continued since then. In addition, the winter time Aleutian low has abruptly weakened since 1989. According to the lag-correlation analysis, this weakening has brought about the reduction in extent of the ice-coverage.