Water Circulation in the Kuril Basin of the Okhotsk Sea and its Relation to Eddy Formation

Abstract

This paper describes the water circulation in the Kuril Basin and its role in the formation and seasonal variation in intensity of the large anticyclonic eddies which occur in the basin. Oceanographic data for the period June 1977 through June 1979 suggest that these eddies develop in summer and decay in winter. In summer, the eddy development is associated with a deepening of the isopycnals caused by the surface flow of the Soya Warm Current over the basin, and the deep advection of cold, less saline, oxygen-rich water from Terpenia Bay and the eastern continental shelf of Sakhalin Island. In winter, the eddy decay is caused by surface cooling and convective mixing downward of the warm, saline surface water, which causes the isopycnals to rise and leads to an attenuation of the eddies. This combination of the summer influx of water into the region, and the fall and winter cooling of the eddies leads to the annual variation in eddy intensity.