Satellite observations of the ice cover of the Kuril Basin region of the Okhotsk Sea and its relation to the regional oceanography

Abstract

For the period 1978–1982, this paper examines the nature of the sea ice which forms over the Kuril Basin of the Okhotsk Sea and describes the impact of this ice on the regional oceanography. The paper compares the oceanographic behavior during the heavy ice season associated with the cold 1979 winter with the behavior during the lighter ice years of 1980 and 1982. Examination of the oceanography in the Okhotsk and the adjacent Pacific shows that the early summer water column structure depends on the heat loss from the Okhotsk during the preceding ice season, the total amount of Okhotsk ice formation, and specifically the amount of ice formation in the Kuril Basin. Following the 1979 ice season, the upper 200–300 m of the Kuril Basin waters were cooler, less saline, and richer in oxygen than for the other years. This modification appears to be a process local to the Kuril Basin, driven by eddy‐induced mixing, local cooling, and ice melting. In the depths 300–1200 m, the water modification is caused by the advection of water from the northern Okhotsk. For 1979, this deeper water is also less saline, colder, and richer in oxygen than for the lighter ice years. The water modified in the Okhotsk enters the adjacent North Pacific through the Bussol' Strait, where for 1979 the adjacent waters are also cooler, less saline, and richer in oxygen down to a depth of 1000 m than for the lighter ice years.