Characteristics of the Kamchatka Current Eddies

Abstract

The characteristics of eddies in the Kamchatka Current from its source in the Bering Sea to Paramushir Island south of Kamchatka are considered for the first time. The Kamchatka Current in the Olyutorsky Bay contains anticyclonic eddies having a cold core of low salinity with the diameter to 90 km and to 120 km located south of the Avacha Bay. The characteristics of the Kamchatka Current eddies are determined using Terra and Aqua satellite data and the data of Argo buoys and surface drifters. The maximum velocity of a surface current in an eddy south of Kamchatka reaches 1 m/s. Satellite observations demonstrate that such eddies propagate in the Bering Sea from east to west to the latitude of Karaginsky Island and further to southwest to the Kamchatka Strait. The thermohaline characteristics of the eddies located in the northwestern Bering Sea and south of Kamchatka are close to each other. At the same time, during 1990–2017, in the eddy core temperature rose by 1°C and salinity decreased by 0.5 psu. Salinity anomalies at minimum temperature were significant in 1990 and 2004–2006 and were small in 1996–1998 and 2015–2016. The most probable reason for the salinity variations at minimum temperature is that the intensity of tidal mixing varies in the lunar nodal cycle.