Impact of synoptic processes and river discharge on the thermohaline structure in the east Siberian Sea shelf

The thermohaline structure of waters in the East Siberian Sea coastal zone in September 2000, 2003, and 2004 is investigated. It is found that the spatial variability of thermohaline characteristics was determined by various synoptic conditions observed over the East Siberian Sea during the summer-autumn season and by fluctuations in the river discharge. In surface layers, plume fronts are identified. Under conditions of cyclonic atmospheric circulation of 2003, fresh waters spread as a narrow jet along the coast. During anticyclonic circulation of 2004, some meridional fronts existed. Horizontal gradients of thermohaline characteristics were 0.01–0.02°C/km and 0.03–0.07 psu/km off the Indigirka River and 0.02–0.03°C/km and 0.06–0.09 psu/km near the Kolyma River mouth being an order of magnitude less than the vertical ones. The stratification of coastal waters was amplified as the river and ice-melted runoff increased. In the thermohalocline, the average Brunt-Väisälä frequency was 0.042 s^?1 (in 2000), 0.068 s^?1 (in 2003), and 0.074 s^?1 (in 2004).