Osobennosti sezonnoy izmenchivosti gidrologicheskogo rezhima bukhty Novik (ostrov Russkiy, zaliv Petra Velikogo, Yaponskoye more)

Abstract

Purpose. The paper is aimed at studying the hydrological regime of the Novik Bay (Russky Island, Peter the Great Bay, Sea of Japan). Methods and Results. Regular ship and ice cover CTD observations (more 1000 water column profiling stations) carried out in the Novik and Amur bays in 2013–2018 were used. Weather conditions in the region under study were analyzed based on the data of the Vladivostok weather station archive (WMO_ID=31960). Quantitative estimates of the drift and gradient currents in the bay are represented. Conclusions. Seasonal changes in the thermohaline stratification of the Peter the Great Bay coastal waters are conditioned by the monsoon climate features. The Novik Bay hydrological regime is additionally affected by its isolation and shallowness, as well as by the Russky Island relief. Weak water dynamics in the bay is observed during the summer monsoon (April – August) that is a result of the south winds blocking by the hills. The autumn-winter monsoon (when the north winds dominate) induces the water surge to the bay that, in its turn, blocks its circulation. The winter Siberian cold anticyclone forms the ice cover in the bay, and just in such an ice-forming season the salinity increase in the bottom layer is observed. In the shallow southern part of the Novik Bay, the process of ice formation begins. The downwelling flow of salty heavy water directed to the north out of the bay along the bottom relief is compensated by the counter flow of fresh waters from the Amur Bay which inflow to the upper sub-ice layer. The freeze-up period is most favorable for water renewal. The efficiency of this process is additionally influenced by a heat flow from bottom sediments and by the ice conditions in the adjacent water areas of the Peter the Great Bay