Seasonal variability of oceanological conditions in the northern part of the Tatar Strait

Abstract

An average long-term distribution of temperature and salinity is analyzed for different months (May-November) computed on the basis of materials accumulated at standard oceanological sections of the northern part of the Tatar Strait. The main attention is paid to the section Korsakov Cape-Cape Syurkum crossing the water area under study practically in the middle. In early spring, the cold waters with salinity of more than 33‰ are registered at the section Korsakov Cape-Cape Syurkum. The waters with smaller salinity are revealed only in late spring, in June. In the same period, the intensification of cold intermediate layer occurs, first of all, in the western part of the section. The waters in the surface layer near the Sakhalin coast are warmed more than at the continental shelf. During the summer, this difference gradually decreases and the surface layer temperature becomes even in September. On the contrary, the spatial salinity gradients increase. In the fall, under the influence of northern and northwestern winds being typical of this period, the upwelling is formed near the Sakhalin coast and the cold dense waters emerge in the narrow coastal strip. The direction of alongshore flow changes from northern to the southern one. At the section Korsakov Cape-Cape Syurkum in November, the influence of small-salinity waters associated with the Amur River runoff is significantly revealed.

Ocean Dynamics and Methane Plume Activity in Tatar Strait, Far Eastern Federal District, Russia as Revealed by Seawater Chemistry, Hydroacoustics, and Noble Gas Isotopes

“…With an ice-free area established in our study area in February, it is not surprising that the shallow waters observed in June were much warmer than other years. In contrast, during 2019, following high Fall monsoonal discharge, the western margin is in large part open to southward circulation of the Primorye Current, consistent with the anticorrelation between Amur River Discharge and ice extent in the Okhotsk Sea (Ogi et al, 2001;Ogi and Tachibana, 2006) yet impeding the northward migration of warm saline Tsushima Current waters to the east as described by Shevchenko et al, 2011, resulting in ice cover across most of our study area and along the coast of Sakhalin Island.…”

“…If we compare Fall monsoonal discharge, both the mean and variability have increased from 33,200 ± 7,240 m 3 /s from 1990-1999 to 52,990 ± 21,540 m 3 /s, up by 37%. In general, we do not see a decreasing trend over time which would be attributable to increased water consumption through human activities as proposed by Shevchenko et al (2011) and if water usage is increasing, it is more than offset by other factors which increase discharge. As far as possible changes in discharge related to intense weather activities, the most extreme seasonal discharge during this period (Fall, 2013: 97,300 m 3 /s) is more than double that of the most extreme from 1990(Fall, 1994,700 m 3 /s).…”

“…Annual fluctuations in circulation appear to be intimately associated with the rate at which the Amur River discharges into the Okhotsk Sea across from the northernmost part of Sakhalin Island, and then spills over into Tatar Strait, thus influencing the northward migration of the Tsushima Current, and impacting both the thermohaline structure and circulation of water in the strait (Andreev, 2018;Ponomarev et al, 2018). As the Amur River is one of the largest rivers in East Asia, it has been hypothesized that increased water usage by humans as it courses through Mongolia, China, and Russia might lead to unintended changes in the thermohaline structure of Tatar Strait (Shevchenko et al, 2011). To assess the degree to which riverine discharge may have varied over time, we looked hydrological data provided by the Russian Federal Water Resources agency for Brodgoroskoye, located at the mouth of the Amur River (Figure 10, Supplementary Table S2).…”

Hydrological and Hydrochemical Water Structure in the Upwelling Zone Off the Southwestern Coast of Sakhalin Island

“…OF SAKHALIN ISLAND G. V. Shevchenko Based on the spatial distributions of sea surface temperature according to satellite observations and observational data on standard oceanographic sections of the southwestern shelf of the Sakhalin Island in summer (August) and autumn (November) shows the existence of seasonal upwelling, which is formed under the influence of northerly and northwesterly winds, typical of the winter monsoon. In this area, it manifests to a lesser extent than in the northern part of the Tatar Strait (Shevchenko et al, 2011) due to the features of the bottom topography (short deep shelf) and the large thickness of the upper heated layer, but quite clearly. At the same time, deep water rises, rich in biogenic elements and mineral phosphorus, which is important for the development of young growth of kelp.…”