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The present paper is focused on reproducing the extreme polar low observed over the Barents Sea in early January 1975, on the metocean hindcast data and on analyzing the upper sea layer response to the cyclone passage. Methods and Results. All the calculations are carried out based on the Marine and Atmospheric Research System for simulating hydrometeorological characteristics of the western seas in the Russian Arctic (the Barents, White, Pechora and Kara seas). The main components of this system are the regional non-hydrostatic model of atmospheric circulation WRF (spatial resolution is 15 km) and the physically complete three-dimensional σ-model of marine circulation INMOM (spatial resolution is 2.7 km). The atmospheric reanalysis data and the results of previous studies are used. The polar low produced a severe impact on the central and eastern parts of the Barents Sea, namely, being strongly influenced by the storm winds, the near-surface current velocities changed significantly. During a storm period in these parts of the Barents Sea, the drift component prevails over the tidal one. The tidal component prevails in the shallow southern part of the Barents Sea even during the most extreme storm period. It is shown that a polar low can lead to increase of the sea surface temperature in the Barents Sea by more than 1°С. Conclusion. The sea surface temperature positive anomaly is formed by the dynamic processes associated with vertical mixing, upwelling in the western and central parts of the Barents Sea, the Ekman drift and downwelling near the Novaya Zemlya coast. Contribution of the sea-atmosphere heat exchange to formation of the surface temperature positive anomalies is negligible. On the contrary, in the southern part of the Barents Sea and in the Pechora Sea, a significant surface temperature decrease (by almost 1.5°С) is observed during a polar low passing. This is a result of the sea upper layer cooling due to the heat transfer from the sea surface to the atmosphere.

Small river plumes are typical features at many coastal regions in the World Ocean. These water masses have relatively small areas and volumes; however, due to their energetic dynamics localized in a thin surface layer, they strongly affect coastal circulation, water quality, and ocean-atmosphere interaction. In this study, we investigate external factors, which govern synoptic and seasonal variability of small river plumes, and, therefore, affect land-ocean fluxes of fluvial water and biogeochemically important material. We use numerical modeling to simulate small river plumes at the northeastern part of the Black Sea. We describe the response time of small river plumes to changes in river discharge and wind forcing conditions, which determines variability of river plumes at different time scales. We reveal that the influence of river plumes on coastal processes depends not only on total annual river discharge volume, but also on temporal distribution of high-discharge and low-discharge periods. Seasonal and synoptic features of local atmospheric circulation could strongly modify the relation between river plume characteristics and river discharge rate. The results obtained in this study are important for better assessment of delivery and fate of river-borne suspended and dissolved matter, as well as floating litter in coastal areas.