Submesoscale features of coastal upwellings in the Black Sea: Observations and modeling

Abstract

Coastal upwellings significantly affect the thermohaline structure, gas exchange and the fluxes of nutrients in the upper layers. They are often characterized by complex spatial structure, which is related to impact of different factors – changes of bathymetry, impact of background currents, baroclinic instability and others. In this study, we use high-resolution NEMO numerical model-ling and satellite data to study in details several physical causes of the observed submesoscale features of the Black Sea coastal upwellings: . 1) the influence of capes on the separation of coastal upwelling from the coast and its further transformation into submesoscale eddies; 2) the influence of mesoscale eddies on the structure of coastal upwellings; 3) the role of river plumes and haline fronts in the transport of upwellings. Comparison of model and satellite data shows that the numerical calculations reasonably well reproduce the onset time, intensity and areas of upwellings. Further, we show that the discussed processes can significantly affect the intensity, evolution and propagation of coastal upwellings in the Black sea.