ИСТИНА

Based on the long-term measurements and the hydrological survey, the first baroclinic Rossby radius of deformation (R 1 ) and the phase speed of the first mode of the coastal-trapped internal waves (с 1 ) are estimated in the Black Sea. To assess both variables on the continental shelf, the boundary value problem for the vertical structure of the vertical velocity is numerically solved at the given specified profile of buoyancy frequency. Long-term mean temperature and salinity of the Black Sea were collected by the Marine Hydrophysical Institute of RAS. The data on the northern shelf were collected during the hydrological survey on November 2017. We established that maximal values of R 1 and с1 vary from 17.5 to 18 km and from 1.7 to 1.8 m/s in the south-eastern part of the Black Sea, respectively. Minimal values of R1 (с1), amounting to less 15 km (1.1 – 1.5 m/s), were obtained in the northern and the central part of the Black Sea. Seasonal variability of R 1 and с 1 is characterized by their minimal values in winter and maximal values in summer and the difference between of them reaches 20 percent. On the south-eastern and southwestern shelfs of the Black Sea, there is a pronounced seasonally variability for both variables and the difference between their summer and winter values reaches 60 percent. At the numerical simulations of the pollution in the coastal zones of the Black Sea, it is necessary to allow for the influence of nonlinear internal waves. According to the obtained estimates of R1, the model grid resolution of 2 to 2.5 km should be used for the eddy-permitting numerical simulation of circulation in the Black Sea.