Simulation of the Evolution of Wave Fields Induced by a Moving Cyclone over the Northwest Shelf of the Black Sea

Abstract

The wave fields generated by cyclonic atmospheric disturbances in the region of the northwest shelf of the Black Sea are studied by using a σ-coordinate model. The problem is solved in the hydrostatic approximation with regard for nonlinearity and turbulent viscosity. To improve the space resolution of the model, we realize the procedure of embedded grids. It is shown that the action of a cyclone results in the formation of domains of pronounced surges whose shapes and location reflect the changes in the wind situation. The vertical structure of wave currents first depends only on the location of the atmospheric disturbance over the water area but, in the course time, begins to reflect specific features of the bottom topography.

Investigation of the fields of concentration of the suspension on the northwest shelf of the Black Sea in the case of roiling of the bottom sediments by a moving cyclone

“…The results of numerical integration of Eq. (5) with boundary conditions (8) and (11) carried out under the assumptions that the fields of horizontal velocity and concentration of the suspension are uniform and that the vertical advective transport is absent demonstrate that the correct distribution of turbidity in depth can be obtained for K H > w s max { D Δ σ } , where Δ σ is the distance between the neighboring σ-levels. In the numerical calculations, to satisfy the indicated condition, we set K H = 10 -4 m 2 / sec and w s = 10 -5 m / sec.…”

“…In the original equations (1), (2), (4), and (5) and in the boundary conditions (7), (8), (10), and (11), we pass from the Cartesian coordinate system to a σ-coordinate system by the formulas…”

“…Moreover, it is of interest to determine the locations of the regions of rise of the suspension, the directions of its transfer, and the vertical distribution of suspended substances in the case where the dynamics of waters is formed under the influence of a moving cyclone. In the present work, these investigations are carried out for the northwest shelf of the Black Sea on the basis of the numerical sigma-coordinate hydrodynamic model [8] adapted to the regional conditions. In specifying the erosion and sedimentation flows, we use the approximation which proved to be quite efficient for the simulation of turbidity in the estuaries [7,9].…”

Studying the influence of cyclonic activity on suspension distribution in the sea water of the northwestern Black Sea

“…The influence of atmospheric processes on water dynamics in this region can be decisive, since unsteady flow velocities that occur there under the effect of cyclonic formations can exceed 80 cm/s [1], while climatic flow velocities do not exceed 10-15 cm/s [3]. A nonlinear barotropic sigma-coordinate numerical model is used to calculate hydrodynamic fields [1]. Mathematically, the model is based on the ROM model [8], but in numerical realization to approximate advective terms, it uses the Superbee scheme [11].…”