An approach to modeling wind currents in Kerch Strait

Abstract

The Kerch Strait plays an important role in the for� mation of the oceanographic regime of the Black Sea and the Sea of Azov, which are connected by this strait. In the conditions of the modern climate changes and anthropogenic influence on the marine ecosystems, the strait is a natural transport link for these interac� tions. In addition, the characteristics of the ecosystem in Kerch Strait are subjected to significant variations, which influence the character of its economical use. Systematic investigation of currents in the Kerch Strait connecting the Sea of Azov and the Black Sea is principally important for understanding the physical nature of circulation variability and its influence on the regional climate. The water level regime in Kerch Strait is formed under the influence of two main causes: fluctuations of the sea level in the Black Sea and the Sea of Azov and direct wind forcing with account for the coastline form and bottom topography. Wind forcing has a double effect: on the one hand, it causes sea level variations at the ends of the strait and in the strait that results in the gradient currents and, on the other hand, it influences the water surface directly and causes the velocity vari� ations and sometimes variations in the direction of the currents due to the tangential wind stress. Wind plays the main role in the formation of currents in Kerch Strait. The wind flows over the entire basin and over the strait. The current field is also influenced by the difference in the sea level at the ends of the strait caused by the onshore and offshore wind currents and differences in the freshwater balance in the basins of the Black Sea and the Sea of Azov. DESCRIPTION OF THE MATHEMATICAL MODEL The coastline of Kerch Strait is very complex. It is indented by bays and spits, and the existence of Tuzla Island makes the calculation domain multiply con� nected. It is also important that the bottom topogra� phy of the strait is very uneven. The depths of the nav� igation part of the strait are 8–10 m and increase in its southern part to 19 m. At the same time, the depth of the coastal region in Tamanskii and Dinskii bays ranges between 0.5 and 4 m. Such a distribution of depths allows us to state that the bottom topography is