Numerical Simulation of the Wind-Induced Current in the Caspian Sea

A three-dimensional primitive equation model has been developed to study wind-driven currents in the Caspian Sea (CS). The equations were solved in the spherical coordinate system with a vertical array of pressure-sigma using a finite difference Method on a staggered modified Arakawa c grid. Simulations showed that there is an anticyclonic eddy over the deep water of South Caspian Basin (SCB), which extended from surface to subsurface and persist throughout the year. The model successfully produced the coastal current along the eastern coast of the Middle Caspian Basin (MCB) with a prevailing southward component, resulting in upwelling on these coasts to compensate the surface drift. The results indicate that the bottom topography has a key role in steering currents and generated a divergence in the surface Ekman layer which balanced by convergence in the frictional bottom Ekman layer in deepest areas of the CS.