Generation and movement of two interacting tropical cyclones in a coupled atmosphere-ocean model with nested movable grids

Studied are the interaction of two developing tropical cyclones (TC) and the coupling between the ocean and a TC. The work is based on a coupled atmosphere-ocean model put forward in [4]. The model is formed by coupling an eight-level TC model in sigma coordinates with a three-layer nonlinear oceanic model. The model incorporates the parametrization of the boundary layer by a method resembling that of Deardorf, and also the parametrization of the vertical and horizontal turbulent mixing. Initial conditions for modeling a developing TC were set same as in [4], with the maximum tangential velocity at the 120-km radius. Numerical experiments have been performed with a constant and variable Coriolis parameters, with and without incorporation of the ocean model. In different experiments, two identical axisymmetric vortices were set at different distances. During integration both vortices develop to become the TCs with the structures closely resembling those of actual TCs. It is shown that the development and motion of two TCs with and without incorporation of the oceanic model differ greatly. Studied are the fields of pressure, relative vortex, vertical motions, and sea surface temperatures.