Implementation of a Mesh Movement Scheme in a Multiply Nested Ocean Model and Its Application to Air–Sea Interaction Studies

A mesh movement scheme is implemented in a multiply nested primitive equation ocean model. Mesh movement can be specified or determined in the course of the model run so as to follow an evolving oceanic feature, such as a wave front or propagating eddy, or atmospheric forcing, such as a tropical cyclone. Mass, heat, and momentum are conserved during the movement. The mesh movement scheme is tested in idealized and realistic configurations of the model. The idealized tests include simulations in which the moving meshes follow a propagating equatorial Kelvin wave, a dipole, or move across an existing mesoscale eddy. The tests demonstrate that the solutions in the fine-mesh region of the nested meshes reproduce well the equivalent solutions from uniform fine-mesh models. The model is applied for simulations of the ocean response to tropical cyclones, in which the moving meshes maintain high resolution near the cyclone center. The solution in the inner meshes reproduces very well the uniform fine-mesh simulation, in particular the sea surface temperature. It demonstrates that the moving meshes do not degrade the solution, even with the application of strong winds and the generation of energetic surface currents and near-inertial gravity waves. The mesh movement scheme is also successfully applied for a real-case simulation of the ocean response to Typhoon Roy (1988) in the western North Pacific. For this experiment, the model is initialized using the fields from a general circulation model (GCM) multiyear spinup integration of the large-scale circulation in the tropical Pacific Ocean. The nested-mesh solution shows no difficulty simulating the interaction of the storm-induced currents with the existing background circulation.