Numerical investigation of interaction between anticyclonic eddy and semidiurnal internal tide in the northeastern South China Sea

Abstract. We investigate interaction between an anticyclonic eddy (AE) and semidiurnal internal tide (SIT) on the continental slope of the northeastern South China Sea (SCS), using a high spatiotemporal resolution numerical model. Two key findings are as follows. First, the AE promotes energy conversion from low-mode to higher-mode SIT; additionally, production terms indicate that the energy is also transferred from the SIT field to the eddy field at an average rate of -3.0 mW m^-2. Second, the AE can modify the spatial distribution of tidal-induced dissipation by both refracting and reflecting low-mode SIT. The phase and group velocities of the SIT are significantly influenced by the eddy field, resulting in a shift of the internal tidal rays to the north or south. These findings deepen our understanding of complex interactions between AE and SIT and of their impacts on energy conversion, wave propagation, and coastal processes.