Abstract Recent mooring observations have suggested that geostrophic currents flowing over large‐scale topography with wavenumbers outside of the radiating internal lee wave range can generate strong, upward‐radiating Near‐inertial Internal Waves (NIWs), but the generation dynamics are unclear. In this study, a two‐dimensional nonhydrostatic numerical model based on MITgcm is conducted to investigate the interaction between geostrophic currents and large‐scale deep seamounts, discerning the generation mechanism of NIWs and clarifying the influence of seamount height and summit width on the wave generation. The results suggest that weak depth‐independent inertial oscillations are first excited when the flows encounter seamounts. Radiating NIWs are subsequently generated at the summit edge of seamounts. Near the summit edge on the lee side of the seamount, the accelerated mean flow can further develop and enhance NIWs via the nonlinear interaction between the mean flow and NIWs. As the seamount height increases, larger mean flows and stronger nonlinearity occur at the summit edge of the seamounts, generating stronger NIWs. Compared to flat‐topped seamounts (i.e., the more width summit), the sharp‐topped feature (i.e., the conical seamount) can induce stronger mean flows and nonlinear interaction near the summit edge on the lee side of seamounts via the hydraulic control, resulting in the generation of stronger NIWs.
Wang et al. (Mon,) studied this question.