The generation of internal tides at the Hawaiian Ridge

Abstract

Previous analyses of altimeter and acoustic data indicate that the Hawaiian Ridge is a significant generation site for semidiurnal (M 2 period) internal waves owing to tidal flow over topography. Such waves likely play an important role connecting the dissipation of tidal energy to ocean mixing. Here a primitive equation numerical model with realistic stratification, bathymetry, and tidal forcing is used to simulate the generation of these waves in a manner consistent with altimeter sea surface observations. The highest amplitude waves originate at three generation sites located at both the island and seamount portions of the chain. These sites have in common both enhanced flows across ridge‐shaped topography and maxima in model calculated body force which couples barotropic and baroclinic motions. The model vertical structure suggests the presence of multiple dynamical modes within 100 km of the ridge and not just the lowest modes that have been detected at the sea surface.