Generation of an internal tide by surface tide/eddy resonant interactions

Abstract

The interaction of surface tidal currents and baroclinic geostrophic eddies is considered to determine whether energy can be transferred to baroclinic tides by this process. Theoretical and numerical analyses reveals that when the surface tide is uniform in the horizontal, the interaction is identically zero, even under resonant conditions. The resonant interaction results in maximum internal wave excitation when the horizontal scale of the tide is comparable to that of the eddies. Thus, this process is not an efficient mechanism for internal wave excitation in the deep ocean where barotropic tides vary over much larger scales than the eddies, but it may provide an additional wave source at low latitudes and in coastal regions where tidal horizontal modulation by topography can be significant.