On the nature of internal wave spectra near a continental slope

Amongst the most energetic motions in the deep ocean are internal waves supported by stable vertical stratification in density. Previously, these waves were considered freely propagating as described by a smooth continuum internal wave band (IWB) frequency spectrum. We studied details of the IWB using yearlong current observations from the Bay of Biscay. Instead of observing continuum IWB spectra near a continental slope, we show that (at least) the first half-decade of the IWB is dominated by motions at localized frequencies determined by strong non-linear interactions between waves at the fundamental semidiurnal tidal and atmospherically induced inertial frequencies.