Semidiurnal internal wave global field

Estimates were made for semidiurnal internal wave generation over subsurface ridges based on Baines(Deep-Sea Research, 29, 307–338, 1982) linear model of internal wave generation. Flux was estimated from current measurements and numerical models of the global barotropic tidal field. Energy fluxes from the underwater ridges greatly exceed the fluxes from the continental slopes because the dominating part of tidal flow is directed parallel to the coast line. They account for about one-fourth of the total energy loss from the barotropic tides. The subsurface ridges, if normal to the tidal flow, form an obstacle that can cause the generation of large internal waves. The generated semidiurnal internal waves may be extreme when the depths of the ridge crest are comparatively small with respect to the surrounding depths. Energy fluxes from most subsurface ridges were estimated. The decay of the internal tide during propagation was estimated from measurements with buoy arrays located normal to the ridges. Measurements were made on clusters and arrays of moored buoys in more than 30 areas of the ocean. Combined calculations and measurements result in a map of the global internal wave energy distribution and their amplitudes. Extreme amplitudes are registered near the Mascaren ridge in the Indian Ocean and the Great Meteor bank in Atlantic.