SEMIDIURNAL INTERNAL WAVE GLOBAL FIELD

Estimates were made for semidiurnal internal wave generation over subs urface ridges based on BAINES (Deep-Sea Research, 29, 307-338, 1982) l inear model of internal wave generation. Flux was estimated from curre nt measurements and numerical models of the global barotropic tidal fi eld. Energy fluxes from the underwater ridges greatly exceed the fluxe s from the continental slopes because the dominating part of tidal flo w is directed parallel to the coast line. They account for about one-f ourth of the total energy loss from the barotropic tides. The subsurfa ce ridges, if normal to the tidal flow, form an obstacle that can caus e the generation of large internal waves. The generated semidiurnal in ternal waves may be extreme when the depths of the ridge crests are co mparatively small with respect to the surrounding depths. Energy fluxe s from most subsurface ridges were estimated. The decay of the interna l tide during propagation was estimated from measurements with buoy ar rays located normal to the ridges. Measurements were made on clusters and arrays of moored buoys in more than 30 areas of the ocean. Combine d 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.