A Global View on Internal Tides

Abstract

This is a review paper on generation of internal tides in the global ocean based on literature data and publications of the author. Energy fluxes of semidiurnal internal tide generation over submarine ridges were estimated based on modeling and measurements on moorings in many regions of the ocean. Data from 4000 moorings during a period of 50 years are considered. Regions of intense generation of internal tides are indicated. They are related to several underwater oceanic ridges. Energy fluxes from submarine ridges greatly exceed those from the continental slopes because generally the currents of the barotropic tide are parallel to the coastline. If the barotropic tide currents are normal to the ridge, they generate strong internal tides. They account approximately for one fourth of the energy losses of the barotropic tide. Decay of internal tide during propagation was estimated based on the data from lines of moorings located normal to the ridges. Model simulations and moored measurements result in a global map of semidiurnal internal tide amplitudes