The recent history of our understanding of low-mode internal tides in the ocean

Abstract

The past decade has seen a renaissance in the interest in oceanic internal tides and their role in mixing the abyssal ocean. One of the sparks of this renaissance was the discovery of the remarkable coherence of low-mode internal tides using an ocean acoustic tomography array deployed in the central North Pacific Ocean in 1987. The result was subsequently confirmed by satellite altimetry. This talk will review these results and related results from the 1991 Acoustic Mid-Ocean Dynamics Experiment (AMODE) in the North Atlantic and the 2001 Hawaiian Ocean Mixing Experiment (HOME) around the Hawaiian Ridge. Internal tides are generated by tidal forces hence they are a means by which the tides dissipate energy. With wavelengths of 150-km, low-mode semidiurnal internal tides appear to propagate 1000’s of kilometers across ocean basins while retaining considerable coherence.