Internal Tides and Ocean Mixing

TLDR

Observations reveal that ocean ridges and other seafloor topography transfer substantial tidal energy into internal tides, sourced from the Earth‑Moon system’s rotational energy. Garrett explains how internal waves with tidal periods propagate through the density‑stratified deep ocean and eventually break down into turbulence. The resulting turbulence mixes the ocean, affecting stratification, circulation, climate, and biological production.

Abstract

Recent satellite and in situ observations have shown that at ocean ridges and other seafloor topographic features, a substantial amount of energy is transferred from the main ocean tides into "internal tides." In his Perspective, Garrett explains how these internal waves with tidal periods propagate through the density-stratified deep ocean and eventually break down into turbulence. The resulting mixing affects ocean stratification and ocean circulation. It thus influences climate as well as biological production. The energy for the internal tides is derived from the rotational energy of the Earth-Moon system changes of the length of the day and the distance to the Moon.