Where large deep-ocean waves break

Abstract

Underwater topography like seamounts causes the breaking of large "internal waves" with associated turbulent mixing strongly affecting the redistribution of sediment. Here ocean turbulence is characterized and quantified in the lowest 100 m of the water column at three nearby sites above the slope of a deep-ocean seamount. Moored high-resolution temperature sensors show very different turbulence generation mechanisms over 3 and 5 km horizontal separation distances. At the steepest slope, turbulence was 100 times more energetic than at the shallowest slope where turbulence was still 10 times more energetic than found in the open ocean, away from topography. The turbulence on this extensive slope is caused by slope steepness and nonlinear wave evolution, but not by bottom-friction, "critical" internal tide reflection or lee wave generation.