Observations of Boundary Mixing over the Continental Slope

Abstract

Observations of mixing over the continental slope using a towed body reveal a great lateral extent (several kilometers) of continuously turbulent fluid within a few hundred meters of the boundary at depth 1600 m. The largest turbulent dissipation rates were observed ove ra5k mhorizontal region near a slope critical to the M2 internal tide. Over a submarine landslide perpendicular to the continental slope, enhanced mixing extended at least 600 m above the boundary, increasing toward the bottom. The resulting vertical divergence of the heat flux near the bottom implies that fluid there must be replenished. Intermediate nepheloid layers detected optically contained fluid with u‐S properties distinct from their surroundings. It is suggested that intermediate nepheloid layers are interior signitures of the boundary layer detachment required by the near-bottom flux divergance.