Energy and Momentum of a Density-Driven Overflow in the Samoan Passage

Abstract The energy and momentum balance of an abyssal overflow across a major sill in the Samoan Passage is estimated from two highly resolved towed sections, set 16 months apart, results two-dimensional numerical simulation. Driven by density anomaly sill, flow relatively steady. system gains divergence horizontal pressure work flux available potential . Approximately half these are transferred into kinetic while other lost to turbulent dissipation, bottom drag, vertical work. Small-scale internal waves emanating downstream within layer radiate upward but dissipate most their dense at its upper interface. strongly sheared stratified interface acts as critical inhibiting any appreciable radiation via topographically generated lee waves. Form drag , drop consistent with dissipation wave fluxes. topographic removes mean flow, slowing it down feeding countercurrent aloft. processes discussed this study combine convert about one-third released cross-sill difference mixing observed modeled sustains gradients shear stratification, thereby maintaining efficient route for water mass transformation sill.