Internal tide breaking at topography

Breaking internal waves drive much of the mixing in the stably stratified ocean interior. Tidal flow over topography is one source for generation of these internal waves. Numerical simulations reveal several mechanisms for breaking of internal tides, including transient hydraulic jumps, nonlinear wave-wave interactions and wave reflection from sloping and shoaling topography. In all three scenarios, the steepness of the topography has a strong influence on the wave-breaking behavior. Quantification of the net loss of energy from the internal waves to small-scale motion and dissipation, and the dependence of that dissipation on topographic parameters, stratification and flow amplitude provides guidance for parameterizations of internal-tide driven mixing suitable for climate models. Coupled climate model simulations demonstrate the impact of the distribution of internal-wave driven mixing on the large-scale circulation and climate.