Climatic impacts of parameterized internal-wave driven mixing

Turbulent diapycnal mixing is a crucial driver of the thermohaline circulation and plays a key role in the transport and storage of heat and carbon dioxide. In the ocean interior, breaking internal waves generated by the interaction of tides and geostrophic flows with the topography, or by wind events at the ocean surface are the main driver of diapycnal mixing. Internal wave driven mixing is patchy in time and space and occurs on scales too small to be explicitly resolved in ocean climate models. Physically based parameterizations of internal-wave driven mixing are therefore needed for realistic simulation of the ocean and for estimating how mixing might change in a changing ocean.

Here, I will present parameterizations of internal-wave driven mixing for ocean models that have been developed as part of the US CLIVAR Climate Process Team on Internal-Wave Driven Mixing (http://www-pord.ucsd.edu/~jen/cpt/) and implemented in NOAA/GFDL's climate model ESM2G. Climate simulations of 1000 years are used to assess the sensitivity of the ocean state to these parameterizations. I will especially focus on the sensitivity of the thermohaline circulation, ocean ventilation, temperature field and of steric sea level to parameterizations of local and remote internal-tide dissipation and of lee-wave driven mixing.