Ocean surface gravity waves, especially the resulting Langmuir turbulence (LT), affect the ocean surface vertical mixing, yet are missing in most of the global climate models (GCM). The lack of explicit representation of the effects of LT in GCMs may contribute to persistent biases in the simulated ocean mixed layer depth (MLD), air-sea heat and momentum fluxes, temperature distribution and tracer concentrations in the upper ocean.
To assess the effects of LT on global climate, large eddy simulations (LES) of the ocean surface boundary layer, which are able to simulate some of the key features of LT, are conducted. Parameterizations of LT in the K-Profile Parameterization are developed based on LES results, and then implemented and tested in the NCAR earth system model, CESM. It is found that accounting for the effects of LT in CESM significantly reduces the shallow MLD biases in the Southern Ocean, and improves the simulated intermediate water ventilation and ocean subsurface temperature.