Abstract
In this study we develop a new parameterization for turbulent mixing in the ocean surface boundary layer (OSBL), including the effect of Langmuir turbulence. This new parameterization builds on a recent study (, hereafter ), which predicts the available energy for turbulent mixing against stable stratification driven by shear and convective turbulence. To investigate the role of Langmuir turbulence in the framework of , we utilize data from a suite of previously published large-eddy simulation (LES) experiments (, hereafter ) with and without Langmuir turbulence under different idealized forcing conditions. We find that the parameterization of is able to reproduce the mixing simulated by the LES in the non-Langmuir cases, but not the Langmuir cases. We therefore investigate the enhancement of the integrated vertical buoyancy flux within the entrainment layer in the presence of Langmuir turbulence using the LES data. An additional factor is introduced in the framework to capture the enhanced mixing due to Langmuir turbulence. This additional factor depends on the surface-layer averaged Langmuir number with a reduction in the presence of destabilizing surface buoyancy fluxes. It is demonstrated that including this factor within the OSBL turbulent mixing parameterization framework captures the simulated effect of Langmuir turbulence in the LES, which can be used for simulating the effect of Langmuir turbulence in climate simulations. This new parameterization is compared to the KPP-based Langmuir entrainment parameterization introduced by , and differences are explored in detail.
Current affiliation: NOAA Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey.
Current affiliation: Fluid Dynamics and Solid Mechanics, Los Alamos National Laboratory, Los Alamos, New Mexico.
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