Wind Profile in the Wave Boundary Layer and Its Application in a Coupled Atmosphere-Wave Model

Current models cannot capture well the impacts of wind waves on the atmospheric boundary layer. Here, we proposed a new turbulence closure model to estimate the wind stress in the wave boundary layer from viscous stress, shear-induced turbulent stress, wind-sea induced stress, and swell-induced upward stress separately. The misalignment between the wind stress and wind is also considered in the model. Single-column simulations indicate that (a) the swell-induced upward momentum flux increases the surface wind and changes the wind direction, (b) the misalignment between the upward momentum flux and wind has a more significant impact on the wind profile than that from the downward momentum flux, and (c) the impact of swell-induced upward momentum flux decreases with atmospheric convection. The proposed closure scheme was implemented into an atmosphere-wave coupled model. A month-long simulation over the ocean off California shows that the surface wind can be altered up to 5% by ocean surface gravity waves.

Automated summary

This study proposed a new turbulence closure model to estimate the impacts of wind waves on the atmospheric boundary layer. The results from single-column simulations and a month-long simulation showed that the swell-induced upward momentum flux increased the surface wind, the misalignment of momentum flux had a more significant impact on the wind profile than the downward momentum flux, and the impact of swell-induced upward momentum flux decreased with atmospheric convection.