Enhanced atmospheric wave boundary layer model for evaluation of wind stress over waters of finite depth

It is known that the wind stress coefficient on sea surface is a key parameter in modeling ocean waves and depends on the wave condition at the same time, while an ocean wave condition is affected not only by the wind speed over the sea surface but also on the water depth in general. Investigating the effect of water depth on wind stress coefficient is thus of great importance for an accurate wave modeling in shallow waters. In this study, the atmospheric wave boundary layer model is enhanced by considering the effects of water depth on the wind wave spectrum and on the sea spray generation law so that the wind stress can be obtained under more general conditions. In particular, the high-frequency wave spectrum tail is improved by considering the effect of triad wave interaction in shallow waters. A sea spray generation law is developed by including dissipations due to both whitecaps and depth-induced breaking. Numerical results on the wind stress coefficient at different water depth can thus be obtained in good agreement with field observations. A simple formula is also proposed and is applied to modeling hurricane-induced waves on Lake Michigan. The computational results on significant wave heights show that the newly developed method for evaluating wind stress coefficient improves the performance of wave models in finite water depth.

Automated summary

It is important to investigate the effect of water depth on wind stress coefficient for accurate wave modeling in shallow waters. By enhancing the atmospheric wave boundary layer model with considerations on water depth, the newly developed method improves the performance of wave models in finite water depth.