Numerical Study Of Wave Breaking And Its Application In Coupled Modeling System

Based on the history studies of wave breaking and whitecap coverage, the paper summarizes the statistical wave breaking model and whitecap parameterizations, and discusses their pro and con. An improved model is derived by combining satellite-based parameterization and the wave breaking model. The appropriate constants for the general wave state are obtained by considering the breaking condition of the wave slope and fitting with the satellite-based parameterization. Comparing with satellite-based data and the original model’s results, the improved model’s results are consistent with satellite-based data and previous studies. The global seasonal distributions of whitecap coverage are presented and analyzed.A coupled modeling system COAWST is applied to study the atmosphere and ocean dynamics during Tropical Storm Nock-ten. Different atmospheric physical parameterizations in WRF model are investigated through ten groups of numerical experiments. By comparing results of atmosphere, ocean wave and current features with observations, we find that the storm track and intensity are sensitive to Kain-Fritsch cumulus scheme, Goddard shortwave radiation scheme and RRTM longwave radiation scheme, which may lead to much larger wind intensity, significant wave height, current intensity, as well as lower SST and sea surface pressure. By analyzing modeled data with observations in terms of fitting coefficient, root mean square error, correlation coefficient and model performance, the recommended atmospheric physical parameterization in this coupled system have been obtained.The connections between wave breaking and air-sea flux are established. Based on spray generation mechanism and breaking dynamic mechanism, water vapor flux due to wave breaking can be computed. Wave breaking model is applied to coupled modeling system so that the system can consider the air-sea flux due to wave breaking. By comparing simulated results of experiments based on spray generation mechanism and breaking dynamic mechanism with original model results, it shows that water vapor flux and latent flux of experiments considering wave breaking increase obviously, and more approximate to observations.