Evaluation of Wave-Dependent Surface Roughness Parameterization Using a Coupled Atmosphere-Wave Model

The coupling of waves to the atmosphere is an obvious and necessary step toward a unified approach in order to improve the description of the atmospheric boundary layer and the forecast of ocean waves. There have been a number of studies on the effect of surface waves on air-sea transfer process, especially at high winds over the sea such as typhoons and hurricanes. Although an air-sea coupling in tropical cyclones is useful for improving model intensity forecasts, the wave-dependent surface parameterization at the air-sea interface has a strong influence on tropical cyclone structure and intensity. In this study, several wave-dependent surface roughness parameterizations are evaluated, and sensitivity of tropical cyclone simulations to the parameterizations is examined using a coupled atmosphere-wave model. The sea surface roughness estimated by several parameterizations may lead to the significant difference on both wave fields and typhoon intensity. A change of drag coefficients due to the roughness parameterizations makes the change of typhoon intensity because of frictional convergence changes, which results in alteration of wind fields, and then wave fields. Further details will be presented in the conference.