Distribution And Controlling Mechanism Of Tropical Cyclone Induced Ocean Surface Waves

The study of ocean surface waves under tropical cyclone (TC) wind forcing is of value both operationally for improving predicting precision of TC-induced ocean waves and improving the forecast of TC structure and intensity, and scientifically for understanding momentum flux and thermal flux at air-sea interface under high wind speed condition. However, the wind-wave interaction term in the current wave model doesn't apply to simulate ocean waves under high wind speed. And researches to date didn't investigate the impacts of TC wind fine structure on mean wave parameters and wave directional spectra. Therefore, ideal numerical experiment was designed to improve input source term of the WAVEWATCHâ…¢wave model using the newest drag coefficient observational result, and the simulated results are estimated combined with TC Bonnie (1998). The ideal experiment shows that the improved model reduces magnitude of significant wave height (SWH)but doesn't change its spatial characteristics. The impact on mean wavelength (MWL) is same as SWH. And it has little influence on the mean wave direction (MWD) and wave directional spectra. The TC Bonnie experiment shows that the simulation results using drag coefficient decreasing as wind speed increases under high wind speed is best identical with observation result.A series of ideal numerical experiments are designed to quantify the influence of TC translation speed (TCTS), TC intensity (TCI), the radius of maximum wind speed (RMW), inflow angle, asymmetric structure of TC wind (ATCW) and the swerve during TC's motion on TC-generated waves. The results show that the asymmetric spatial distribution is sensitive not only to the asymmetric structure of TC wind but also to TC translation speed, the radius of maximum wind speed, inflow angle and the swerve during TC's movement. The position of maximum SWH moves backward with the increase of inflow angle and RMW, while it moves forward with increase of ATCW and TCTS. These characteristics of TC wind also can affect other wave parameters, such as mean wavelength, mean wave direction, peak direction. The TC inflow angle is important factor for reproducing double- or multi-peak in wave simulation, and the TCTS, RMW, intensity, ATCW also play additional role in reproducing bimodal peak of wave spectra. The simulating results with 40 degree inflow angle is similar to that with SLOSH. Hence, 40 degree can be used as inflow angle when lack of the SLOSH inflow angle.