Development And Application Of A Coupled Atmosphere-Ocean-Wave Model

Interaction between the atmosphere and the ocean is complex, especially during the tropical cyclone when feedbacks between the atmosphere and the ocean, the atmosphere and waves, the ocean and waves are strong and variable. It is essential to implement the interaction between the atmosphere, the ocean and waves in the numerical simulation. An online coupled modeling system which is comprised of the atmosphere Model WRF, the third- generation wave model SWAN and the unstructured grid Finite-Volume ocean model FVCOM is developed. The Model Coupling Toolkit(MCT) is employed to exchange data fields between these models. The modeling system was applied in the simulation of an ideal example with a tropical cyclone. The main contents and conclusions of this thesis are summarized as follows:1. Taking use of MCT, an online coupled modeling system including wind-wave-current interaction comprised of WRF, SWAN and FVCOM is developed. Interpolation of data fields between structured-grid model WRF and unstructured-grid models FVCOM/SWAN is accomplished. The coupling of this system is achieved by exchanging data fields between the models concurrently. Sea surface wind velocities are provided by WRF, the sea surface temperature, the water elevation and depth-averaged velocities are provided by FVCOM, the significant wave height, the wave length and the peak wave period are provided by SWAN.2. The concurrent wind-wave-current coupling model has been applied in the simulation of an idealized case with tropical cyclone. This numerical experiment has been set in different control cases in order to compare, such as none-coupling one, the atmosphere-wave coupling one and atmosphere-ocean coupling one. The change of wind fields, wave fields and current fields has been analyzed. Some other statistical parameters like10 m height wind velocity, sea surface pressure and friction velocity have also been discussed. Results indicated that the tropical cyclone can drive the sea surface temperature to decrease, and the decreasing SST will feedback to the tropical cyclone. For the wave, the increasing sea roughness will also weaken the wind speed.