Development of An Unstructured Storm Surge-waves-tide Coupled Model And Its Application

Abstract:

An unstructured storm surge-waves-tide coupled model, which was coupled through the Model Coupling Toolkit (MCT), was developed based on the ADCIRC (Advanced Circulation model) ocean model and SWAN (Simulating Waves Nearshore) wave model. The developed coupled model has high resolution in the coast area and can be run efficiently. By comparing with the existing ADCIRC and SWAN coupled model, which was coupled directly not through the MCT, the newly developed one can increase the simulation efficiency by 26.4 percent, when the computational grid and coupling processes of the two coupled model were the same.

The coupled model was used to simulate the storm surge and waves during the process of typhoon “Usagi” which formed in the western Pacific on September 17, 2013 and made landfall at Shanwei in Guangdong province. Three numerical experiments were done in the simulation to study the effect of wave-current interaction on the storm surge and waves. Results show that the coupled model can simulate the storm surge and waves well when considering the wave induced radiation stress, the wave effect on the wind stress drag coefficient and the modulation of current and water level on the waves. During the process of typhoon “Usagi”，the effect of wave radiation stress can result in a maximum of 0.75m increase in the extreme storm surge, and the wave induced wind stress can cause a -0.82~0.49m change of the extreme storm surge near the coastal area.

This study is valuable to the study of hurricane storm surge disaster assessment and the development of the operational storm surge prediction technique.