Simulation of storm surge with wave-current coupled model on unstructured grids

Abstract

Typhoon-induced storm surge, waves, and coastal inundation in the western and southern coast of Korea region are simulated using fine mesh unstructured grid model FVCOM(an unstructured-grid Finite-Volume Coastal Ocean Model) coupled to a coastal wave model SWAN. The reanalysis 10-m wind and air pressure data are produced by WRF and a relatively simple analytical wind model are used on Typhoon wind. The wave-current couple procedure includes depth dependent wave radiation stress terms, Stokes drift, vertical transfer of wave-generated pressure transfer to the mean momentum equation, wave dissipation as a source term in the turbulence kinetic energy equation, and mean current advection and refraction of wave energy. We considered the role of wave induced forces on typhoon storm surge and the role of storm surge on the nearshore wave-field. Model results show that the extent of the simulated inundation region is increased when the effects of waves are included. Waves significantly affect the storm surge, accounting up to 25% of the total surge. This simulations show the importance of the inclusion of the wave effects for the hindcast of the water levels during the storm surge.