Effect of Wave Radiation Stress in Storm Surge-Induced Inundation: A Case Study for the East Coast of India

Tropical cyclone-induced coastal inundation is a potential hazard for the east coast of India. In the present study, two case studies are presented to examine the significance and importance of wave radiation stress in storm surge modeling during two extreme weather events associated with the Phailin and Hudhud cyclones. Model computations were performed using the advanced circulation (ADCIRC) model and the coupled ADCIRC + SWAN (Simulating Waves Nearshore) model for these two events. Meteorological and astronomical forcing were used to simulate the hydrodynamic fields using the ADCIRC model run in a stand-alone mode, whereas the coupled ADCIRC + SWAN model also incorporated the wave radiation stress attributed from wave breaking effects. Cyclonic wind fields were generated using the revised Holland model. Results clearly indicate an increase in the peak surge of almost 20–30% by incorporating the wave radiation stress and resulting inundation scenario in the coupled model simulation. The validation exercise showed that the coupled ADCIRC + SWAN model performed better than the ADCIRC model in stand-alone mode. Key findings from the study indicate the importance of wave-induced setup due to radiation stress gradients and also the role of the coupled model in accurately simulating storm surge and associated coastal inundation, especially along flat-bottom topography.