A Study on Key Determinants in Enhancing Storm Surges Along the Coast: Interplay Between Tropical Cyclone Motion and Coastal Geometry

Abstract

AbstractGeneralizing the relationship between cyclonic features and storm surges remains challenging because previous studies have produced diverse results for different regions and historical events. We implemented Delft3D‐FM simulations and examined the synthetic effects of translation speed Vt and landfall angle α on maximum surge height (MSH) along an open coast and bay. By simulating idealized cases with varying Vt and α, we found that fast translation of a tropical cyclone (TC) magnified the MSH, with the most extreme MSH occurring when the landfall angle was almost perpendicular to the coastline. In addition, the simultaneous presence of smaller α and slower Vt conditions for a TC can trigger coastally trapped waves arriving ahead of its landfall. The impacts of the Proudman and Greenspan resonances contribute substantially to the MSH, depending on the conditions of the TCs and their topographies. We quantitatively assessed the effect of coastline geometry, and the results revealed that the morphological ratio influenced the MSH. Our findings suggest that the synthetic effects of cyclonic and topographic factors are critical for generating resonance and trapped waves that can modify main surges. The application of our findings from idealized cases to realistic cases based on historical TC indicates their applicability to storm surge risk assessment. Finally, we conducted a factor‐based diagnosis for the rapid evaluation of MSH, which can provide insightful references for future storm surge mitigation.