Storm Surge Induced by Tropical Storm Pabuk (2019) and Its Impact by Track Variation Scenarios on the Thailand Coast

Abstract Tropical Storm Pabuk, the most significant event in the past two decades, offered a unique opportunity to assess storm surge impact on the Gulf of Thailand coast. Employing the COMCOT-SURGE model with a two-layer nested-grid configuration, this study examined storm surges from offshore to nearshore driven by the ERA5 reanalysis winds and the 1980 Holland wind model. The spatial and temporal variations of storm surges due to Tropical Storm Pabuk were investigated. The ERA5 case indicated severe storm surges in Chumphon and Surat Thani and matched well with the measured surges in the timing and amplitude of peak surges. However, the HWM case showed the maximum storm surges shift southward, with more severe storm surges observed in Nakhon Si Thammarat, and poorly agreed with the observations. It is attributed to the environmental winds. Moreover, the effect of the radius of maximum winds was tested. This study focused on variations in storm tracks along the latitudinal axis and associated storm surges. Among the proposed track scenarios, the one landing between Chumphon and Surat Thani represented the most hazardous case to the Thailand coast, and Pabuk's track is the second one. Among all the proposed scenarios, Chumphon, Surat Thani, and Nakhon Si Thammarat face higher storm surge risks than other regions.