The recent development of storm surge modeling in Taiwan

Storm surge is an important issue in Taiwan because our country is located at the typhoon prone area and surrounded by the Pacific Ocean and the Taiwan Strait. People live at coastal areas need to pay attention to the damages of storm surge, especially the inundation during typhoon's duration. Therefore, the accurate and highly efficient operational storm surge system is required to provide not only the information of water elevations but also potential inundation areas. The large computational domain should be adopted to cover the complete typhoon life-cycle, and the atmospheric model and tidal model are expected to be coupled inside. COMCOT-SS (COrnell Multi-grid Coupled Tsunami Model - Storm Surge) fulfils above-mentioned requirements and solves nonlinear shallow water equations with multi-scale wave propagations and inundation calculation. In this study, 2015 category-5 Typhoon Soulik is chosen for model validation, and the results are in a good agreement with observed data. Coastal inundation induced by Typhoon Soulik is also simulated to study the variation of storm tides and tides. By a series of strict validations and operational experiments, COMCOT storm surge operational system has been the official forecasting model at Central Weather Bureau, Taiwan since July, 2016, and has successfully predicted the storm surges induced by 2016 category-5 Typhoon Nepartak.