Spatiotemporal features of storm surges in the Zhoushan Archipelago from 2001 to 2020

Storm surges pose a critical coastal hazard, necessitating accurate modelling and understanding of their behavior. In this study, the Coastal and Regional Ocean Community model has been used to investigate spatiotemporal features of storm surges in the Zhoushan Archipelago. Based on simulations over 20 typhoon seasons (2001–2020), we find that islands closer to the mainland generally exhibit higher surge levels than remote offshore islands, suggesting that islands are subjected to varying degree of risk during a storm surge event. However, the specific distribution of storm surges depends on typhoon trajectories. Offshore-deviating typhoons lead to a general eastward diminution of surges, while typhoons that make landfall south of Zhoushan result in maximum surge heights along the southwestern islands’ coasts. In terms of temporal variation, storm surge integrated intensity exhibits a slight increasing trend, likely influenced by the decreasing distance of typhoon maximum intensity from Zhoushan. Furthermore, the integrated intensity of storm surge correlates positively with El Niño and La Niña events, particularly in regions characterized by intense storm surges. These findings provide valuable reference for the development of risk prevention and mitigation strategies in Zhoushan and other island cities.