High-resolution hazard risk assessment of tropical cyclone based on parametric wind field models: a case study of Fuzhou City

Climate change and rapid socio-economic development have significantly increased the risk of tropical cyclone (TC) disasters in coastal areas, highlighting the urgent need for high-resolution hazard risk assessments. This study established a universal framework for high-resolution TC wind hazard assessment by integrating high-precision geographic information data and parametric wind field models, taking Fuzhou City as a case study. First, TC track data affecting the research area were extracted from the best-track dataset. For each track, a high-resolution wind field distribution was simulated by sequentially using classical gradient wind models, boundary layer wind field models, and gust models. Extreme value distribution methods were then applied to generate 100-meter grid-resolution maps of extreme wind speeds for typical return periods. Case analyses demonstrated that parametric wind field models could effectively capture the spatiotemporal evolution of wind speeds during tropical cyclone landfalls or transits, though simulated wind speeds slightly underestimated observational data. The hazard assessment results for typical return period wind speeds show that the distribution of extreme wind speeds in the Fuzhou area decreases gradually from the coast to inland. Specifically, high wind speed areas are mainly located along the eastern coast of Fuzhou, the southeastern low-altitude plains, Min River channel and its banks, and the western ridges and steep slopes, with maximum wind speeds for 50, 100, 200, and 500-year return periods reaching 40.6, 44.8, 48.9, and 53.9 m/s, respectively. The central urban area of Fuzhou, surrounded by mountains and hills and with dense urban construction, exhibits a uniform wind speed distribution with moderate-to-low hazard levels, while the western valley area shows the lowest hazard level due to the blocking effect of high mountains. This study not only provides a reference for the design wind parameters of engineering structures in coastal areas to resist typhoons but also guides to the formulation of refined disaster prevention and mitigation strategies.