Global Analysis of Storm Surge Seasonality

We perform the first global analysis of storm surge seasonality using surge data from a global hydrodynamic model with full coverage of coastal areas, providing valuable insights for regions not represented in alternative observational data sources. We apply directional statistics based on the mixture model of the von Mises-Fisher distribution to identify surge seasons and their characteristics. Results reveal that nearly half of the global coastal stations, predominantly in tropical and subtropical regions, either lack a distinct surge season or experience heightened surge activity across multiple periods. Furthermore, the seasonality of storm surges follows a consistent large-scale spatial pattern tied to regional atmospheric variables. Spatial variability in the length of surge seasons is minimal in regions with bimodal surge seasons; however, the variability of surge peaks differs. Lastly, the seasonal distribution of storm surges differs regionally due to the underlying storm regime. These results provide valuable insights into the seasonality of storm surges on a global scale, which is useful for coastal risk management.