A numerical study of storm surge behavior in and around Lingdingyang Bay, Pearl River Estuary, China

A numerical study based on FVCOM model was carried out to investigate the storm surge behavior induced by Typhoon Mangkhut in and around Lingdingyang Bay, Pearl River Estuary. Through elaborate calibration, the simulation results matched well with the measurements on the tidal-gauge stations. The validated Typhoon Mangkhut simulation was used as a case to study temporal–spatial behavior of the storm surge. Specifically, hourly spatial distribution of surge evolvement before the landfall of Typhoon Mangkhut and the time series of the surge from the twelve points in and around Lingdingyang Bay were analyzed. Beyond that, a series of artificial typhoons were designed through revising some parameters of the original typhoon including the landfall time, central pressure deficit, landfall location and moving direction, to study the influence caused by typhoon uncertainties. Results show that the influence of landfall time is dominated by the rule of tide–surge interaction, namely the lowest surge on the high tidal level and vice versa. The results also illustrate that the response of the surge to the same shift of the pressure deficit for a typhoon is uneven in space. The response of surge is more sensitive near shallow coastal regions than that in deep sea. Through investigating the surge in response to the track for the original typhoon, we find that a west shift of the track makes the ascending surge advanced and an east shift of the track makes the receding surge delayed in Lingdingyang Bay. A decrease of the angle between the coast and the direction of movement enlarges the maximum surge and an increase of the angle induces the opposite result. This study could improve our understanding about how uncertainties of a northwesterly moving typhoon would induce the storm surge response along the coastal regions such like Lingdingyang Bay, in Pearl River Estuary.