Spatial characteristics and prediction of tropical cyclone-induced storm surge along the Guangdong and Hong Kong Coast

Abstract

This study investigates the spatial characteristics and prediction of Tropical Cyclone (TC)-induced storm surges at 18 coastal sites along the Guangdong and Hong Kong coasts when TCs are within 800 km of the sites, using the TC best-track datasets and European Centre for Medium-Range Weather Forecasts datasets from 2009 to 2023. Innovatively, we developed a figure-based statistical model utilizing polar coordinates to determine TC positions relative to specific sites, with shadings denoting historical storm surge values at the site associated with TC intensity, position and size. The model for storm surges at the 18 sites induced by TCs was calibrated with data from 2009 to 2018 and validated with data from 2019 to 2022. Data from 2023 was used to test the model's predictive accuracy. Results show that TC intensity is a significant driver of storm surge, with higher-intensity TCs causing larger surges. Storm surges are influenced by TC azimuth and distance relative to the sites. TCs in the southeast and southwest quadrants, particularly within 600 km, generate more severe surges. Notably, TCs within 0–200 km of the sites, regardless of quadrant, pose the highest risk due to their high intensity around landfall. TC size and SLR also play crucial roles, with larger TCs and higher SLR values (computed using a 60-km radius) leading to larger surges. The figure-based statistical model effectively predicts TC-induced storm surges with minimal computational resources and provides a valuable tool for forecasting future storm surges, supporting disaster preparedness and mitigation efforts along the coast.