Characteristics of Storm Surge-induced Water Level Increase and Empirical Forecasting in the Pearl River Estuary West Guangdong Sea Area

In this paper, Guanchong Station and Beijingang Station were selected as the representative tide stations in the Pearl River Estuary West Guangdong Sea Area, and 30 typhoons from 2000 to 2021 were selected to quantitatively analyze the correlation of the distance and included angle between the typhoon landing point and the tide station with the storm surge, which was verified by an example of the storm surge-induced water level increase forecast in 2022—2023. The results show that for typhoons landing at the junction of Xuwen County, Zhanjiang City, Maoming City, and Yangjiang City, the peak value of water level increase mainly occurs 1~8 h before landing, and for typhoons landing at Yangxi County, Yangjiang City and the Pearl River Estuary, it mostly occurs 0.2~15 h after landing. The included angle between the landing point and the tide station ranges from 225° to 270°, and the distance is within 100 km, resulting in the highest peak water level increase. When the included angle between the landing point and Guanchong Station ranges from 225° to 270° within 100 km, or when the included angle between the landing point and Beijingang Station ranges from 45° to 90°, the maximum peak water level increase rises by about 0.6 m at Guanchong Station and about 0.07 m at Beijingang Station for every 10 km reduction in distance. The typhoon landing at the junction of Maoming and Yangjiang cities, as well as near Zhuhai City, has experienced a peak increase of approximately 0.3 m in maximum water level at Guanchong Station and 0.2 m at Beijingang Station for every 10 hPa decrease in central air pressure. The research results can achieve rapid single station forecasting and provide an effective reference for empirical forecasting of storm surges in coastal estuaries.