Tide–Surge–Wave Interaction in the Pearl River Estuary during Super Typhoon Saola (2023)

Storm surge and storm waves are significant marine dynamic disasters that affect coastal areas globally. Interactions among tides, surges, and waves are complex and nonlinear, particularly in shallow coastal regions and estuaries. This study investigated the historical Super Typhoon Saola (2023) through hindcasting and analyzed tide–surge–wave interactions (TSWIs). To achieve this objective, six numerical experiments were conducted using the advanced circulation model (ADCIRC)  and the coupled ADCIRC + SWAN model. These experiments aimed to isolate the contributions of astronomical tides, storm surges, waves, and their nonlinear interactions to variations in water levels and significant wave heights (SWHs). Experimental results indicated that the nonlinear effects of TSWIs decreased from the outer edge to the head of Lingding Bay during Super Typhoon Saola. Furthermore, the contribution of wave setup to the total water elevation was found to be relatively minor. Current variations had a significantly greater influence on SWHs in Lingding Bay than water level variations. Moreover, tidal forces could substantially modulate SWHs through TSWI mechanisms. Notably, neglecting tidal effects resulted in a three-orders-of-magnitude reduction in the bottom stress terms, attributed to tidal current velocity and tidal level. This study underscored the critical importance of incorporating TSWIs into simulations related to typhoon-induced storm surges and storm waves. These factors are essential for mitigating typhoon-related disasters and designing criteria pertinent to societal infrastructure and coastal engineering.