Responses of typhoon-induced storm surge extremes to sea level rise in the south Yellow Sea

Global warming has led to rising sea levels, intensifying storm surges and increasing the risks of extreme sea levels, which pose heightened threats to low-lying coastal communities. The fan-shaped tidal ridges in the south Yellow Sea, where significant nonlinear interactions occur between storm surges and tides, make the Jiangsu coast particularly vulnerable to large fluctuations in water levels, potentially worsening flooding risk in the face of sea level rise (SLR). This study establishes a wind-tide-surge framework for simulating surges and analyzing surge extremes influenced by three typhoon types: landfalling, right-recurving and north-forwarding. The maximum storm surges corresponding to each typhoon type and their variations under SLR scenario exhibit discrepancies, but higher surges are almost always found in the Radial Sand Ridges, indicating amplification effects by typhoons transiting from the south. Both typhoon trajectories and intensities are important for generating surges, but the right-recurving typhoons are the most influential because of their generally close positions to the Hangzhou Bay. Under SLR scenario, the enhancement of tidal regimes outweighs surge increases, along with their nonlinear interplay, collectively decide similar patterns of extreme sea levels in this region, with the most substantial extremes especially in the central-southern Radial Sand Ridges.