Sensitivity of Storm Surge to Typhoon Track, Intensity, Size, and Translation Speed in the East China Sea: A Case Study of Typhoon Winnie (1997)

Storm surge is a major coastal hazard in the East China Sea. A coupled tide–surge model forced by blended parametric typhoon and reanalysis winds was used to examine sensitivity to typhoon track, central pressure, radius of maximum wind (Rmax), and translation speed, with Typhoon Winnie (1997) as the baseline. The model was validated against observed total water levels, while surge residuals were not independently validated. Results show strong spatial variability and tidal-phase dependence. Track shifts mainly redistribute the alongshore surge response, whereas central pressure, Rmax, and translation speed primarily modify surge magnitude under the tested scenarios. A 3° southward track shift increased peak surge at Minjiangkou from 0.53 to 1.45 m; increasing Rmax by 20 km raised the Hangzhouwan peak from 0.84 to 1.19 m, and doubling translation speed raised it to 1.27 m. Process diagnostics further show that Hangzhou Bay is shallower than the open-coast reference sector and that 66.3% of evaluated grid cells exhibit positive pre-peak transport convergence, supporting bay-scale geometric amplification. These findings provide process-based guidance for scenario construction and coastal hazard assessment.