Numerical Simulation of Typhoon Waves in Ningbo Waters Based on the Holland Model

As a critical coastal hub port in China, Ningbo Zhoushan Port is significantly threatened by typhoon-induced waves with respect to wharf structural safety, navigational channel guarantee and port operational efficiency. Extreme wave conditions damage wharf facilities and exacerbate the risks of vessel berthing. Therefore, high-precision simulations of typhoon waves are urgently needed to provide scientific support for port disaster prevention and mitigation. In this study, the third-generation numerical wave model simulating waves nearshore(SWAN) was adopted to simulate typhoon waves induced by two typhoons affecting the Ningbo sea area: typhoon No. 2211 (Hinnamnor, 2022) and the landfalling typhoon No. 2212 (Muifa, 2022). European Centre for Medium-Range Weather Forecasts(ECMWF) reanalysis v5 (ERA5) wind fields were coupled with the Holland parametric wind model, and numerical simulations were performed for the Ningbo sea area using an unstructured grid. Particular attention was paid to the calibration and optimization of the typhoon influence range parameter in the Holland model. The simulated significant wave heights were compared with the measured data from the Zhujiajian buoy. The results demonstrate that after optimization, the correlation coefficient between the simulated and observed significant wave heights reaches 0.959 1, indicating that the model can accurately characterize the dynamic evolution of wave heights during the impacts of typhoons Hinnamnor and Muifa. Further analysis of the spatial distribution characteristics of wave heights during typhoon events reveals that the morphological features and overall distribution of typhoon waves are significantly modulated by the typhoon center position, nearshore topography and water depth conditions. The Zhoushan Archipelago exerts a certain protective effect against typhoon waves generated by both types of typhoons; nevertheless, typhoon waves still pose an obvious threat to navigation and berthing safety, with the impact of landfalling typhoons being more prominent.