## 3 Results and Discussion
Specifically, we integrated a parameterization model with a background wind field to capture the mobile wind speed during the typhoon's movement and the background wind speed during the typhoon impact phase, respectively. Figure 7: Comparison between simulation and measured data of Sijiao station (**a**) ERA5 model (**b**) Fujita\(-\)Takahashi model. Based on the aforementioned ERA5 data and Fujita-Takahashi models, we selected the prelandfall period for the Fujita-Takahashi model's typhoon field and the postlandfall period for the ERA5 data wind field to simulate the storm surge water level. This approach allowed us to capture the dynamic interactions between the wind fields during different phases of the typhoon event. By combining these datasets, we aimed to enhance the accuracy and reliability of our storm surge simulations and generate valuable insights into the behavior of storm surges in the study area. To evaluate the effectiveness of our approach, we applied it to analyze the extreme water level increase due to Typhoon In-fa (2021) in the Zhoushan Sea area. Our methodology provides a comprehensive framework for comprehending the intricate dynamics of typhoon storm surges, and our results offer valuable insights into the potential impacts of these surges on coastal and estuarine regions. As illustrated in Figure 8, we selected the time points of high tide and low tide at the Daishan hydrological station (122\({}^{\circ}\)11.894\({}^{\prime}\) E, 30\({}^{\circ}\)14.64\({}^{\prime}\) N) as the calculation time for the storm surge and flow field. As the numerical model is capable of computing water levels across the entire calculation area, we analyzed the storm surge water level and its spatiotemporal variation during the event. Figures 9-14 present the spatiotemporal distribution of water level variations and storm surges during the occurrence of Typhoon In-fa (2021) in the calculation area. These visual representations offer valuable insights into the dynamic behavior of water levels and storm surges in the East China Sea. By systematically analyzing and summarizing the observed characteristics, our study establishes a robust scientific foundation for effective disaster prevention and mitigation strategies in coastal regions. Notably, the direction of the arrows in the figures indicates the prevailing water flow direction, while the arrow size corresponds to the magnitude of the flow velocity. Figure 10: Typhoon storm surge at 5:00 a.m. on 25 July (low tide). Figure 9: Typhoon storm surge in the 22:00 p.m. of 24 July (high tide). Figure 4:0 Typhoon storm surge at 11:00 a.m. on 25 July (high tide). Figure 4:1 Typhoon storm surge at 16:00 p.m. on 25 July (low tide). As shown in Figure 9, at the high tide of Daishan station at 22:00 p.m. on 24 July, the Yellow Sea and the East China Sea suffered the influence of the typhoon globally, and the extreme water level increase was within the range of 0-5 m. The extreme water level in the middle of the sea is 0.000 p.m. on 24 July, the Yellow Sea and the East China Sea suffered the influence of the typhoon globally, and the extreme water level increase was within the range of 0-5 m. The extreme water level in the middle of the sea is 0.000 p.m. on 25 July,  
the nearshore was greater than that in the open sea area, and the increase in water level in the open sea area was relatively small. The closer it was to Hangzhou Bay and the Yangtze River Estuary, the greater the extreme water level, among which the water level in the southern coastal area of Jiangsu rose by more than 4 m with a flow direction of SE. There was no significant rise in the water level in the central and northern coastal areas where the flow direction was S. The water level rise in Yangtze River Estuary, Zhoushan Islands, and Quanzhou in Fujian Province increased significantly by more than 4 m. The flow direction of the Yangtze River Estuary and Zhoushan Islands was E, while that of Quanzhou, Fujian, was N. This spatial variation can be attributed to the complex topographic conditions near the bay.