Spatiotemporal Responses of Sea Level and Wave Height under Multi-Source Wind-Field Forcing: A Case Study of Typhoon In-fa

Typhoon-induced sea-level (water-level) variations and large waves constitute major coastal marine hazards, whose evolution is strongly governed by wind-field forcing. An accurate understanding of how wind-field uncertainty affects water-level and wave-height responses is essential for improving the reliability of numerical simulations of extreme events and for enhancing coastal disaster risk assessment. However, most existing studies rely on a single wind-field dataset and exhibit notable limitations: reanalysis wind fields tend to underestimate intensity within the typhoon inner-core region; parameterized vortex wind fields have difficulty accurately representing the background wind field and the asymmetric structure of typhoons; and studies on blended wind fields remain insufficient in elucidating the core mechanisms by which wind-field fusion drives variations in water level and wave height.Accordingly, this study takes Typhoon In-fa as a case study. Based on a wave–current coupled model, five comparative experiments were designed using different wind fields, including reanalysis, numerical simulation, parameterized, and two types of blended wind fields. Observational data of tide level, wind speed, and wave height were used for validation. Spatial clustering, correlation analysis, and Empirical Orthogonal Function (EOF) analysis were jointly applied to comprehensively investigate the spatiotemporal response characteristics of water level and wave height.The results demonstrate that the blended wind fields enhance the inner-core wind-speed gradient while maintaining a realistic background wind field. Variations in the blended wind fields exert a pronounced influence on wave height, whereas their impact on water level is manifested primarily in significantly increased nearshore water-level setup and in overall differences in spatial distribution. These differences are predominantly controlled by the lower-order EOF modes.