Impact of typhoon translation speed on swell-dominated wave energy redistribution along Zhejiang Coast

This study investigates the impact of typhoon translation speed on wave spectral evolution and swell-dominated wave energy redistribution in the coastal waters of Zhejiang Province, China. Three historical typhoons with low, medium, and high translation speeds were selected as representative cases. The results show that translation speed affects the phase alignment between wave components; slow-translation typhoons advance swell spectral peaks towards wind/mixed waves. Reduced speed prolongs wave forcing but shrinks significant wave height (SWH) spatial coverage, while higher speeds amplify peak SWH and expand impact zones. During the active process, notable right-left asymmetry emerges, with SWH in the typhoon’s right-front quadrant reaching 2–3 times that in the left quadrant. This asymmetry drives southeastward-propagating swells, concentrating the major part of nearshore wave energy along Zhoushan’s southeastern coast. This study reveals the wave dynamic mechanisms and provides a theoretical reference for typhoon wave disaster forecasting in complex archipelago regions.