Composite Extreme Wind-Wave Event: Asymmetric Forcing From Typhoon and Cold Air in a Temperate Semienclosed Sea

Abstract

With ongoing climate change and the observed poleward migration of typhoon tracks, the simultaneous occurrence of typhoons and cold air in temperate seas has emerged as a critical topic in oceanographic research. While previous studies have examined wave dynamics under individual typhoon or cold air forcing, the oceanic responses to their combined effects remain poorly understood. Here, we investigate the asymmetric forcing and relative contributions of these two extreme weather systems to wave characteristics and sea state variations in a semienclosed sea using a wind field decoupling approach. Our results demonstrate that the superposition of the two extreme wind fields may weaken wave energy due to wind offset and nonlinear wave-wave interactions, with the most pronounced changes in sea state occurring near the typhoon track. Spatial differences and clusterings in various sea areas are related to the cold air intensity and coming direction, typhoon translation direction, and the relative position to the typhoon center. This study advances our understanding of wave dynamics driven by the interaction of subtropical (typhoon) and subarctic (cold air) processes, with implications for improving sea state prediction in temperate semienclosed seas.