Influence of Relative Sea Surface Warming on Vertical Wind Shear Trend in the Western North Pacific Basin

Vertical wind shear (VWS) in large‐scale environmental flows plays a critical role in shaping tropical cyclone (TC) activity. Understanding how VWS responds to climate change is essential for assessing and projecting changes in TC activity. This study examines VWS trends over the western North Pacific and explores its relationship with the zonal pattern of SST warming pattern, using reanalysis datasets and historical simulations from Phase 6 of the Coupled Model Intercomparison Project (CMIP6). The reanalysis data for the period 1965–2023 reveal significant westerly trends in VWS over the region 10°–20° N, 120°–180° E, associated with relative warming of the western North Pacific SST compared to the eastern tropical Pacific. Whilst CMIP6 historical simulations exhibit substantial inter‐model spread, they consistently show that stronger relative warming in the western North Pacific corresponds to stronger westerly VWS trends. These findings highlight the importance of accurately simulating the zonal SST gradient to assess and project the impacts of climate change on TC activity in the WNP basin.