Species specific anthropogenic aerosol impacts on Northwest Pacif 2026 Chemo

Sea surface temperature (SST) in the Northwest Pacific exerts a first-order control on typhoon genesis, monsoon dynamics, and regional ocean – atmosphere feedbacks. Yet the extent to which anthropogenic aerosols, especially their distinct chemical species, modulate SST remains insufficiently understood, limiting our ability to attribute observed variability and to improve coupled model performance. Here, using high-resolution WRF-Chem simulations, we disentangle the species-dependent impacts of aerosols on SST through both direct radiative forcing and cloud-mediated indirect pathways. Accounting for aerosols reduces the regional SST bias by 13% and reveals a robust vertical cloud adjustment pattern characterized by enhanced low clouds and suppressed high clouds. Sulfate and organic carbon exert strong cooling effects, black carbon drives localized warming through atmospheric absorption, and ammonia substantially amplifies indirect cooling via cloud microphysical responses. These results highlight the crucial role of aerosol chemical composition in shaping regional SST patterns, with significant implications for predicting typhoon activity, monsoon variability, and ecosystem responses in the Northwest Pacific.