Anthropogenic inorganic aerosols dominate precipitation suppression over the Tibetan Plateau: A WRF-Chem simulation for 2016

The Tibetan Plateau (TP), known as the “Asian Water Tower,” is essential for regional water security, yet its precipitation regime is strongly influenced by anthropogenic aerosols through multiple pathways. However, the roles of different aerosol components and their underlying mechanisms remain poorly understood. Here, we combine multi-source observations with numerical simulations to investigate the effects of anthropogenic aerosols on precipitation over the TP in 2016. The results show that anthropogenic aerosols generally suppress precipitation across the TP, reducing annual precipitation by approximately 12.1%, with the strongest effect during the summer monsoon (about 17.7%). The suppression is most pronounced over the southern and eastern TP and is stronger for large-scale than for convective precipitation. Inorganic aerosols are identified as the primary drivers of this reduction. By increasing cloud droplet number concentration and decreasing droplet radius, they inhibit cloud-to-precipitation conversion and increase cloud liquid water content. In addition, their strong scattering of solar radiation induces atmospheric cooling, enhances subsidence over the southern TP, and weakens moisture transport, further suppressing precipitation. In contrast, black carbon absorbs solar radiation, leading to atmospheric warming, enhanced upward motion, and increased moisture inflow over the southern TP, locally enhancing precipitation. These findings clarify the distinct and competing effects of anthropogenic aerosol components on TP precipitation, with important implications for water resource management under climate change.