Black carbon aerosols impact snowfall over the Tibetan Plateau

Abstract

Snowfall is the primary form of cold-season precipitation over the Tibetan Plateau (TP), crucial for the maintenance of glaciers and snow cover, affecting regional climates and water resources availability. Through an integrative analysis of observations, numerical simulations, and statistical analyses, we found that the spatiotemporal distribution of snowfall across the TP is significantly influenced by black carbon (BC) aerosols from South Asia and the TP. BC affects the snowfall process through multiple mechanisms. Specifically, BC significantly raises atmospheric temperature over the TP, thereby reducing snowfall, particularly in the central TP during autumn, with reductions reaching approximately − 9 mm water equivalent month⁻¹. Moreover, BC enhances cold-season moisture transport from the Bay of Bengal, increasing moisture flux in the southeastern TP and thereby augmenting snowfall in that area by up to 5 mm water equivalent month⁻¹. This study elucidates the complex impact of BC on the spatial–temporal snowfall patterns across the TP and provides important insights into the sustainable development of water resources in the region amid ongoing climate change.