Black carbon (BC), a major light-absorbing aerosol emitted from South Asian biomass burning, can be efficiently transported to the Tibetan Plateau (TP), substantially accelerating snowmelt. However, the relative contributions of different biomass burning sources and their future impacts on TP snowpack remain poorly quantified. Using the Community Integrated Earth System Model (CIESM), this study conducted a suite of sensitivity experiments to systematically quantify the impacts of BC emissions from South Asian biomass burning on snow cover fraction (SCF) and snow depth (SD) over the TP, and assessed the synergistic effects of sulfur dioxide (SOS) through aerosol-radiation interactions. The results show that BC emitted from South Asian biomass burning significantly enhances snowmelt over the TP. The strongest impacts occur in spring, during which SCF and SD are decreased by 9.7% and 4.6 cm, respectively. Source attribution reveals that forest fires dominate TP spring snowmelt, contributing 42.1% and 41.1% to the decreases in SCF and SD, respectively. Agricultural waste burning is the primary contributor in autumn, accounting for 67.7% and 46.0% of the decrease in SCF and SD, respectively. Under the SSP1-2.6 and SSP5-8.5 scenarios, BC emissions from South Asian biomass burning will lead to a 6.9% and 3.5 cm reduction, and an 11.5% and 7.3 cm reduction, respectively, in SCF and SD in spring over the TP in 2060. We show that SOS substantially amplifies BC-induced snowmelt through the aerosol lensing effect, reducing the annual mean SCF and SD from 5.2% to 6.4% and from 2.7 cm to 4.3 cm in 2020, respectively. These findings highlight the critical roles of source-specific emission control and multi-pollutant mitigation strategies in alleviating cryospheric degradation and safeguarding water resources in the Asian Water Tower.

来源平台：ATMOSPHERIC RESEARCH