Evidence of Increasing trend of snow cover in himalayas implicate snow darkening

While persistent snow cover traditionally preserves high surface albedo and buffers against early glacier melt, shifting precipitation regimes and light-absorbing aerosols are disrupting this protective mechanism. MODIS data indicates that the pre-monsoon snow season in the North Western Himalayas (NWH) extended by 7±3 days between 2000 and 2020. This extension is driven by large-scale dynamics, specifically moisture convergence and a deepened geopotential trough at 200 hPa.Crucially, snowfall resulting from these conditions enhances the wet deposition of atmospheric aerosols. As these aerosols resurface, they diminish the albedo benefits of fresh snow by 20%. This establishes a critical feedback loop wherein increased snowfall paradoxically facilitates surface darkening and accelerates melt. This snow-aerosol interaction necessitates a revision of surface energy balance models to accurately project future regional water availability.