Role of sulphate and carbonaceous aerosols on the radiative effects of aerosols over a remote high-altitude site Lachung in the Eastern Himalayas

The rapid changes in the pattern of atmospheric warming as well degradation glaciers Himalayas point to inevitability accurate source characterization and quantification impact aerosols. In this regard, optical chemical properties aerosols, their role radiative effects are examined over a remote high-altitude site Lachung (27.4°N, 88.4°E, 2700 m a.s.l.) eastern during August-2018 February-2020. It is found that sulphate (SO42−) carbonaceous aerosols (both organic carbon - OC elemental EC) significantly contribute total aerosol mass loading winter (DJF) spring (MAM), resulting high values scattering absorption coefficients. Aerosol single albedo (SSA) relatively higher (> 0.85) due amount (OC/EC > 8). However, SSA ~ 0.8 despite SO42− concentrations (SO42−/EC 4.0 SO42−/OC 1.0) than winter. A reverse seen summer-monsoon (JJAS) having lower SO42−/EC < 2 0.5, low ~0.64. seasonal direct forcing top atmosphere (DRFTOA) −2.9 ± 1.2 Wm−2 period abundant −2.8 0.5 spring. combined effect on surface cooling highest (−16.7 4.9 Wm−2). DRF also 34% (13.8 4.5 Wm−2, which translates an heating rate 0.39 K day-1), influenced by heterogeneous sources composition Himalayan transport from Indo-Gangetic Plains India.