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Atmospheric dry deposition of black carbon (BC) is a significant but poorly understood and inadequately described process in aerosol-climate models. The 40-year detailed dry deposition velocities of hydrophilic BC over China from 1981 to 2020 were systematically studied based on the MERRA-2 reanalysis data, which hopefully will be beneficial for its applications in atmospheric systems for climate and air quality. The average dry deposition flux of hydrophilic BC over China was 0.00059 ± 0.00014 μg m−2 s−1, while its dry deposition velocity was estimated to be 0.00051 ± 0.00004 m s−1. The monthly mean dry deposition fluxes of hydrophilic BC varied nearly 1.5 fold, ranging from the lowest 0.00046 ± 0.00011 μg m−2 s−1 in August to the highest 0.00068 ± 0.00019 μg m−2 s−1 in January. The spring season had the highest mean dry deposition flux of hydrophilic BC, followed by summer and winter, whereas autumn showed relatively weaker dry deposition flux. The mean dry deposition velocities of hydrophilic BC over the Beijing-Tianjin-Hebei region, Yangtze River Delta, Pearl River Delta and Tibet Plateau were estimated to be 0.00042 ± 0.00004, 0.00042 ± 0.00004, 0.00051 ± 0.00006 and 0.00078 ± 0.00005 m s−1, respectively. The monthly and seasonal patterns of dry deposition velocities of hydrophilic BC differed from each other in different regions, and high air temperature or surface wind speed seemed to fortify dry deposition velocities of hydrophilic BC. Our study pointed to high dry deposition flux of hydrophilic BC in the northern China Plain and Sichuan Basin but large dry deposition velocities in the Tibet Plateau region. [ABSTRACT FROM AUTHOR]

The aerosol‐induced snow albedo effect (SAE) and its feedback on the dust emission over the Tibetan Plateau are investigated using the regional climate model (RegCM4.6) coupled with the SNow, ICe, and Aerosol Radiative model. The deposition of absorbing aerosols (black carbon and dust) decreases the albedo of snow over the Himalayan‐Tibetan region, which results in significant surface warming of 1–4 K. This aerosol‐induced surface warming and accelerated snow melting decreased fractional snow cover by 8% and number of snow cover days by 20 days over the region. Compared to the control simulation, this early and more exposure of nonvegetated land resulted in the increase of the dust emission flux by 60% over central Tibet and therefore the columnar dust loading by 10%–40%. This effect alone results in a surface cooling of −4 Wm−2 and also increases the occurrence of dust events by 10%–20%. Therefore, the snow darkening effect due to the deposition of black carbon and dust increases the local emission of dust aerosols, which further increases the aerosol‐induced snow melting and thus perturbs the air quality and radiation balance over the high mountains of Asia. Key Points: Aerosol‐induced snow darkening decreases snow cover over the Himalayan‐Tibetan regionAerosol radiative effects on snow strengthens the local emission of dust aerosolsThe feedback of aerosol‐induced snow darkening enhances the direct effect of dust aerosols [ABSTRACT FROM AUTHOR]

• The Himalayan geothermal Belt is manifested with hundreds of springs with issuing surface temperatures of 27 °C - 96 °C with slightly acidic to moderately alkaline (pH = 4.5 – 9.4) in nature. • The investigated geothermal systems are composed of a low to moderate enthalpy sources. • Puga, Chumathang, and Gaik thermal springs lie in the western part of HGB that correlate with the Yangbajing thermal spring in Tibet (the eastern part of HGB). • We have projected that the power potential of HGB is 23,622 MW e which can help to mitigate 1.4 × 108 tCO 2. We have compiled geochemical dataset of springs (Thermal and Cold) from the Himalayan Geothermal Belt (HGB), shows slightly acidic to moderately alkaline (pH = 4.5 – 9.4) in nature with an emerging surface temperature of 27 °C – 96 °C. The calculated reservoir temperature ranged in between 78 °C – 159 °C categorize the HGB as a low- to a moderate-enthalpy geothermal system. It was observed that geochemical facies of thermal springs dominated by the Ca-HCO 3 , Na-HCO 3 and Na-Cl composition while cold springs are abundant in Ca-Mg-HCO 3 and Ca-Mg-SO 4. Interestingly, Piper diagram inferred that Puga, Chumathang, and Gaik thermal springs, lies in the western part of HGB that correlate with the Yangbajing thermal spring in Tibet (eastern part of HGB). Tectonically, the HGB is associated with the continental collision zone, shallow crustal melting, and high heat-producing younger granite (70 mW/m2 to > 400 mW/m2); therefore, the resultant geothermal gradient along the HGB is more than 200 °C/km. The present research documents that HGB have potential to reduce CO 2 and BC emissions by taping the geothermal energy for power generation and we have projected that the power potential of HGB is 23,622 MW e that can help to mitigate 1.4 × 108 tCO 2. [ABSTRACT FROM AUTHOR]