Impacts of Aerosol Loading in the Hindu Kush Himalayan Region Based on MERRA-2 Reanalysis Data

The impacts of climate change have severely affected geosphere, biosphere and cryosphere ecosystems in the Hindu Kush Himalayan (HKH) region. impact has been accelerating further during last few decades due to rapid increase anthropogenic activities such as modernization, industrialization urbanization, along with energy demands. In view this, present work attempts examine aerosol optical depth (AOD) over HKH region using long-term homogeneous MERRA-2 reanalysis data from January, 1980 December, 2020. AOD trends are examined statistically student’s t-test (t). Due a vast landmass, fragile topography harsh climatic conditions, we categorized into three sub-regions, namely, northwestern Karakoram (HKH1), Central (HKH2) southeastern Himalaya Tibetan Plateau (HKH3). Among significant enhancement is observed at several potential sites HKH2 region, Pokhara, Nainital, Shimla Dehradun by 55.75 × 10?4 ± 3.76 10?4, 53.15 3.94 51.53 4.99 39.16 4.08 year?1 (550 nm), respectively, correlation coefficients (Rs) 0.86 0.93. However, sub-regional scale, HKH1, HKH3 exhibit 23.33 2.28 32.20 2.58 9.48 1.21 year?1, respectively. estimated (t > 7.0) R 0.81 0.91. Seasonally, study also shows strong positive located Dehradun, minimum 19.81 3.38 maximum 72.95 4.89 statistical significance. addition, there increasing all high-altitude background seasons.