Abstract: Ground based measurement of aerosol optical depth (AOD) and black carbon (BC) aerosol were carried out on the foothills of the three important selected glaciers (i.e., Parbati, Hamta and Beas Kund) in winter season in the northwestern Indian Himalayan Region. The AOD values were found to be in the range of 0.05-0.19. The aerosol loading was observed relatively to be higher (0.15) on 10 November 2014. Besides the biomass burning and frequent incidents of forest fire at local levels, long-range transportation of aerosol particles by air mass from the desert region also contribute to aerosol loading at observing sites. The average value of BC concentration ranges from 283 to 2026 ng m−3. BC concentration increases more than three times during morning and evening compared to night hours, in addition to shallow boundary layer and a larger possibility of BC intrusion from it during morning and evening. Variations of BC shows high concentration during winter dry season associated with the air masses predominantly coming from Indian plain rich in carbonaceous aerosols. The BC concentration is found to have relationship with anthropogenic activities, fossil fuel burning and biomass burning which has been observed in past in this region.
Keywords: Aerosol optical depth, Black carbon, Air mass back trajectory, Northwestern Indian Himalaya