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      https://www.ias.ac.in/article/fulltext/jess/118/01/0041-0048

    • Keywords

       

      Aerosol optical depth; ˚Angstrom parameters; meteorological parameters; airmass back trajectories.

    • Abstract

       

      First time observations of spectral aerosol optical depths (AODs) at Mohal (31.9°N, 77.11°E; altitude 1154m amsl) in the Kullu valley, located in the northwestern Indian Himalayan region, have been carried out during Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB), as a part of the Indian Space Research Organisation–Geosphere Biosphere Program (ISRO–GBP). AODs at six wavelengths are obtained using Microtops-II Sunphotometer and Ozonometer. The monthly mean values of AOD at 500 nm are found to be 0.27 ± 0.04 and 0.24 ± 0.02 during March and April, 2006 respectively. However, their monthly mean values are 0.33 ± 0.04 at 380 nm and 0.20 ± 0.03 nm at 870 nm during March 2006 and 0.31 ± 0.3 at 380 nm and 0.17 ± 0.2 at 870 nm during April 2006, showing a gradual decrease in AOD with wavelength. The ˚Angstrom wavelength exponent '𝛼' had a mean value of 0.72 ± 0.05, implying reduced dominance of fine particles. Further, the afternoon AOD values are higher as compared to forenoon values by ∼33.0% during March and by ∼9.0% during April 2006 and are attributed to the pollutant lifted up from the valley by the evolving boundary layer. Besides the long-range transportation of aerosol particles by airmass from the Great Sahara and the Thar Desert regions to the observing site, the high values of AODs have also been influenced by biomass burning and frequent incidents of forest fire at local levels.

    • Author Affiliations

       

      Jagdish C Kuniyal1 Alpana Thakur1 Harinder K Thakur1 Sanjeev Sharma1 P Pant2 Pan S Rawat3 K Krishna Moorthy4

      1. G.B. Pant Institute of Himalayan Environment and Development, Himachal Unit, Mohal-Kullu 175 126, India.
      2. Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 002, India.
      3. Department of Physics, D.S.B. Campus, Kumaun University, Nainital, Uttarakhand, India.
      4. Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 659 022, India.
    • Dates

       
  • Journal of Earth System Science | News

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