Publications

Saheb, SD; Kant, Y; Mitra, D (2016). Variability of aerosol optical depth and aerosol radiative forcing over North West Himalayan region. REMOTE SENSING OF THE ATMOSPHERE, CLOUDS, AND PRECIPITATION VI, 9876, UNSP 98762M.

Abstract
In recent years, the aerosol loading in India is increasing that has significant impact on the weather/climatic conditions. The present study discusses the analysis of temporal (monthly & seasonal) variation of aerosol optical depth(AOD) by the ground based observations from sun photometer and estimate the aerosol radiative forcing and heating rate over selected station Dehradun in North western Himalayas, India during 2015. The in-situ measurements data illustrate that the maximum seasonal average AOD observed during summer season AOD at 500nm approximate to 0.59 +/- 0.27 with an average angstrom exponent, alpha approximate to 0.86 while minimum during winter season AOD at 500nm approximate to 0.33 +/- 0.10 with angstrom exponent, alpha approximate to 1.18. The MODIS & MISR derived AOD was also compared with the ground measured values and are good to be in good agreement. Analysis of air mass back trajectories using HYSPLIT model reveal that the transportation of desert dust during summer months. The Optical Properties of Aerosols and clouds (OPAC) model was used to compute the aerosol optical properties like single scattering albedo (SSA), Angstrom coefficient (alpha) and Asymmetry(g) parameter for each day of measurement and they are incorporated in a Discrete Ordinate Radiative Transfer model, i.e Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) to estimate the direct short-wave (0.25 to 4 mu m) Aerosol Radiative forcing at the Surface (SUR), the top-of-atmosphere (TOA) and Atmosphere (ATM). The maximum Aerosol Radiative Forcing (ARF) was observed during summer months at SUR approximate to -56.42 w/m(2), at TOA approximate to -21.62 w/m(2) whereas in ATM approximate to +34.79 w/m(2) with corresponding to heating rate 1.24 degrees C/day with in lower atmosphere.

DOI:
10.1117/12.2223641

ISSN:
0277-786X