Wintertime aerosol optical properties and radiative forcing over rohtak

The present work was focused on analyzing the aerosol optical properties over Rohtak during winter season from December 2015 to February 2016 using sky-radiometer data. The results reveal that AOD shows strong spectral dependence. Higher value of AOD was observed during January at all wavelengths. The monthly mean AOD at 500 nm were found to be 0.44±0.23, 0.80±0.37 and 0.57±0.34 for December, January and February, respectively with seasonal average of 0.63±0.36. Higher values of Alpha predominantly ranged from 0.8-1.4 indicates the relative dominance of fine mode particles to the aerosol loading over the station. Volume size distribution exhibits bimodal distribution with dominant fine mode around 0.17 µm and coarse mode around 11 µm. The derived aerosol optical properties are used in SBDART model for aerosol radiative forcing estimation. Monthly mean atmospheric radiative forcing values are +7, +14 and +12 Wm2 for December, January and February respectively.