Direct radiative effects of an unseasonal dust storm at a western Indo Gangetic Plain station Delhi in ultraviolet, shortwave, and longwave regions

The aerosol direct radiative effects (DRE) in the ultraviolet, shortwave, and longwave range due to an unusual dust storm during 21 March 2012 have been quantified from surface measurements of aerosol optical depth (AOD) and radiation fluxes at Delhi, a western Indo Gangetic Plain station. The intrusion of dust over Delhi caused an increase in daily average AOD at 500nm from 0.6 to 0.8, with a corresponding decrease in Angstrom exponent from 0.4 to subzero value. The dust severely affected the incoming solar radiation flux in the UV, shortwave, and longwave regions. The DRE at surface in the UV and shortwave regions decreased from -4.6 to -5.9 Wm(-2) and from -68 to -86 Wm(-2), respectively, while the longwave DRE increased from 27 to 45 Wm(-2).