Assessing the Radiative Impact of a Dust Storm using Satellite Remote Sensing and Radiaitve Transfer Calculations

This study conducts a detailed examination of a dust storm on June 21, 2007, which originated from the Sahara Desert and was transported westerly by the mid-level winds over the Atlantic Ocean. A four stream radiative transfer model (RTM) was used to compute dust radiative effects and atmospheric heating rates. We use the CALIPSO and Cloudsat satellite products as critical inputs into the RTM along with nearby AERONET station measurements. AERONET provides the additional critical aerosol inputs of aerosol optical depth, effective radius, single scatter albedo, and asymmetry parameter. Finally, since low-level clouds lie beneath portions of the dust storm, Cloudsat is used to provide the model with cloud optical depth. The radiative transfer calculations show that these large dust storms can influence very significant SW heating of the atmosphere and dust radiative forcing values. The LW heating and dust radiative forcing is much smaller for this dust storm but still not negligible. Lastly, large differences are seen with the heating rate and radiative effect in the profiles with cloud beneath dust compared to the cloud-free dusty profiles.