Fine and Coarse Mode Aerosols in Southern Great Plains Multi-Filter Rotating Shadowband Radiometer Datasets

We present results obtained using the new version of the multi-filter rotating shadowband radiometer (MFRSR) data analysis algorithm (Alexandrov et al. 2005). This algorithm allows the partition of aerosol optical thickness (AOT) into fine and coarse aerosol modes and to retrieve the fine mode effective radius (reff). A bimodal gamma distribution is used as the aerosol particle size model. The algorithm has been used for analysis of a multi-year dataset from the local MFRSR network at the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement Climate Research Facility (ACRF) Southern Great Plains (SGP) site. The retrieved aerosol parameters are compared with the corresponding AERONET almucantar retrieval results derived from a CIMEL sunphotometer collocated with the MFRSR at the SGP Central Facility. A constrained variant of the algorithm (zero NO2 column values) has been used to define the range of physically justified values of the fine mode effective radius, and for comparison with AERONET particle size retrievals.