| Summary: | The worldwide aerosol robotic network (AERONET) of ground-based radiometers was developed (in part) as a satellite validation tool (Holben et al. 1998). These sites utilize spectral sky-scanning radiometers, providing more information for aerosol retrievals than conventional sunphotometer measurements. The use of the almucantar sky radiance scans in conjunction with the aerosol optical thicknesses are the basis of the AERONET Dubovik retrievals, which provide the aerosol size distribution and the refractive index at four wavelengths (Dubovik and King 2000). The accuracy of the Dubovik retrieval has been assessed with the retrieval of synthetic data (Dubovik et al. 2000), but an assessment utilizing independent measurements is desirable. Hence, the AERONET retrievals are used here as input to a discrete-ordinates radiative transfer model (DISORT, Stamnes et al. 1988) utilizing 12 computational streams to calculate the solar radiation at the surface, and the results are compared to co-located surface measurements. Included in the comparison are principle plane radiance measurements from the Cimel sunphotometer, irradiance measurements from the Multi-filter Rotating Shadowband Radiometer (MFRSR, Michalsky et al. 2001), and irradiance measurements from the Rotating Shadowband Spectroradiometer (RSS, Harrison et al. 1999).
|
|---|