Aerosol vertical profile retrievals using passive radiometric measurements

Aerosol vertical profiles in the lowest 1 km of the atmosphere are not very well studied due to technology limitations (e.g. LIDARs) and air space restrictions (e.g. manned and unmanned aircrafts). This study investigates sensitivity of the radiance measurements to the aerosol profiles from the standard columnar almucantar and direct sun measurements combined with low elevation sky scanning (from the horizon to zenith direction). Sensitivity studies are conducted for the sun-sky radiometer filter bands deployed within AERONET. AErosol RObotic NETwork (AERONET) is a network of sun-sky-moon photometers that measure solar radiation at 9 wavelength bands (centered at 340, 380, 440, 500, 675, 870, 937, 1020, 1640 nm, 2-10 nm except 25 nm for 1640 nm FWHM filter transmission). The main AERONET products are columnar aerosol optical depth, Angstrom exponent (from direct sun measurements), single scattering albedo and size distribution (from Almucantar and hybrid scans). The additional products investigated in this study are vertical volume density and aerosol extinction coefficient profiles. GRASP (with the plane parallel radiative transfer model) is initially used to simulate scattered sky radiances and conduct aerosol profile inversions. Several aerosol models and loadings are investigating as well as aerosol volume density profiles.