| The subject of this dissertation centers on a retrieval scheme which can be used to derive the aerosol phase function and single scattering albedo from the sky radiance over land. The retrieval scheme iteratively corrects the aerosol volume scattering function, a product of the single scattering albedo and the phase function, based on the difference between the measured sky radiance and the radiance calculated by solving the radiative transfer equation. The retrieval scheme was first tested under ideal conditions, i.e., the approximations made in the retrieval algorithm totally agree with actual conditions assumed in creating the pseudo data for sky radiance. It was then tested, through simulation, under more realistic conditions to assess its susceptibility to various measurement errors and effects of conditions not recognized in the retrieval algorithm. These simulations show that, in most cases, this scheme can retrieve the aerosol single scattering albedo with high accuracy (within 1%), and can therefore be used to identify absorbing aerosols. It can also produce meaningful retrievals of most aerosol phase functions: less than 5% error at 865 nm and less than 10% at 443 nm in most cases. However, disappointing results in both the single scattering albedo and the scattering phase function occur at 443 nm, when there are large calibration errors in the radiometer that measures the sky radiance or when the land reflection properties are drastically inhomogeneous. |
