Improved method of cloud characterization from satellite measurements of horizontal atmospheric transmissivity

The satellite borne Stratospheric Aerosol and Gas Experiment (SAGE) instrument measures the attenuation of solar radiation through the atmosphere at sunrise and sunset events. These measurements contain information about the gases, aerosols and clouds responsible for the observed attenuation at different wavelengths. This work focuses on methods to extract cloud information from the measurements.;Three approaches are discussed using SAGE measurements. The first approach identifies cloud occurrences by comparing the retrieved atmospheric extinction at two wavelengths. This method was applied to 17 years of data to analyze the global and temporal distributions of upper tropospheric clouds and stratospheric volcanic aerosols. The second approach taken was to simulate SAGE transmittance data with a wide range of inputs to a forward model and generate a library of SAGE transmittance data. The resulting web-based library serves as a reference source for comparisons with observed events. The third approach investigated is a direct inversion of cloud characteristics from observed transmittances. Case studies showed that the cloud fields so derived produced transmittance profiles that matched the observations. A limitation of the inversion method is that it requires a known set of ray traces; if such information is not available a priori, an iterative process has to be applied.*.;*This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation).