Quantum theory of the interaction of radiation with matter, spectral line shapes, widths, and pressure shifts for atmospheric molecules. Theoretical and experimental studies of remote sensing of the Earth's troposphere, stratosphere, and ionosphere, and planetary atmospheres. Measurement and modeling of tropospheric pollutant gases. Atmospheric modeling and simulation code development and maintenance. Expert Systems. Electron density and molecular density profiles for terrestrial atmosphere. Ionospheric modeling and prediction. Radiative transfer and its applications to the Greenhouse effect. Database structure and design for application to physical data.