This investigation seeks to perform theory and data analysis to validate a technique for remotely sensing the density and temperature of the neutral atmosphere at altitudes between 100 and 600 km. The technique uses ground-based measurements of optical emissions from the atmosphere during twilight conditions, the electron density is also an important input. The proposed study will use optical measurements from McDonald Observatory in Texas and radar measurements from nearby sites in New Mexico and Colorado. The interpretation of the optical measurements is to be performed with the aid of a computer model called FLIP (Field Line Interhemispheric Plasma) which takes into account the sources and sinks of emissions from atomic oxygen.
