One of the major goals of the CEDAR program is to develop a global technique for determining the height distribution and its variation with time of the different atmospheric constituents in the upper atmosphere. One promising technique which is being pursued is to use the variation in emission intensity associated with atomic oxygen and molecular nitrogen during twilight to provide this information. The work outlined in this project will use modeling techniques to invert these twilight observations into constituent density height distributions. The success of this approach will lead to a simple technique which can be widely used around the globe to determine the compositional dynamics of the upper atmosphere. 3/3/89//
