We propose to conduct a study of the sources due to mesoscale variability of gravity waves at mesospheric heights. The mesospheric wind data for this study will be obtained from an HF radar installed on the island of Kauai, Hawaii in September of 1990. Gravity wave activity observed from this radar will be examined with reference to possible frontal, convective, and jet stream wave sources. We intend to use synoptic, radiosonde, and satellite imaging data in the search for these sources. We will also conduct a critical examination of the spaced antenna drift (SAD) technique in regard to measuring winds in the middle atmosphere.