A 2-DIMENSIONAL SPECTRAL-ANALYSIS OF SHORT-PERIOD GRAVITY-WAVES IMAGED IN THE OI(557.7 NM) AND NEAR-INFRA-RED OH NIGHTGLOW EMISSIONS OVER ARECIBO, PUERTO-RICO

In January 1993 an extensive set of radar and optical data was gathere d from various key sites around the world during a coordinated ''10 Da y Run'' designed to investigate the coupled dynamic behavior of the up per atmosphere on a large, medium and small scale. As part of this cam paign an all-sky CCD imaging system was operated at Arecibo Observator y, Puerto Rico, to help quantify the response of the low latitude meso sphere-thermosphere system to short period (<1 hour) gravity waves. Me asurements of the OI(557.7 nm) and near infrared OH nightglow emission s were made in conjunction with photometric and ISR radar soundings an d revealed an abundance of small-scale structure in the 80-100 km rang e. In this letter we apply two-dimensional spectral analysis technique s to aid in the interpretation of a complex set of image data that con sisted of two intersecting quasi-monochromatic gravity wave patterns p rogressing on approximately orthogonal headings. An investigation of t he spectral content and temporal evolution of these wave motions at ea ch emission altitude is presented.