A Two-dimensional Spectral Analysis of Short Period Gravity Waves Imaged in the OI (557.7 nm) and Near Infrared OH Nightglow Emissions Over Arecibo, Puerto Rico

In January 1993 an extensive set of radar and optical data was gathered from various key sites around the world during a coordinated “10 Day Run” designed to investigate the coupled dynamic behavior of the upper atmosphere on a large, medium and small scale. As part of this campaign an all‐sky CCD imaging system was operated at Arecibo Observatory, Puerto Rico, to help quantify the response of the low latitude mesosphere‐thermosphere system to short period (\u3c1 hour) gravity waves. Measurements of the OI(557.7 nm) and near infrared OH nightglow emissions were made in conjunction with photometric and ISR radar soundings and revealed an abundance of small‐scale structure in the 80–100 km range. In this letter we apply two‐dimensional spectral analysis techniques to aid in the interpretation of a complex set of image data that consisted of two intersecting quasi‐monochromatic gravity wave patterns progressing on approximately orthogonal headings. An investigation of the spectral content and temporal evolution of these wave motions at each emission altitude is presented