GWIM: a satellite instrument for gravity wave characterization

摘要

Gravity waves are ubiquitous in the Earth's atmosphere transporting energy and momentum between regions. GWIM is a satellite instrument that will use airglow intensity variations to measure gravity wave parameters. A major interest lies in the correlation of the presence of gravity waves with their sources near the surface or in the lower atmosphere. The specific airglow emissions were chosen because of their high radiance and their low susceptibility to contamination by moonlight scattered from clouds. GWIM consists of four nadir-looking imagers, one each for signal and background for each of the two emissions. The field of each imager will be 175 km cross-track by 80 km along the track. An integration time of about ten seconds is required to achieve the required signal-to-noise ratio. To prevent image smearing due to the effects of satellite motion and the rotation of the earth, GWIM will operate in snapshot mode with an exposure time of about 0.25 second followed by on-board shift-and-add. GWIM is being considered for flight as part of the payload of EQUARS, a Brazilian satellite planned for launch into a near equatorial orbit in 2007.