Earth Planets Space, Vol. 59 (No. 5), pp. 421-428, 2007
Shin Suzuki1, Kazuo Shiokawa1, Yuichi Otsuka1, Tadahiko Ogawa1, Minoru Kubota2, Masaki Tsutsumi3, Takuji Nakamura4, and David C. Fritts5
1Solar-Terrestrial Environment Laboratory, Nagoya University,
Toyokawai, Aichi 442-8507, Japan
2National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
3National Institute of Polar Research, Itabashi, Tokyo 173-8515, Japan
4Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
5Colorado Research Associates, Division of Northwest Research Associates, Boulder, Colorado 80301,USA
(Received September 28, 2006; Revised December 28, 2006; Accepted January 24, 2007; Online published June 8, 2007)
We report procedures to identify small-scale (20-100 km) atmospheric gravity waves from OH airglow images to estimate momentum fluxes carried by the waves. We also deduce contamination of background continuum emission in OH image, by comparing a simultaneous observation of OH lines measured by the Spectral Airglow Temperature Imager (SATI). We applied the procedures to a one-night dataset obtained at Shigaraki, Japan (34.9°N, 136.1°E) on November 19, 1999. The background wind, which is essential for deriving the intrinsic parameters of gravity waves, was measured by the Middle and Upper Atmosphere (MU) radar. Contamination of background continuum emission with the OH filter was deduced to be 30%. From these procedures, we found that the gravity waves identified in the OH images were mainly propagating southward or southeastward with horizontal wavelengths of 60-90 km and apparent phase speeds of 40-80 m/s. The estimated momentum fluxes on this night was 1-15 m2 s-2, with an average of 4.9 m2 s-2.
Key words: Gravity wave, momentum flux, airglow image, mesosphere and lower thermosphere.