Observations of Atmospheric Gravity Waves in Airglow Over Adelaide

This paper presents the statistical results of the propagation characteristics of largescale gravity waves observed by OH and OI airglow during the years from 1995 to 2001 in Adelaide, Australia （34.5°S, 138.5°E）. The propagation parameters were obtained through the three-channel maximum entropy method. Totally 48 gravity wave events were identified by the OH airglow observation and 29 events were identified by OI. The periods and horizontal phase speeds of these gravity waves peak at about 68 min and 36 m/s, and the gravity waves shows an obvious dominating direction of propagating south-eastward. The mean elevation is 8°- 10°, which shows the nearly horizontal propagation trends. It was also found that an up-going gravity wave event was observed nearly simultaneously by OH and OI. However, in most cases, the gravity waves cannot be observed simultaneously by OH and OI observations, because of the errors of the instruments or the effects of strong wind shears on gravity waves in the mesopause region.