Summary
Atmospheric gravity waves (AGWs), which are generated in the lower atmosphere, transport significant amount of energy and momentum into the mesosphere and lower thermosphere. Among many parameters to characterize AGWs, horizontal phase velocity is very important to discuss the vertical propagation. Airglow imaging is a useful technique for investigating the horizontal structures of AGWs around mesopause. ANGWIN (Antarctic Gravity Wave Imaging/Instrument Network) is an international airglow imager (and other instruments) network in the Antarctic, started in 2011. It seeks to reveal characteristics of mesospheric gravity waves, and to study sources, propagation, breaking of the gravity waves over the Antarctic and the effects on general circulation and upper atmosphere.In this study, we compared distributions of horizontal phase velocity of the gravity waves at around 90 km altitude over different locations using our new statistical analysis method using 3-D Fourier transform, developed by Matsuda et al. (2014). The comparison has been carried out for the airglow imagers at four stations at Syowa (69S, 40E), Halley (76S, 27W), Davis (69S, 78E) and McMurdo (78S, 156E) out of the ANGWIN imagers, for the observation period between April 6 and May 21 in 2013. Not only horizontal distribution of propagation, gravity wave energies can also be quantitatively compared, indicating a smaller GW activity in higher latitudes. The presentation will be focused on showing the performance of the new statistical technique for studying gravity wave.
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