Summary
Atmospheric gravity waves (AGWs), which are generated in the lower atmosphere, transport significant amount of energyand momentum into the mesosphere and lower thermosphere and cause the mean wind accelerations in the mesosphere. Thismomentum deposit drives the general circulation and affects the temperature structure. Among many parameters to characterizeAGWs, horizontal phase velocity is very important to discuss their vertical propagation. Airglow imaging is a useful techniquefor investigating the horizontal structures of AGWs around mesopause. An international airglow imager (and other instruments)network in the Antarctic, named ANGWIN (Antarctic Gravity Wave Imaging/Instrument Network) was started in 2011. Itspurpose is to understand characteristics of mesospheric gravity waves, and to study sources, propagation, breaking of the gravitywaves over the Antarctic and the effects on general circulation and upper atmosphere.In this study, we compared distributions of horizontal phase velocities of gravity waves at around 90 km altitude over differentlocations using our new statistical analysis method based on 3-D Fourier transform, developed by Matsuda et al. (2014). Thecomparison has been carried out for the airglow imagers at four stations, that are 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 21in 2013. Not only horizontal propagation characteristics, gravity wave energies can also be quantitatively compared, indicatinga smaller GW activity in higher latitudes. The presentation will be focused on showing the performance of the new statisticaltechnique for studying gravity waves.
Related projects
