Summary
A decade of radiosonde observations of wind and temperature in the troposphere and lower stratosphere have made it possible to compile a climatology of low-frequency gravity waves above Davis, Antarctica (69°S, 78°E). Wave characteristics, extracted using wavelet analysis [Zink and Vincent, 2001], show strong seasonal and height variations. In particular, the high prevalence of down-going waves in the winter lower stratosphere previously identified at other Antarctic sites [Moffat-Griffin et al. 2011; Yoshiki and Sato, 2000] has been shown to exist at Davis. Investigations of the vertical structure and seasonal variation of down-going wave percentages suggest a relationship to the background zonal wind and temperature structure. Statistical distributions of the characteristics of the up and down-going waves show strong similarities suggesting a common source. It has been suggested [Sato and Yoshiki, 2008] that imbalance processes in the polar night jet may play a role in their production. This possibility is considered along with the propagation characteristics of the waves to explore their role in the dynamics of the polar stratosphere. References: Moffat-Griffin, T., R. E. Hibbins, M. J. Jarvis and S. R. Colwell, Seasonal variations of gravity wave activity in the lower stratosphere over an Antarctic Peninsula station, J. Geophys. Res., 116, D14111, doi:10.1029/2010JD015349, 2011. Sato, K. And M. Yoshiki, Gravity wave generation around the polar vortex in the stratosphere revealed by 3-hourly radiosonde observations at Syowa station, J. Atmos. Sci., 65, 3719-3735, 2008. Yoshiki, M. And K. Sato, A statistical study of gravity waves in the polar regions based on operational radiosonde data, J. Geophys. Res., 105, D14, 17995-18011, 2000. Zink, F. and R. A. Vincent, Wavelet analysis of stratospheric gravity wave packets over Macquarie Island 1. Wave parameters, J. Geophys. Res., 106, 10275-10288, 2001.
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