| Summary: | Our purpose of this study is to investigate the characteristics of sporadic and large amplitude gravity wave (GW) events that can have a large impact on the overall momentum transport, and also to investigate how well the reanalysis data reproduces the GW events in the Antarctic. We used the PANSY radar for the observation data and the ERA5 reanalysis for the reanalysis data. The PANSY radar, which was installed at Syowa Station (69°S,40°E) in 2011, observes vertical profiles of three-dimensional winds in the troposphere and lower stratosphere with high accuracy and fine temporal and vertical resolution (Sato et al., 2014). The ERA5 reanalysis is the latest meteorological reanalysis dataset provided by the European Centre for Medium-Range Weather Forecasts. We use three dimensional winds of the PANSY radar and the ERA5 reanalysis during the period of October 2015 to September 2016, in which the PANSY radar was continuously operated (Minamihara et al.,2018). As a result, we found many similar wave-like structures between the PANSY radar and the ERA5 reanalysis. In order to examine the propagation characteristics of inertia-GWs, we use a hodograph analysis. Since the GWs are assumed to be quasi-monochromatic in the hodograph analysis, three dimensional winds are separated into components with upward and downward phase velocities by a two-dimensional Fourier transform. This procedure makes it possible to extract quasi-monochromatic GW events that were previously impossible to extract. We also investigate power spectra of momentum flux.
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