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Large-amplitude Inertia Gravity Waves over Syowa Station: Comparison of PANSY Radar and ERA5 Reanalysis Data
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  • Lihito Yoshida,
  • Yoshihiro Tomikawa,
  • Mitsumu K. Ejiri,
  • Masaki Tsutsumi,
  • Masashi Kohma,
  • Kaoru Sato
Lihito Yoshida
The Graduate University for Advanced Studies, SOKENDAI

Corresponding Author:yoshida.rihito@nipr.ac.jp

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Yoshihiro Tomikawa
National Institute of Polar Research
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Mitsumu K. Ejiri
National Institute of Polar Research
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Masaki Tsutsumi
National Institute of Polar Research
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Masashi Kohma
University of Tokyo
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Kaoru Sato
The University of Tokyo
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Abstract

We examined large-amplitude inertia gravity waves (GWs) over Syowa Station, Antarctica, comparing PANSY radar data and ERA5 reanalysis from October 2015 to September 2016. Focusing on large-amplitude events with a large absolute momentum flux (AMF), hodograph analysis was applied to estimate the wave parameters and found that the percentage of these waves with a downward phase velocity increased with altitude. Vertical wavelengths shortened, intrinsic periods lengthened, and horizontal wavelengths became longer with increasing altitude. Southward propagation of GWs was predominant in the stratosphere. Compared to a previous study, the wave parameters’ altitude variation remained consistent, but horizontal and vertical wavelengths were longer in this study. ERA5 underestimated AMF by about 1/5 between 5 and 12.5 km, with a larger underestimation at higher altitudes. The underestimation was related to the power spectra of horizontal and vertical winds, particularly vertical winds. The greater underestimation in the stratosphere might be due to ERA5’s vertical grid spacing and shorter vertical wavelengths of dominant GWs.