[A-AS10] Stratosphere-troposphere (Atmospheric) Processes And their Role in Climate

[AAS10-P05] Simultaneous observation of near-inertial gravity waves by a long-duration balloon and the PANSY radar over Antarctica

*Yoshihiro Tomikawa¹, Isao Murata², Masashi Kohma³, Kaoru Sato³ (1.National Institute of Polar Research, 2.Tohoku University, 3.The University of Tokyo)

Keywords:Inertia gravity wave, Antarctic, Super-pressure balloon, PANSY radar

Simultaneous observations using a long-duration balloon and a large aperture atmospheric radar, PANSY, were performed at Syowa Station, Antarctica, from January to February 2022. They captured near-inertial gravity waves (NIGWs) in the lower stratosphere. The analysis using both datasets revealed that the NIGWs with an upward group velocity, a vertical wavelength of 2.4 km, and a ground-based period of about 10 hours propagated eastward above Syowa Station. Comparison with the latest reanalysis ERA5 showed that although the NIGWs over Syowa Station were qualitatively represented, their amplitudes were underestimated in ERA5. In addition, as the NIGWs propagated eastward, they were no longer captured even qualitatively by ERA5. This suggests that as the NIGWs propagated eastward, they approached the critical level and could no longer be represented by ERA5 because the vertical wavelengths became shorter. This result implies the difficulty to explicitly represent the behavior of NIGWs near the critical level even in the high-resolution simulation.