2020 Fiscal Year Final Research Report

A study of stochastic behavior of atmospheric gravity waves in the Antarctic by advanced balloon observations

Research Project

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Project/Area Number	18H01276
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 17020:Atmospheric and hydrospheric sciences-related
Research Institution	The University of Tokyo
Principal Investigator	Sato Kaoru 東京大学, 大学院理学系研究科(理学部), 教授 (90251496)
Co-Investigator(Kenkyū-buntansha)	村田功東北大学, 環境科学研究科, 准教授 (00291245) 冨川喜弘国立極地研究所, 研究教育系, 准教授 (20435499) 齋藤芳隆国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 准教授 (50300702)
Project Period (FY)	2018-04-01 – 2021-03-31
Keywords	大気重力波 / スーパープレッシャー気球 / 大型大気レーダー
Outline of Final Research Achievements	Momentum transport by atmospheric gravity waves (GWs) is one of the main uncertainties in the current climate models, especially in the Antarctic region where uncertainties are large. In order to obtain a three-dimensional picture of the momentum transport due to GWs, we proposed a super-pressure (SP) balloon observation of GWs over the Antarctic and developed its balloon and onboard instrument. A SP balloon with designated pressure resistance and gas permeability was successfully developed by covering the double-membrane SP balloon with a vectran net. In addition, an onboard instrument which measures horizontal wind velocity, air temperature, and pressure every 30 sec were manufactured. It has a weight less than 3 kg and is classified as a light balloon according to the regulations of the International Civil Aviation Organization. The first SP balloon observation in the Antarctic region will be performed by the 63rd Japanese Antarctic Research Expedition around January 2022.
Free Research Field	大気力学・中層大気科学
Academic Significance and Societal Importance of the Research Achievements	南半球高緯度域は重力波活動の高い領域であることが衛星観測や高解像度大気大循環モデル研究により指摘されており、重力波の観測強化が求められている。重力波の持つ幅広い時空間スケールを全て網羅し、かつその運動量輸送を測定できる観測は、大型大気レーダー観測とSP気球観測のみである。本研究によりSP気球観測が実現すれば、南極大型大気レーダー（PANSY）と組み合わせることで、重力波の観測情報が特に不足している南極域において重力波による運動量輸送の3次元的描像の理解が深まる。これは学術的意義のみならず、気候モデルの不確実性を低減し、将来予測の精度を向上させることにつながるため、社会的にも大きな意義がある。