名古屋大学素粒子宇宙起源研究所の中澤知洋 准教授を代表とする宇宙地球環境研究所との融合研究戦略課題「アルベドの融合科学〜国際宇宙ステーションから探るアルベドX線・ガンマ線・中性子線〜」に関係して、X線天文衛星を用いて、2022年のトンガ噴火による超高層大気変化を捉えた研究成果が、以下のとおり、Geophysical Research Lettersに論文掲載されました。
本研究は、名古屋大学素粒子宇宙起源研究所と宇宙地球環境研究所の融合研究戦略課題を契機としてスタートしたもので、論文の筆頭著者は、埼玉大学理工学研究科の勝田 哲 准教授です。論文のタイトルは「X-Raying Neutral Density Disturbances in the Mesosphere and Lower Thermosphere Induced by the 2022 Hunga-Tonga Volcano Eruption-Explosion」です。
論文はこちらから閲覧できます。
Katsuda, S., H. Shinagawa, H. Fujiwara, H. Jin, Y. Miyoshi, Y. Miyoshi, Y. Motizuki, M. Nakajima, K. Nakazawa, K. K. Nobukawa, Y. Otsuka, A. Shinbori, T. Sori, C. Tao, M. S. Tashio, Y. Wada, and T. Yamawaki : X-raying neutral density disturbances in the mesosphere and lower thermosphere induced by the 2022 Hunga-Tonga Volcanote erupition-explosion, Geophys. Res. Lett., 51, doi:10.1029/2024GL12025, 2024.
Abstract
We present X-ray observations of the upper atmospheric density disturbance caused by the explosive eruption of the Hunga Tonga-Hunga Ha'apai (HTHH) volcano on 15 January 2022. From 14 January to 16 January, the Chinese X-ray astronomy satellite, Insight-HXMT, was observing the supernova remnant Cassiopeia A. The X-ray data obtained during Earth's atmospheric occultations allowed us to measure neutral densities in the altitude range of
-90 – 150 km. The density profiles above 110 km altitude obtained before the major eruption are in reasonable agreement with expectations by both GAIA and NRLMSIS 2.0 models. In contrast, after the HTHH eruption, a severe density depletion was found up to 1,000 km away from the epicenter, and a relatively weak depletion extending up to - 7,000 km for over 8 hr after the eruption. In addition, density profiles showed wavy structures with a typical length scale of either -20 km (vertical) or -1,000 km (horizontal). This may be caused by Lamb waves or gravity waves triggered by the volcanic eruption.