| Project/Area Number |
16K05566
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Research Collaborator |
KASABA YASUMASA
SAGAWA HIDEO
KURODA TAKESHI
AOKI SHOHEI
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2017: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2016: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
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| Keywords | 火星 / 進化 / 水 / 散逸 / 観測 / 循環 / 探査機 / 大気重力波 / 同位体 / 大気進化 / Mars / water / isotopes / spectroscopy / heterodyne / SOFIA / MAVEN / 惑星探査 / 超高層物理学 / 水循環 / 惑星進化 |
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| Outline of Final Research Achievements |
TGO observations first reveal the vertical distribution of the HDO/H2O up to 80 km, which suggest an increase of the abundance of H2O and HDO during the dust storm. Simultaneously, our ground-based observations found a remarkable enhancement of the atmospheric temperature at 80 altitudes during the dust storm. This could cause stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapor to lower altitudes. Our MAVEN result indicates the detection of an extensive layer of warm air at altitudes 70 to 90 km, which has a good agreement with above. The atmospheric composition and wave activity in the upper atmosphere dramatically changes in season. Our study proposes an effective and high-speed mass/energy transportation into the upper atmosphere. The resultant stronger atmospheric circulation could carry the dust and water vapor into the upper atmosphere, which drive direct escape of water to space in a time-scale of weeks or months.
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| Academic Significance and Societal Importance of the Research Achievements |
約40億年前には豊富な液体の水をたたえ、温暖湿潤な気候を有していた火星は、劇的な気候変動を経て、現在のような寒冷で乾燥した惑星となった。火星のこの劇的な進化の過程で、温暖湿潤な環境を維持するための大量の大気と水がどこにどのようにして失われたかは、惑星表層環境の進化の理解にとって大きな謎として残されている。本研究により明らかになりつつある火星大気・水の散逸プロセスの理解は、生命を保持しうる惑星環境を理解する上で重要であり、昨今発見が相次ぐ系外惑星への示唆に富む。
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