| Project/Area Number |
11640429
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | University of Tokyo |
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Principal Investigator |
ABE Yutaka University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (90192468)
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| Co-Investigator(Kenkyū-buntansha) |
NUMAGUCHI Atsushi Hokkaido University, Graduate School of Earth Environmental Science, Associate Profess, 大学院・地球環境科学研究科, 助教授 (30237797)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1999: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Mars / Paleoclimate / Water circulation / Inclination of spin axis / General circulation model / land planet / 気候 / 降水 / 自転軸 / 古環境 |
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| Research Abstract |
Many fluvial features on Mars indicate active hydrologic cycle on ancient-Mars. In this study, we investigated a water cycle on an idealized planet by using a general circulation model and applied its results to ancient-Mars. Following results are obtained : 1. Three climate regimes are recognized : A.Frozen regime : when the surface temperature is below the freezing point all the year, the entire surface is covered by ice and the hydrologic cycle is essentially stoped due to very low temperature. B.Upright regime : when the summer temperature exceeds the freezing point and the inclination of the spin axis is smaller than the width of the Hadley cell, low latitude area is dried and no precipitation occurs. C.Oblique regime : when the surface temperature is higher than the freezing point and the inclination of the spin axis is larger than the width of the Hadley cell, precipitation occurs in the low latitude areas during summer and winter. 2. Present Mars is in the upright regime with its inclination 23-24 degrees. Ancient mars, however, could have large inclination as large as 60. Thus, Mars likely experienced transition among different climate regimes. In particular, in the oblique regime, summer temperature gets high, this suggests that the oblique regime coincides with the 'past warm and wet climate' on Mars. 3. Cold and wet Mars is unacceptable because in such a situation the surface is entirely covered by snow and 'snow ball Mars' appears.
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