| Project/Area Number |
18F18316
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| Research Category |
Grant-in-Aid for JSPS Fellows
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| Allocation Type | Single-year Grants |
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| Section | 外国 |
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| Review Section |
Basic Section 17010:Space and planetary sciences-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
今村 剛 東京大学, 大学院新領域創成科学研究科, 教授 (40311170)
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| Co-Investigator(Kenkyū-buntansha) |
KOPPARLA PUSHKAR 東京大学, 新領域創成科学研究科, 外国人特別研究員
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| Project Period (FY) |
2018-10-12 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2019: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2018: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | Venus / climate / variability / atmospheric oscillations / Akatsuki data analysis |
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| Outline of Annual Research Achievements |
a. Intra-Annual Albedo Variability
I studied how changing albedo patterns on Venus are related to the dynamics and chemistry of the atmosphere. I used Venus dayside images from Akatsuki's UV Imager. Each dataset was subjected to a principal component analysis to find the most important modes of variability. The spatial patterns and the timescales of some of these modes correspond to known physical processes in the atmosphere of Venus such as the 4-day Kelvin wave, 5-day Rossby waves, and the overturning circulation, while some others defy a simple explanation. I have thus been able to breakdown the albedo variability into known and unknown dynamics and estimated what fraction of variability can be attributed to each dynamical mode.
b. Decadal Trace Gas Variability
Sulfur dioxide abundances at the cloud-top of Venus have been observed to oscillate on interannual to decadal timescales but the causes are unknown. I am proposing a new conceptual model to explain this occurrence. The water abundance at the base of the clouds, has a strong influence on the cloud-base heating and cloud level convection. The cloud level convective mixing in turn determines the gradient of water abundance in the atmosphere, and thereby the cloud-base water abundance. Thus, the convection and water abundance form a coupled system which oscillates on interannual to decadal timescales, which can explain the timescale of variability in the transport of sulfur dioxide to the cloud tops. This model will represent a fundamental advance of our understanding of long-term atmospheric variability on Venus.
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| Research Progress Status |
令和元年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和元年度が最終年度であるため、記入しない。
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