2012 Fiscal Year Final Research Report
Understanding of the periodicity of the past solar activity by radiocarbon measurements and the relation to the global environment
| Project/Area Number |
22340144
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | Nagoya University |
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Principal Investigator |
MASUDA Kimiaki 名古屋大学, 太陽地球環境研究所, 准教授 (40173744)
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| Research Collaborator |
NAGAYA Kentaro 名古屋大学, 太陽地球環境研究所, 大学院生
MIYAKE Fusa 名古屋大学, 太陽地球環境研究所, 大学院生
NAKAMURA Toshio 名古屋大学, 年代測定総合研究センター, 教授
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| Project Period (FY) |
2010 – 2012
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| Keywords | 太陽地球システム / 宇宙天気 / 太陽物理学 / 地球変動予測 / 宇宙線 / 放射性炭素 / 加速器質量分析計 |
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| Research Abstract |
We have measured the radiocarbon concentration in tree rings from the past 3,000 years and discussed the variation of cosmic-ray intensity and solar activity in the past. We found the increase of theSchwabe cycle lengths from the modern value of 11 years to 13-16 years during grand solar minima, which are characteristic periods of solar activity change. We also discovered the rapid increase of radiocarbon concentration at AD775 and AD993. These events indicate that extremely large solar flares occurred at the solar surface in these yearsand a lot of solar high-energy particles arrived at the global environment. These results largely contribute to solve the dynamo mechanism of solar activity and the understanding of its influence to the Earth.
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