| Project/Area Number |
17201003
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KONDO Yutaka The University of Tokyo, Research Center for Advanced Science and Technology, Professor, 先端科学技術研究センター, 教授 (20110752)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEGAWA Nobuyuki The University of Tokyo, Research Center for Advanced Science and Technology, Associate Professor, 先端科学技術研究センター, 助教授 (00324369)
MIYAZAKI Yuzo The University of Tokyo, Research Center for Advanced Science and Technology, Research Associate, 先端科学技術研究センター, 助手 (60376655)
KOIKE Makoto The University of Tokyo, School of Science, Associate Professor, 大学院理学系研究科, 助教授 (00225343)
駒崎 雄一 東京大学, 先端科学技術研究センター, 科学技術振興特任教員(特任助教授) (80286640)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥51,090,000 (Direct Cost: ¥39,300,000、Indirect Cost: ¥11,790,000)
Fiscal Year 2006: ¥17,810,000 (Direct Cost: ¥13,700,000、Indirect Cost: ¥4,110,000)
Fiscal Year 2005: ¥33,280,000 (Direct Cost: ¥25,600,000、Indirect Cost: ¥7,680,000)
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| Keywords | aerosol / black carbon / mixing state / CCN / cloud / indirect effect / climate changel |
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| Research Abstract |
Cloud condensation nuclei (CCN) activity is determined by aerosol diameter, fraction of water soluble components, and surface tension. We quantified CCN activities as a function of these parameters and related them with cloud formation processes.
A)Controlling factors of CCN activities of aerosol in urban air
We measured chemical composition, mixing states, and CCN activity of aerosol in Tokyo using an aerosol mass spectrometer, black carbon (BC) instruments, and a CCN counter. We found that CCN activity of thickly coated BC is controlled by the chemical composition of water soluble compounds. The CCN activity of thinly coated BC is controlled by the thickness of the coating.
B)Measurements of aerosol-cloud interaction
We conducted aircraft measurements of aerosol and cloud particles inside and outside of clouds located at 1-2 km near Japan in spring. We showed that thickly coated BC particles were taken up into clouds efficiently, consistent with the ground based measurements. This also s
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hows that BC can be a good tracer to quantitatively study aerosol-cloud interaction.
C)Time constant of CCN formation
We showed that CCN activity of aerosol transported from the Asian continent within a few days is controlled mainly by the fraction of water soluble components from the data obtained in Jeju Island, Korea. Decrease in the surface tension of organic aerosol is also estimated to is contribute to the CCN activity. The CCN activity of various types of aerosol was measured also near Beijing. The observed CCN activity is consistent with the understandings obtained in Tokyo and Jeju Is.
D)Calibration of the cloud probe and its aerodynamical characteristics
Light scattering cloud probe was calibrated using standard particles with high precision. We made aerodynamical calculations of airflows around the probe mounted on the aircraft and found high collection efficiency of cloud droplets.
E)We calculated size distribution of cloud droplets predicted from various CCN concentrations using a trajectory model. Sensitivity of CCN-cloud interaction was estimated by the numerical experiments. Less
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