| Project/Area Number |
06453010
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
地球化学
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| Research Institution | Hokkaido Tokai University |
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Principal Investigator |
UEMATSU Mitsuo SCH.ENG., HOKKAIDO TOKAI UNIV., PROFESSOR, 工学部, 教授 (60203478)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Yoshihisa SCH.OCEAN., TOKAI UNIV., ASSOC.PROFESSOR, 海洋学部, 助教授 (00152752)
MINAMI Hideki SCH.ENG., HOKKAIDO TOKAI UNIV., ASSISTANT, 工学部, 助手 (60254710)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1995: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Atmospheric deposition / Atmospheric aerosol / Marine sediments / Suspended particles / Nitrate particles / Natural radio nuclides / X ray micro-analysis / Pacific ocean / 大気下降物 / 大気エアロソル / 懸濁物粒子 |
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| Research Abstract |
Eastern Asia contains many large pollution sources whose emissions could be transported over large areas of the North Pacific. In order to characterized this transport we have collected a series of weekly aerosol samples and total deposition samples from Sapporo and other sites in Japan since 1990. Marine aerosol samples were also collected on a daily basis using the board of research vessels in the Pacific. The samples were analyzed for non-sea-salt (nss) sulfate, nitrate, and beryllium-7 which is a natural radionuclide (53.3 day half-life) produced by cosmic rays in the upper atmosphere.
A certain correlation among the atmospheric concentrations of the three species is found in the western North Pacific region. This relation does not imply that the sources of the nss sulfate and nitrate are the stratosphere, but it does suggest that anthropogenic nss sulfate and nitrate are brought down from the free troposphere to the marine boundary layr like the Asian dust particles.
Compared with the deposition flux of atmospheric nitrogen of the 40-200 mumol per square meter per day over the Japan islands, the estimated flux of atmospheric nitrogen of 10-30 mumol per square meter per day in the North Pacific is rather small. However, sporadic events coupled with the long-range transport of the nitrogen species from the continents could have a significant impact on marine biological activities.
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