| Project/Area Number |
09304054
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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 |
地球化学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KAWAMURA Kimitaka Hokkaido Univ., Inst.of Low Temp.Sci., Prof., 低温科学研究所, 教授 (70201449)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Okitsugu National Inst.of Polar Res., Prof., 教授 (60111861)
NAKATSUKA Takeshi Hokkaido Univ., Inst.of Low Temp.Sci., Asso.Prof., 低温科学研究所, 助教授 (60242880)
大河内 直彦 北海道大学, 低温科学研究所, 助手 (00281832)
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| Project Period (FY) |
1997 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥38,400,000 (Direct Cost: ¥38,400,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1997: ¥34,800,000 (Direct Cost: ¥34,800,000)
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| Keywords | Ice core / Greenland / Antarctic / Fatty acids / Dicarboxylic acids / PAH / Stratospheric ozone destruction / Tropospheric oxidizing capability / 有機物 / 炭化水素 / 大気輸送 / 大気環境変化 / 微量分析 / 脂質 / オゾンホール / 海洋生物 / 地球温暖化 / アイスコア / グリーンランド / ジカルボン酸 / アゼライン酸 / 大気海洋相互作用 / 温暖化 / 陸上植物 / 湿暖期 |
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| Research Abstract |
Greenland and Antarctica ice cores have been analyzed for fatty acids, dicarboxylic acids, UCM hydrocarbons, polycyclic aromatic hydrocarbons (PAH) using a capillary gas chromatography and GC/mass spectrometer. The Greenland ice core showed that the concentrations of fatty acids of marine origin (C_<12>-C_<18>) were almost constant in 1500s to 1800s, increased in 1930-1950 years, decreased in 1970s, then again increased in 1980s. Their variations in 1900s were found to be consistent with the variations of the Arctic air temperature. This study demonstrated that the ice core recorded the past information on the sea to air emission of marine-derived fatty acids that should depend on the progress/retreat of sea ice as well as variations of low pressure systems in the arctic regions. We also found an increase in the concentration ratios of azelaic acid (C_9 diacid) to unsaturated fatty acids in the twentieth century with a large peak in 1940s. Because the former acid is the specific photo-oxidation product of the latter, this suggests that the atmospheric oxidizing capability has increased in that period.
The Antarctic ice core showed that the presence of anthropogenic organic components such as PAH and UCM, whose concentrations increased after 1900s. This indicates that organic pollutants transported over the Antarctica have been stored in the Antarctic ice. The azelaic acid/unsaturated fatty acid ratios showed a large increase after 1970 AD.Such an increase suggests that the stratospheric photo-oxidizing capability was enhanced over the Antarctica, probably as a result of the destruction of stratospheric ozone layer.
The organic geochemical study of polar ice cores demonstrated a noble approach for the reconstruction of past atmospheric conditions in the polar regions.
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