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Organic geochemistry of polar ice and snow

极地冰雪的有机地球化学

基本信息

批准号：
09304054
负责人：
KAWAMURA Kimitaka
金额：
$ 24.58万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

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.

格陵兰和南极冰芯的脂肪酸，二羧酸，UCM烃，多环芳烃（PAH）使用毛细管气相色谱和GC/质谱分析。格陵兰冰芯表明，海洋脂肪酸（<12>C-C）<18>浓度在16 - 19世纪基本保持不变，1930-1950年上升，1970年代下降，1980年代又上升。它们在20世纪的变化与北极气温的变化相一致。这项研究表明，冰芯记录了过去的海洋来源的脂肪酸排放的海洋到空气中的信息，应该取决于海冰的进展/退缩，以及在北极地区的低压系统的变化。在20世纪世纪，壬二酸（C_9二酸）与不饱和脂肪酸的浓度比呈上升趋势，并在20世纪40年代出现一个较大的峰值。由于前者是后者的特定光氧化产物，这表明在这一时期大气氧化能力有所增强。南极冰芯表明，存在人为有机成分，如PAH和UCM，其浓度在1900年代后增加。这表明在南极上空输送的有机污染物已经储存在南极冰中。壬二酸/不饱和脂肪酸的比值在1970年后有较大幅度的增加，这表明南极平流层光氧化能力增强，可能是平流层臭氧层破坏的结果。极地冰芯有机地球化学研究为重建极地地区过去的大气条件提供了一种新的途径。