Organic geochemistry of polar ice and snow

用毛细管气相色谱和气相色谱/质谱仪分析了格陵兰和南极冰芯中的脂肪酸、二元酸、UCM烃、多环芳烃(PAH)。格陵兰冰芯显示，海洋来源的脂肪酸(C&lt；12&gt；-C&lt；18&gt；)的浓度在16世纪到19世纪几乎不变，在1930-1950年间增加，在70年代减少，然后在80年代再次增加。它们在1900年代的变化与北极气温的变化是一致的。这项研究表明，冰芯记录了海洋向空中排放的过去信息，海洋衍生脂肪酸的排放应取决于海冰的进退以及北极地区低压系统的变化。我们还发现，杜鹃酸(C9二酸)与不饱和脂肪酸的浓度比在20世纪40年代有一个较大的峰值。由于前者是后者特有的光氧化产物，这表明该时期大气氧化能力有所增强。南极冰芯显示出多环芳烃和UCM等人为有机成分的存在，其浓度在1900年代后有所增加。这表明南极洲上空输送的有机污染物已经储存在南极冰层中。杜鹃酸/不饱和脂肪酸比值在1970年后有较大幅度的增加，表明南极地区平流层光氧化能力增强，这可能是平流层臭氧层破坏的结果。极地冰芯的有机地球化学研究为恢复极地地区过去的大气条件提供了一条重要的途径。

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.