Trapped Gases in the Greenland Ice Sheet: CO2 Isotope Ratios & Concentration in the Past Atmosphere

格陵兰冰盖中滞留的气体：二氧化碳同位素比率

• 批准号: 8821995
• 负责人: Alexander Wilson
• 金额: $ 53.21万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-03-01 至 1995-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8821995&HistoricalAwards=false
• 关键词: Trapped; Gases; Greenland; Ice; Sheet

As part of the Greenland Ice Sheet Project, this project will extend the atmospheric CO2 concentration and isotope composition record back through Holocene times. This would be done by measuring the concentration and C13/C12 ratio of carbon dioxide in atmospheric gases trapped in relatively small (250 g) samples of ice from Greenland ice cores. The technique would be to place the sample in a specially designed vacuum system and to sublime the ice onto the surface of a -80 c cold trap. The gas will be released by this procedure. The amount of CO2 sample so obtained would be accurately measured and its C13/C12 ratio determined. The air in the sample would be recovered on molecular sieve. The amount of air, per unit of ice, would record the altitude of the ice sheet at the time of seal-off. The ratio of CO2 to air would be accurately measured (to better than 0.5%) which would record the CO2 concentration of the sample of trapped atmosphere to better than 1ppm. The C13/C12 ratio of atmospheric carbon dioxide during glacial times will also be measured. The change of this ratio during the glacial/post-glacial transition will be an important test of the proposed mechanisms for the large (80 ppm) CO2 concentration change that occurred at that time. Other climate-related questions include a detailed study of the end of the last glacial and the glacial/post-glacial transition, the Younger Dryas event, and the Dansgaard-Oeschger events. These concentration and stable isotope data, combined with radiocarbon dates for CO2, will enable testing of carbon cycle models relating to past and future climate change.

作为格陵兰冰盖项目的一部分，该项目将把大气二氧化碳浓度和同位素组成记录追溯到全新世时期。 这可以通过测量格陵兰冰芯相对较小（250 克）的冰样本中捕获的大气气体中二氧化碳的浓度和 C13/C12 比率来完成。 该技术是将样品放置在专门设计的真空系统中，并将冰升华到 -80 摄氏度的冷阱表面。 此过程将释放气体。 如此获得的 CO2 样品的量将被精确测量并确定其 C13/C12 比率。 样品中的空气将在分子筛上回收。 每单位冰的空气量将记录封锁时冰盖的高度。 精确测量 CO2 与空气的比例（优于 0.5%），记录捕获大气样本中的 CO2 浓度优于 1ppm。 冰河时期大气二氧化碳的 C13/C12 比率也将被测量。 冰期/后冰期过渡期间这一比率的变化将是对当时发生的二氧化碳浓度大变化（80 ppm）的拟议机制的重要检验。 其他与气候相关的问题包括对末次冰期结束和冰期/冰期后过渡、新仙女木事件和丹斯加德-厄施格事件的详细研究。 这些浓度和稳定同位素数据与二氧化碳的放射性碳测年相结合，将能够测试与过去和未来气候变化相关的碳循环模型。