Generating an Isotopic Record of Atmospheric Methane and Nitrous Oxide Over the Last Century from South Pole Firn Air

从南极冷空气生成上个世纪大气甲烷和一氧化二氮的同位素记录

• 批准号: 0125981
• 负责人: Todd Sowers
• 金额: $ 13.02万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0125981&HistoricalAwards=false
• 关键词: Generating; Isotopic; Record; Atmospheric; Methane

0125981SowersThis award supports a project to construct an isotopic record of atmospheric methane and nitrous oxide over the last century from South Pole firn air. Over the last 150 years, atmospheric methane and nitrous oxide concentrations have risen in response to increased emissions from various anthropogenic activities. As this trend is liable to continue in the foreseeable future, it is important to understand the biogeochemical processes that contribute to the emissions of these two greenhouse gases. In this context, records of the variations in the atmospheric loading of trace gases found in ice cores and interstitial spaces in the snow near the surface of the ice sheet (firn air) provide fundamental boundary conditions for reconstructing historical emission records. One way to improve our understanding of the cycling of bioactive trace gases and their emission records is to use stable isotope tracers, which have been recorded in the ice cores and firn air. This project will develop records of carbon-13 and deuterium isotope ratios of methane, as well as the nitrogen-15, oxygen-18 and the isotopomer composition of nitrous oxide trapped in firn air samples collected in January 2001 at the South Pole. These measurements will allow isotopic records of these atmospheric gases to be reconstructed throughout the 20th century. Such records will help to establish the relative contribution of individual sources with a higher degree of confidence than is currently available.

0125981 Sowers该奖项支持一个项目，以建立一个同位素记录的大气甲烷和一氧化二氮在过去世纪从南极雪空气。 在过去的150年里，由于各种人类活动造成的排放量增加，大气中甲烷和一氧化二氮的浓度也随之上升。 由于这一趋势在可预见的未来可能会继续下去，因此必须了解导致这两种温室气体排放的地球化学过程。 在这种情况下，记录的微量气体在大气中的负载变化，发现在冰芯和间隙空间的雪表面附近的冰盖（积雪空气）重建历史排放记录提供了基本的边界条件。 提高我们对生物活性痕量气体循环及其排放记录的理解的一种方法是使用稳定同位素示踪剂，这些示踪剂已在冰芯和积雪空气中记录。 该项目将记录2001年1月在南极采集的积雪空气样品中甲烷的碳-13和氘同位素比率，以及氮-15、氧-18和一氧化二氮的同位素组成。 这些测量将使这些大气气体的同位素记录在整个世纪得以重建。 这些记录将有助于以比目前更高的可信度确定个别来源的相对贡献。