Understanding Recent Changes in the Atmospheric Methane Growth Rate through Analyses of the Isotopic Composition of Methane in a Rare Air Archive

该项目的主要目标是通过以下方式更好地了解大气甲烷（CH4）增长率的最新趋势：(1)利用俄勒冈研究生院（OGI）空气档案样本分析近20年来CH4的同位素组成；(2)根据CH4源和汇的变化解释大气CH4的长期和年际变化。将对最初在俄勒冈州米尔斯角（1978-1998）、南极洲帕尔默站（1991-1997）和阿拉斯加巴罗角（1995-1998）收集的380多个样品进行CH4同位素组成（13C/12C和D/H）分析。由此产生的数据集将提供1988年以前北半球13C/12C的唯一可用时间序列记录，并且在任何情况下都是唯一的月分辨率记录。同样重要的是，D/H时间序列将是1996年以前的唯一记录。结果将与更现代的记录合并，形成一个30年的复合记录，并根据这段时间内CH4的生物源、化石源和热源的变化来解释CH4浓度和同位素组成变化的结果。波特兰州立大学本科生和研究生通过该项目在前沿研究领域提供的实践研究机会将促进他们的发展，并为下一代地球科学研究奠定基础。与波特兰科学与工程学徒计划建立伙伴关系，将在夏季启动并培养与当地高中生的指导关系，并提供框架，在有前途的年轻学生投身大学重点领域之前，向他们传达科学探索的兴奋和挑战。

The primary objective of this project is to better understand recent trends in the growth rate of atmospheric methane (CH4) through: (1) analysis of the isotopic composition of CH4 over two decades using samples from the Oregon Graduate Institute (OGI) air archive and (2) the interpretation of long-term and interannual variations in atmospheric CH4 in terms of changing CH4 sources and sinks. More than 380 samples originally collected at Cape Meares, Oregon (1978-1998), Palmer Station, Antarctica (1991-1997), and Point Barrow, Alaska (1995-1998) will be analyzed for their CH4 isotopic composition (13C/12C and D/H). The resulting dataset will provide the only northern hemisphere time series record of 13C/12C available prior to 1988, and the only one at monthly resolution in any case. Equally important, the D/H time series will be the only record available prior to 1996. Results will be merged with more modern records creating a 30 year composite record and interpret the results of the changing concentration and isotopic composition of CH4 in terms of changing biogenic, fossil, and pyrogenic sources of CH4 over this time period.The hands-on research opportunities for Portland State University undergraduate and graduate students provided through this project in an area of cutting edge research will enhance their development and build a foundation for the next generation of Earth science research. Building a partnership with the Portland Apprenticeships in Science and Engineering Program will initiate and foster a relationship of mentoring with local high school students during summers and provide the framework for conveying the excitement and challenges of science exploration to promising young students before they commit to fields of focus in college.