Using the Isotopes of Carbon Monoxide (CO) as Tracers of Current Global Hydroxyl (OH) Trends and Preindustrial CO Sources

利用一氧化碳（CO）作为相对保守的示踪剂，本项目研究了全球范围内重要的大气氧化剂羟基自由基（OH）的时空变化。由于CO与OH的反应是大气CO最重要的损失过程，因此这两个物种密切耦合。该项目的第一个要素包括在每个半球的热带清洁空气采样点监测同位素标记的14CO丰度，并通过与其他小组合作，在每个半球的中纬度和高纬度地点进行类似测量。利用先进的三维大气环流模型模拟对数据进行分析和解释，目的是提高我们对大气氧化能力的理解。该研究的第二个要素需要使用碳和氧的稳定同位素比率以及从铁芯和冰芯中提取的空气样本中测量的CO混合比率，以确定工业化前时代生物质燃烧产生的南半球CO源强度。通过在我们对大气氧化能力的理解方面取得重大进展，以及在国际合作环境中对年轻大气科学家的教育，解决了更广泛的影响。这项研究的数据将对大气CO预算提供强有力的约束，并提供关于全球OH行为的新信息——每一个都对气候变化和全球政策有影响。该项目教育计划包括研究生和本科生的研究机会，包括通过科学与工程领域的女性（WISE）项目为女性提供的研究机会。

Using carbon monoxide (CO) as a relatively conserved tracer this project investigates temporal and spatial variations on a global scale of an important atmospheric oxidant, the hydroxyl radical (OH). These two species are closely coupled since the reaction of CO with OH is the most important loss process for atmospheric CO. The first element of the project involves monitoring isotopically labeled 14CO abundance at a tropical, clean air sampling site in each hemisphere, in conjunction with similar measurements at mid- and high-latitude sites in each hemisphere through collaborations with other groups, with data analyzed and interpreted in terms of advanced 3-D general circulation model simulations with the objective of improving our understanding of the oxidative capacity of the atmosphere. The second element of the study entails using stable isotope ratios of carbon and oxygen and mixing ratios of CO measured in air samples extracted from firn and ice cores to determine the southern hemisphere CO source strength from biomass burning in pre-industrial times. Broader impacts are addressed by providing a significant advance in our understanding of the oxidizing capacity of the atmosphere, and the education of young atmospheric scientists in an environment of international collaboration. Data from this study will provide powerful constraints on the atmospheric CO budget, and provide new information on global OH behavior - each having implications for climate change and global policy. The project education plan includes research opportunities for graduate students and undergraduates - including women through the Women in Science and Engineering (WISE) program.