Using Oxygen Isotopes to Constrain Ozone Sources and Sinks

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。臭氧在全球和区域大气化学中起着至关重要的作用，并对全球气候产生重大影响，因此了解臭氧源和汇过程至关重要。虽然已经取得了实质性的进展，但在臭氧动力学、长距离运输和平流层交换的重要性方面仍有许多悬而未决的问题。臭氧氧同位素组成的变化为了解这些过程提供了一个窗口，然而，数据非常有限，因为现有的臭氧采样方法用于同位素分析是复杂的，繁琐的，并且不适合常规应用。臭氧同位素组成在实验室确定的压力和温度依赖关系中的不确定性也阻碍了进展。该项目的重点是开发和应用一种确定臭氧分子氧同位素组成的新方法，以及在模拟对流层条件下确定臭氧同位素效应的压力和温度依赖性的实验室实验。对普渡大学校园和美国各地监测站进行为期一年的日/夜臭氧同位素组成测量分析，将提供对流层臭氧同位素组成对观测压力和温度依赖性的新数据。这些数据还将深入了解大气中臭氧氧化反应的动力学同位素效应。实验室研究将减少臭氧同位素组成的理论压力和温度依赖性的不确定性，然后将其与实地数据进行比较。除了开发原位臭氧代用品外，来自实验室实验的数据还提供了对臭氧中氧同位素内部分布的见解，这将进一步加深我们对质量无关同位素效应的理解。除了提高对大气臭氧循环的理解外，该项目还将支持一名早期职业研究者，一群代表性不足的博士生，并将继续发展大学研究人员与州政府机构之间的关系。本科生也将成为研究团队的一部分。一个自愿臭氧取样组成部分将把社区参与纳入该项目。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Ozone plays a critical role in global and regional atmospheric chemistry and has a significant impact on global climate, making it vital to understand ozone source and sink processes. Although substantial progress has been made, there are many open questions regarding ozone dynamics, long-rage transport, and the importance of stratospheric exchange. Variation in the oxygen isotope composition of ozone provides a window into these processes, however, data are very limited because existing methods for sampling ozone for isotopic analysis are complex, cumbersome, and impractical for routine application. Uncertainties in laboratory-determined pressure and temperature dependencies of ozone isotopic composition of ozone also hinder progress. The thrusts of this project are the development and application of a new methodology for determining the oxygen isotopic composition of ozone molecules, and laboratory experiments to determine the pressure and temperatures dependencies of ozone isotope effects under simulated tropospheric conditions. Analysis of daily/nightly ozone isotope composition measurements on the Purdue University campus and in a network of stations across the U.S. for a one-year period will provide new data on the observed pressure and temperature dependence of ozone isotope composition in the troposphere. These data will also give insight into the kinetic isotope effects of ozone oxidation reactions in the atmosphere. The laboratory studies will reduce uncertainties in the theoretical pressure and temperature dependence of ozone isotopic composition, which will then be compared with the field data. In addition to developing an in situ ozone proxy, the data from the laboratory experiments provide insights into the internal distribution of oxygen isotopes in ozone, which will further our understanding of mass independent isotope effects. In addition to improving the understanding of atmospheric ozone cycling, the project will support an early-career investigator, an under-represented group doctoral student, and will continue development of relationships between university researchers and state government agencies. Undergraduate students will also be part of the research team. A volunteer ozone sampling component will incorporate community participation into the project.