The Chemistry and Sources of Carbon Monoxide in Present and Past Atmospheres

这项研究工作将(1)量化过去几千年来主要CO源贡献的时间变化，(2)开始研究OH的相应趋势。这项工作的动机是需要更好地了解当今大气中CH4-OH-CO系统相对于过去变率范围的背景化学。OH在很大程度上决定了化学氧化机制和大多数活性大气物质的寿命。同样，CO是大气中最重要的反应性微量气体之一，因为它的反应性和丰度都很高。由于CO和CH4之间的密切联系，这些研究也将有助于解决过去驱动CH4浓度变化的机制。CO、13CO和C18O的浓度将在存档的冰芯样品中测量。CO中的Delt17O将作为大尺度OH丰度和时间变异性的代表进行测量。delt17O用于约束大气OH的应用已经得到证实，但需要一种新的分析方法，能够表征冰芯中小体积气泡的特征，以便将记录延伸到过去。在目前用于测量冰芯中CO中的13C和18O的系统和设计用于测量更大整体空气样本中CO中的delt17O的离线系统的基础上，首席研究员（PI）将构建一个新的分析系统来测量小体积气泡中CO中的delt17O。量化OH变异性对于理解对流层（NOx、CO、CH4、VOCs、SOx、次生气溶胶等）的整体快速光化学以及含h温室气体的寿命至关重要。1名博士后科学家和1名研究生将参与并通过该项目接受培训。此外，石溪分校两名计划成为高中教师的地质学本科生将由当地一名高中教师指导。这些本科生还将通过PI小组指导高中生进行适当的研究课题。该试点计划将由所有参与的学生和教师/顾问进行评估，如果成功，将实施更广泛的计划。

This research effort will (1) quantify temporal variability in contributions of major sources of CO over the past several thousand years and (2) begin to investigate the corresponding trends in OH. The work is motivated by the need to better understand the background chemistry of the CH4-OH-CO system in today's atmosphere relative to the range in variability over the past. OH largely determines both the chemical oxidation mechanisms and the lifetimes of most reactive atmospheric species. Similarly, CO is one of the most important reactive trace gases in the atmosphere because of its combined reactivity and abundance. Because of the close link between CO and CH4, these studies will also help to resolve mechanisms that drove CH4 concentration changes in the past. CO concentration, 13CO, and C18O will be measured in air trapped in archived core samples of firn and ice. Delt17O in CO will be measured as a proxy of large-scale OH abundance and temporal variability. The application of delt17O to constrain atmospheric OH has been demonstrated but a new analytical approach with the capability to characterize low-volume air bubbles in ice cores is required to extend the record to the past. The Principal Investigator (PI) will construct a new analytical system to measure delt17O in CO in low-volume air bubbled based on the system currently used to measure 13C and 18O in CO from ice cores and an offline system designed to measure of delt17O in CO from larger whole air samples.Quantifying OH variability is critical to understanding the overall fast photochemistry of the troposphere (NOx, CO, CH4, VOCs, SOx, secondary aerosols, etc.) and the lifetimes of H-containing greenhouse gases. One postdoctoral scientist and one graduate student will participate in and be trained through this project. In addition, two undergraduate geology majors at Stony Brook who plan to become high school teachers will be mentored by a local high school teacher. These undergraduate students will also mentor high school students in appropriate research topics through the PI's group. This pilot program will be evaluated by all students and teachers/advisors involved and, if successful, a broader program will be implemented.