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来源贡献的时间变异性，(2)开始调查OH的相应趋势。这项工作的动机是需要更好地了解今天大气中CH4-OH-CO系统相对于过去变化范围的背景化学。OH在很大程度上决定了大多数活性大气物种的化学氧化机制和寿命。同样，CO是大气中最重要的活性痕量气体之一，因为它的反应性和丰度相结合。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浓度、13CO和C18O将在积雪和冰的存档岩心样本中被捕获的空气中进行测量。CO中的Delt17O将作为大尺度OH丰度和时间变异性的替代指标而被测量。已经证明了Delt17O在限制大气OH方面的应用，但需要一种新的分析方法来表征冰芯中的小体积气泡，以将这一记录扩展到过去。首席调查员(PI)将在目前用于测量冰芯CO中13C和18O的系统的基础上，建立一个新的分析系统来测量低体积气泡中CO中的delt17O，以及一个旨在测量更大整体空气样本中CO中delt17O的离线系统。量化OH的可变性对于了解对流层(NOx、CO、CH4、VOCs、SOx、二次气溶胶等)的整体快速光化学至关重要。以及含氢温室气体的寿命。一名博士后科学家和一名研究生将参与并通过该项目接受培训。此外，石溪大学两名计划成为高中教师的本科地质专业学生将接受当地一名高中教师的指导。这些本科生还将通过PI的小组在适当的研究主题上指导高中生。这一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.