Methyl Chloride, Methyl Bromide, and Carbonyl Sulfide in Deep Antarctic Ice Cores

Saltzman/0636953该奖项支持一个测量从南极冰芯中提取的空气中的甲基氯、甲基溴和羰基硫化物的项目。之前在冰雪空气和浅冰芯中的测量表明，冰档案中包含了这些气体的古大气信号。这项研究的目标是将这些记录延伸到整个全新世和最后一次冰期，以检查这些痕量气体在更长时间尺度和更广泛的气候条件下的行为。这些研究是探索性的，将评估这些痕量气体的稳定性和它们可能受到现场过程影响的程度。该项目将对Siple Dome、Taylor Dome、Byrd和Vostok冰芯的存档冰芯样本进行采样和分析。冰芯样品将通过干法提取，用气相色谱/质谱仪进行分析，并进行同位素稀释。冰芯测量将产生有关大气中这些微量气体的自然可变性范围的新信息。该项目的学术价值在于，这项工作将为评估人类活动对生物地球化学循环的影响提供更好的基础，并对控制大气成分的生物地球化学过程的气候敏感性提供新的见解。该项目的更广泛影响是，人们对了解人类活动如何影响大气以及未来气候变化可能如何改变大气化学有着强烈的社会兴趣。这项研究的结果将有助于制定用于未来平流层臭氧和气候变化预测的情景。在人类发展方面，该项目将支持地球系统科学研究生的博士论文，以及极地冰芯化学的本科生研究。该项目还将与国家科学基金会赞助的已建立的数学和科学伙伴计划(FOCUS)合作，为奥兰治县学校系统的高中教师制定地球科学教师培训课程。

Saltzman/0636953This award supports a project to measure methyl chloride, methyl bromide, and carbonyl sulfide in air extracted from Antarctic ice cores. Previous measurements in firn air and shallow ice cores suggest that the ice archive contains paleo-atmospheric signals for these gases. The goal of this study is to extend these records throughout the Holocene and into the last Glacial period to examine the behavior of these trace gases over longer time scales and a wider range of climatic conditions. These studies are exploratory, and both the stability of these trace gases and the extent to which they may be impacted by in situ processes will be assessed. This project will involve sampling and analyzing archived ice core samples from the Siple Dome, Taylor Dome, Byrd, and Vostok ice cores. The ice core samples will be analyzed by dry extraction, with gas chromatography/mass spectrometry with isotope dilution. The ice core measurements will generate new information about the range of natural variability of these trace gases in the atmosphere. The intellectual merit of this project is that this work will provide an improved basis for assessing the impact of anthropogenic activities on biogeochemical cycles, and new insight into the climatic sensitivity of the biogeochemical processes controlling atmospheric composition. The broader impact of this project is that there is a strong societal interest in understanding how man's activities impact the atmosphere, and how atmospheric chemistry may be altered by future climate change. The results of this study will contribute to the development of scenarios used for future projections of stratospheric ozone and climate change. In terms of human development, this project will support the doctoral dissertation of a graduate student in Earth System Science, and undergraduate research on polar ice core chemistry. This project will also contribute to the development of an Earth Sciences teacher training curriculum for high school teachers in the Orange County school system in collaboration with an established, NSF-sponsored Math and Science Partnership program (FOCUS).