Collaborative Research: Reconstruction of Carbon Monoxide in the Pre-Industrial Arctic Atmosphere from Ice Cores at Summit, Greenland

拟议工作的主要目标是提供工业化前北极大气中一氧化碳（CO）浓度和稳定同位素组成的第一个可靠记录，这也将代表北半球的大部分地区。一氧化碳浓度是任何完整的现代或过去大气数据集的关键组成部分，因为一氧化碳是低层大气中羟基自由基的最大单一汇，在全球大气化学中起着关键作用。一氧化碳浓度与稳定同位素的结合也是大规模生物质燃烧变化的有力示踪剂。工业化前北半球的一氧化碳浓度（在那里，人类活动的影响是最强烈的）的特征不明确，之前的测量是在20世纪90年代使用一种较旧的技术，仅对一个冰芯的少数样品进行的。目前还没有北半球冰芯的一氧化碳同位素测量结果。研究人员建议在格陵兰岛的Summit附近使用Blue ice Drill （BID）收集一个新的大直径冰芯，提供80到170米深度的冰（空气年龄约为公元1960年至1600年）。对一氧化碳浓度的连续测量将提供整个冰芯的高分辨率记录，并确定一氧化碳保存完好的冰层。然后，对一氧化碳浓度和同位素组成的高精度离散分析将以这些层中的冰为目标。还将进行微量化学的连续分析和微量有机物的离散分析，以确定冰芯年代学，并提高对冰中原位一氧化碳产生机制的认识。一氧化碳浓度和同位素组成的大气历史将使用铁冰气体输运和逆模式的组合来推导，并将使用气候化学模式来研究对工业化前一氧化碳收支的影响。提出的方法通过仔细选择地点和应用新的冰钻和分析技术，最大限度地提高了获得可靠的一氧化碳浓度和同位素组成历史的机会。这项研究的结果将通过NSIDC和NOAA的古气候学数据中心向科学界和公众提供。这项工作将有助于培养两名研究生和两名本科生，支持一名早期职业研究者，并在研究者之间建立几项新的合作。研究人员在科学推广方面有着悠久的历史，并致力于通过媒体采访、参与教育电影以及向学校和公众介绍他们的研究等形式进行科学推广，并将继续这些活动，作为拟议工作的一部分。

The main goal of the proposed work is to provide the first reliable record of pre-industrial carbon monoxide (CO) concentration and stable isotope composition in the Arctic atmosphere, which would also be representative of a large part of the Northern Hemisphere. Carbon monoxide concentrations are a crucial component of any complete modern or past atmospheric data set because CO plays a key role in global atmospheric chemistry by being the largest single sink of hydroxyl radicals in the lower atmosphere. Carbon monoxide concentration in combination with stable isotopes is also a powerful tracer for large-scale biomass burning variations. Pre-industrial carbon monoxide concentration in the northern hemisphere (where anthropogenic impacts have been by far the strongest) is poorly characterized, with prior measurements made using an older technique in the 1990s on only a few samples from one ice core. No published carbon monoxide isotope measurements from northern hemisphere ice cores are currently available. The investigators propose to collect a new large diameter ice core near Summit, Greenland using the Blue Ice Drill (BID), providing ice from 80 to 170 meters depth (air age from about 1960 to about 1600 AD). Continuous measurements of carbon monoxide concentration would provide a high-resolution record over the entire ice core and identify ice layers where carbon monoxide is well preserved. High-precision discrete analyses of carbon monoxide concentration and isotopic composition would then target ice from these layers. Continuous analyses of trace chemistry and discrete analyses of trace organics would also be conducted to establish the ice core chronology and improve understanding of mechanisms of in situ carbon monoxide production in ice. Atmospheric histories for carbon monoxide concentration and isotopic composition would be derived using a combination of firn-ice gas transport and inverse models, and the implications for pre-industrial carbon monoxide budget would be investigated with the use of a climate-chemistry model. The proposed approach maximizes the chance of obtaining a reliable history of carbon monoxide concentration and isotopic composition through careful site selection and the application of novel ice drilling and analytical techniques. Results from the study will be made available to the scientific community and the general public through the NSIDC and NOAA Paleoclimatology data centers. The work will contribute to the training of two graduate and 2 undergraduate students, support an early career investigator, and establish several new collaborations among the investigators. The investigators have a strong history of and commitment to scientific outreach in the forms of media interviews, participation in educational films, as well as speaking to schools and the public about their research, and will continue these activities as part of the proposed work.