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北极大气中工业化前一氧化碳浓度和稳定同位素组成的第一个可靠记录，这也将代表北方的大部分地区。一氧化碳浓度是任何完整的现代或过去的大气数据集的关键组成部分，因为CO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结合也是大规模生物质燃烧变化的有力示踪剂。北方半球（人类活动的影响最为强烈）工业化前的一氧化碳浓度特征很不明确，先前的测量是在1990年代使用一种较老的技术，只对一个冰芯的几个样本进行的。目前还没有发表的北方冰芯一氧化碳同位素测量结果。研究人员建议使用Blue Ice Drill（BID）在格陵兰岛Summit附近收集一个新的大直径冰芯，提供80至170米深的冰（空气年龄约为1960至1600 AD）。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良好的冰层。对一氧化碳浓度和同位素组成的高精度离散分析将针对这些层中的冰。还将进行痕量化学的连续分析和痕量有机物的离散分析，以建立冰芯年表，并提高对冰中原位产生一氧化碳的机制的认识。大气中一氧化碳浓度和同位素组成的历史将使用一个组合的雪冰气体传输和逆模型，并与使用气候化学模型的一氧化碳预算的影响进行调查。所提出的方法最大限度地获得一个可靠的一氧化碳浓度和同位素组成的历史，通过仔细的选址和应用新的冰钻和分析技术的机会。研究结果将通过NSIDC和NOAA古气候学数据中心提供给科学界和公众。这项工作将有助于培训两名研究生和两名本科生，支持一名早期职业调查员，并在调查员之间建立几个新的合作。研究人员有很强的历史和承诺，以媒体采访的形式进行科学宣传，参与教育电影，以及向学校和公众介绍他们的研究，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.