Controls on Variations in Atmospheric Carbon Dioxide and Nitrous Oxide During the Last 10,000 years

地球的温度在一定程度上是由包括二氧化碳、甲烷和一氧化二氮在内的吸热气体控制的。尽管它们对气候很重要，但对大气中这些气体的直接测量最多只能在过去50年内进行。被困在冰芯中的空气将这些数据追溯到数十万年前，而对冰芯中温室气体的测量在很大程度上支持了我们对与现代气候变化相关的全球化学循环的理解。现有的记录在质量和细节上各不相同。这项拟议的工作填补了过去10,000年来我们对一氧化二氮和二氧化碳知识的空白。来自南极冰芯的新测量将被用来确定海洋和陆地过程的变化在控制这些气体方面发挥了什么作用，这些气体在这段时间的前2000年里减少，然后逐渐增加到现在。这项工作将解决关于早期人类活动是否可能影响大气的重大争议，并为改进陆地-海洋-大气系统的数学模型提供数据，这些模型预测未来的气候变化将如何影响大气和气候的组成。对于一氧化二氮，这项工作将改进现有的浓度记录，并提供全新的、详细的全新世稳定同位素记录。它还将开发一氧化二氮同分异构体的测量，并探索其对了解全新世一氧化二氮预算各方面的作用。其主要目标是确定海洋和/或陆地一氧化二氮排放量是否因全新世气候变化而发生变化。新的全新世二氧化碳同位素记录(稳定碳和氧同位素)将使现有记录的精度提高5倍，并提高时间分辨率。这些数据将被用来评估有关二氧化碳浓度在全新世发生变化的有争议的假设，并提供对碳循环中千年尺度过程的洞察，目前的同位素数据尚未解决这些过程。一名研究生将在期间接受高级培训，学生和首席调查员将针对当地中学生进行外展工作。拟议的工作还将有助于国际和平协会的教学工作以及关于气候和气候变化的公开讲座。结果将通过出版物、数据档案和俄亥俄州立大学冰芯实验室网站传播。还将开发和记录具有广泛实用性的新的分析方法。

The temperature of the earth is controlled, in part, by heat trapping gases that include carbon dioxide, methane, and nitrous oxide. Despite their importance to climate, direct measurements of these gases in the atmosphere are limited to the last 50 years at best. Air trapped in ice cores extends those data back hundreds of millennia, and measurements of greenhouse gases in ice cores underpin much of our understanding of global chemical cycles relevant to modern climate change. Existing records vary in quality and detail. The proposed work fills gaps in our knowledge of nitrous oxide and carbon dioxide over the last 10,000 years. New measurements from an ice core from the South Pole will be used to determine what role changes in ocean and land based processes played in controlling these gases, which decreased during the first 2,000 years of this time period, then gradually increased toward the present. The work will address a major controversy over whether early human activities could have impacted the atmosphere, and provide data to improve mathematical models of the land-ocean-atmosphere system that predict how future climate change will impact the composition of the atmosphere and climate. For nitrous oxide the work will improve on existing concentration records and provide a novel, detailed Holocene stable isotope record. It will also develop measurement of the isotopomers of nitrous oxide and explore their utility for understanding aspects of the Holocene nitrous oxide budget. The primary goal is to determine if marine and/or terrestrial emissions of nitrous oxide change in response to changes in Holocene climate. A new Holocene isotopic record for carbon dioxide (stable carbon and oxygen isotopes), will improve the precision of existing records by a factor 5 and increase the temporal resolution. These data will be used to evaluate controversial hypotheses about why carbon dioxide concentrations changed in the Holocene and provide insight into millennial scale processes in the carbon cycle, which are not resolved by current isotopic data. A graduate student will receive advanced training during and the student and principle investigator will conduct outreach efforts targeted at local middle school students. The proposed work will also contribute to teaching efforts by the PI and to public lectures on climate and climate change. The results will be disseminated through publications, data archive, and the OSU Ice Core Lab web site. New analytical methods of wide utility will also be developed and documented.