Collaborative Research: Automated continuous measurement of CFC and SF6 saturations in surface waters

合作研究：自动连续测量地表水中的 CFC 和 SF6 饱和度

• 批准号: 1035515
• 负责人: David Ho
• 金额: $ 45.75万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1035515&HistoricalAwards=false
• 关键词: Collaborative; Research; Automated; continuous; measurement

Knowing the age of water masses is important in estimating anthropogenic CO2 uptake by the ocean. The age of a water mass can be characterized by a probability distribution function, or transit time distribution (TTD), and transient tracers such as CFCs and SF6 are used to constrain the TTD. However, one of the largest sources of uncertainty in constraining TTDs is lack of knowledge about surface tracer saturations. Knowledge of the surface saturation is also needed to investigate ocean mixing and circulation using tracers in ocean circulation models and to calculate water mass formation rates from tracer inventories. To reduce the uncertainty in CFC and SF6 saturations, researchers at the University of Hawaii at Manoa and at the Lamont-Dougherty Earth Observatory of Columbia University will construct an automated analysis system for continuous measurements of CFCs and SF6 from the surface ocean and the atmosphere. Even though the measurement of CFCs and SF6 in seawater is fairly routine, having an automated system operated by one person will permit saturation data to be acquired from a variety of ships with little manpower. The new analysis system will be deployed on CLIVAR/Repeat Hydrography cruises in a subpolar/polar region (e.g., S4P) and a subtropical region (e.g., A20/A22/A16), with the eventual goal of deploying the system on future CLIVAR/Repeat Hydrography cruises, and on ships of opportunity to regions during winter when deep water formation occurs and very few measurements have been made. By documenting variations in tracer saturation levels and environmental variables (e.g., temperature, salinity, wind speeds, mixed layer depth), the research team expects to provide the community with much needed measurements to constrain tracer-based estimates of anthropogenic CO2 uptake, provide better boundary conditions for model calculations using CFCs and SF6, and begin to gain some insights into processes controlling the saturations of these gases in the surface ocean. Broader Impacts The study of water mass ages using transient tracers is an important aspect of the overall study of the ocean circulation and of the ability of the ocean to take up the large amounts of CO2 that are being released to the environment by the burning of fossil fuels. The uptake of CO2 by the ocean, in turn, will moderate changes in the Earth's climate due to human perturbations. Better knowledge of SF6 and CFC saturations will reduce errors in determining water mass formation rates from CFC and SF6 inventories, reduce errors in circulation time scales determined from SF6 and CFC data, provide tighter constraints on circulation models that utilize these tracers, and reduce errors in determination of oceanic uptake of anthropogenic CO2 based on CFC and SF6 water mass ages. As an educational component, undergraduate students will be hired to work during the second and third summers on the project to calculate CFC saturations from previous cruises to regions where data will have been acquired with the underway system. The student will compare these data to the underway data to determine if CFC saturations have changed with time. In the process, these students will learn about oceanography and gain research experience working on one of the most pressing global environmental problems of our time.

了解水质量对于估计海洋的人为二氧化碳吸收很重要。水质量的年龄可以以概率分布函数或运输时间分布（TTD）为特征，而瞬态示踪剂（例如CFCS和SF6）用于约束TTD。但是，约束TTD的不确定性最大来源之一是缺乏有关表面示踪剂饱和度的知识。还需要了解表面饱和度以研究海洋循环模型中的示踪剂的海洋混合和循环，并计算示踪剂库存中的水质量形成速率。为了减少CFC和SF6饱和度的不确定性，夏威夷大学马诺阿大学和哥伦比亚大学Lamont-Dougherty Earth观测站的研究人员将构建一个自动分析系统，以连续测量CFCS和SF6，从表面海洋和大气中进行SF6。尽管海水中CFC和SF6的测量是相当常规的，但拥有一个人操作的自动化系统也将允许从多种人力的各种船只中获取饱和数据。 新的分析系统将在Clivar/重复水文学巡航（例如S4P）和亚热带区域（例如A20/A22/A16）中部署，最终在未来的Clivar/Reprok巡航中将系统部署到冬季的范围很少，而在未来的Clivar/Reprok crumoshich巡游中，将系统部署到未来的水中巡游中。 By documenting variations in tracer saturation levels and environmental variables (e.g., temperature, salinity, wind speeds, mixed layer depth), the research team expects to provide the community with much needed measurements to constrain tracer-based estimates of anthropogenic CO2 uptake, provide better boundary conditions for model calculations using CFCs and SF6, and begin to gain some insights into processes controlling the saturations of these gases in the surface ocean.更广泛的影响瞬态示踪剂对水质量的研究是海洋循环总体研究的重要方面，以及海洋能够通过燃烧化石燃料释放到环境的大量CO2的能力。反过来，由于人类扰动，海洋吸收二氧化碳的气候将适度地球气候变化。对SF6和CFC饱和度的更好了解将减少在确定CFC和SF6清单中的水量形成率时的错误，减少根据SF6和CFC数据确定的循环时间量表中的错误，对利用这些词器的循环模型提供更严格的限制，并降低了基于COFC和SFC的海洋量中的差异，并降低了在COF量的确定范围。作为一个教育组成部分，将在第二个和第三个夏季聘请本科生上班，以计算从以前的巡游到随着地下系统将获取数据的区域的CFC饱和度。 学生将将这些数据与未进行的数据进行比较，以确定CFC饱和度是否随时间变化。在此过程中，这些学生将了解海洋学并获得在我们时代最紧迫的全球环境问题之一的研究经验。