Variability in water mass formation and ventilation rates in the southwestern Pacific Ocean based on Repeat Hydrography CFC measurements

在这个项目中，美国调查员将与澳大利亚海洋学家合作，重新利用被美国CLIVAR/CO碳(气候变异性和可预测性)重复水文计划确定为必要的两个水文地段。测定了2007-2008年塔斯马尼亚至南极140‘E断面和2008-2009年50’S至赤道170‘W断面上溶解的氯氟烃(CFCs)。这将是这两个部门自1990年以来第四次使用氯氟化碳示踪剂和碳系统测量。所有三种氯氟化碳：cfc-11、cfc-12和cfc-113将在两个部分进行测量，SF6将至少在太平洋线路上进行测量。这些示踪测量是对水文观测的补充，水文观测将包括溶解的营养物质和碳系统参数。CFCs强调了新通风的冷水和起源于北方的古老的绕极水之间的对比，并提供了一个“时钟”，以帮助理解位于南极绕极洋流北侧的环极带中观察到的水团性质的变化，该带与亚南极模式水和南极中间水所在的厚厚的冷混合层有关。这些测量结果将与澳大利亚同事合作进行解释。将利用各种数据分析方法，包括与一般环流模型产出的比较，来解释氟氯化碳浓度和得出的年龄的变化。数值模型和渡越时间分布将被用来解释pCFC年龄。拟议工作的更广泛影响这项拟议的研究继续与澳大利亚科学家进行长期合作，继续培训一名将参加其中一次探险的研究生进行模型数据比较，并提供关于中间成水率和底层水域变化的数据，这将有助于我们更好地了解南大洋在气候变化和人为二氧化碳吸收中的作用。澳大利亚海洋界没有海水氟氯化碳测量实验室。这些氯氟化碳测量对解释澳大利亚研究人员的水文和碳系统测量做出了重要贡献。澳大利亚海洋学家同意CLIVAR/Carbon Repeat水文计划的数据政策。这些来自海洋区域之一的数据对研究海洋对表面强迫变化的反应具有潜在的重要意义，这些数据将在航行后不久公开提供。

In this project, the US investigator will collaborate with Australian oceanographers to reoccupy two hydrographic sections that have been identified as essential by the U.S. CLIVAR/Carbon (CLImate VARiability and predictability) Repeat Hydrography Program. The dissolved chlorofluorocarbons (CFCs) on sections between Tasmania and Antarctica along 140'E in 2007-8 and along 170'W between 50'S and the equator in 2008-9 will be measured. This will be the fourth occupation of both these sections with chlorofluorocarbon tracers (CFC) and carbon system measurements since 1990. All three Chlorofluorocarbons: CFC-11, CFC-12, and CFC-113 will be measured on both sections, and SF6 will be measured on at least the pacific line. These tracer measurements complement the hydrographic observations that will include dissolved nutrients and carbon system parameters. The CFCs emphasize the contrast between newly-ventilated cold waters and the older, circumpolar waters of northern origin, and provide a "clock" to help understand observed changes in water mass properties in a circumpolar band located on the north side of the Antarctic Circumpolar Current, associated with the thick cold mixed layers where Subantarctic Mode Water and Antarctic Intermediate Water. These measurements will be interpreted in collaboration with the Australian colleagues. A variety of approaches to data analysis, including comparison with general circulation model output, will be utilized to interpret changes in the CFC concentrations and derived ages. Both numerical models and transit time distributions will be utilized to interpret the pCFC ages. Broader Impacts of Proposed WorkThis proposed research continues a long-term collaboration with Australian scientists, continues the training of a graduate student in model-data comparisons who will participate one of the expeditions, and provides data on changes in intermediate water formation rates and bottom waters that will help us better understand the role of the Southern Ocean in climate change and anthropogenic CO2 uptake. There is no seawater CFC measurement laboratory in the Australian oceanographic community. These CFC measurements make an important contribution to the interpretation of both the hydrographic and carbon system measurements of the Australian researchers. The Australian oceanographers have agreed to the data policy of the CLIVAR/Carbon Repeat Hydrography Program. These data from one of the regions of the ocean that is potentially important to studies of the ocean's response to changes in surface forcing will be publicly available soon after the voyages.