Oceanic Uptake of Carbon Dioxide and its Transport via the South Atlantic Ventilation

1980 - 1985年期间，美国国家科学基金会资助了两项大西洋瞬态示踪剂测量运动（TTO/NAS和TTO/赤道）。建立这一海洋盆地模型的完整数据库将包括一项南大西洋研究，以便：2.确定CO2运输及其对世界气候的影响；2 .限制该地区主要洋流的模式；确认已观测到的向温跃层添加新碳的速率增加了5倍。这项研究的八个组成部分将由来自LDGO、普林斯顿大学、华盛顿大学、WHOI和SIO的研究人员进行。这些科学家成功地完成了以前在赤道和北大西洋的研究，从而建立了良好的记录。它们将提供物理和化学专门知识，这些专门知识将用于合作努力，以实现地球化学研究的目标。这一组成部分旨在提高我们对不同气候区形成的南极水团对二氧化碳动态输送的理解。以往的研究表明，在南纬40°~ 50°S的纬度范围内存在一个突出的环极CO2汇区，并与亚热带暖水与亚南极冷水的汇合带密切相关。该区域约占全球海洋吸收二氧化碳通量的40%。该地区地表水的低pCO2值主要是由于温暖的副热带环流的冷却作用以及冷水与高pco的混合作用所致。以及营养丰富的南极水域CO2的光合作用进一步降低了地表水的pCO2值。在该汇流带附近，高盐度副热带海水的冷却主要导致500米左右的水柱有效倾覆。这个过程将把这个二氧化碳汇带的地表水吸收的二氧化碳输送到南大西洋温跃层。拟议调查的主要目标之一是利用实验期间获得的示踪剂和二氧化碳数据来估计这种运输的速率。

Two campaigns to measure transient tracers in the Atlantic Ocean (TTO/NAS and TTO/Equatorial) were funded by NSF during the period from 1980 to 1985. A complete data base for modelling this ocean basin would include a South Atlantic Study to: 1.Determine CO2 transports and their influence on world climate, 2.Constrain models of major ocean currents in this area, and 3.Confirm an observed 5-fold increase in the addition rate of new carbon to the thermocline. Eight components of such a study will be performed by investigators from LDGO, Princeton, University of Washington, WHOI, and SIO. The track record of these scientists is well established by successful completion of previous studies in the Equatorial and North Atlantic. They will provide physical and chemical expertise which will be directed toward a cooperative effort to reach the goals of the geochemical study. This component is aimed at improving our understanding of the dynamic transport of CO2 by Antarctic water masses formed in zones of different climates. Previous investigations showed that a prominent circumpolar CO2 sink zone is located in a latitudinal range of 40 degrees S - 50 degrees S, and that it is closely associated with the zone of confluence of the warm Subtropical water with the cold Subantarctic water. This zone accounts for about 40% of the global oceanic uptake flux for CO2. The low pCO2 values in the surface water of this zone are attributed mainly to the effect of cooling of the warm Subtropical gyre waters and to the mixing of the cooled water with the high-pCO. and high-nutrient Antarctic waters. Photosynthetic utilization of CO2 further reduces the surface water pCO2 value. In the vicinity of this confluence zone, an effective overturning of the water column down to about 500 meters is induced mainly by cooling of the high-salinity Subtropical waters. This process would transport the CO2 taken up by the surface water of this CO2 sink zone into the South Atlantic thermocline. One of the major objectives of the proposed investigation is to estimate the rate of this transport using the tracer and CO2 data obtained during the experiment.