Deep Ocean Ventilation Through Antarctic Intermediate Layers (DOVETAIL)

拟议的项目是对威德尔海新形成的底水流出及其向南大西洋扩散的多机构综合研究。它建立在早期成功的研究基础上，这些研究包括：流入东威德尔海的中间水团，它们在威德尔环流内的改变，以及它们与西威德尔海底水形成过程的相互作用。这项研究被称为通过南极中间层的深海通风（DOVETAIL），包括六个组成部分，涉及水文测量、自然示踪剂实验和建模研究。这项研究将在威德尔海和斯科舍海在威德尔-斯科舍汇合处汇合的德雷克海峡以东的中心进行，并将与德国和西班牙的国家南极计划合作进行。这项研究有四个相关的目标。首先是对汇合处威德尔海原水的数量和理化特性进行评价。第二是描述与威德尔-斯科舍合流内密集的南极水域扩张和下沉有关的主要过程。第三是估计世界海洋的通风率，第四是估计区域海洋运输和水文结构的季节性波动，并评估季节至年际变化对威德尔海水通风率的可能影响。深海的通风作用——地表以下的水团上升到海面，以补充大气中的气体，并向大气释放热量——是一种独特的南极现象，它通过影响全球二氧化碳的储存量，并通过调节南半球季节性海冰的数量和范围，对全球变化产生重大影响。DOVETAIL的这个组成部分将对瞬态和稳态示踪剂进行测量，以检查汇流区域各种水团的来源、路径和平均停留时间。将使用氚（氢的一种同位素）、氦-3、氦-4、碳-14、氧-18和各种氟氯化碳来区分汇流水的来源（例如降水、冰川融水、源自大西洋的深水），确定它们在地表的平均停留时间，并使用示踪剂分布作为输入，模拟底层水形成过程***

9528805 Schlosser The propoqed project is a multi-institutional integrated study of the outflow of newly formed bottom water from the Weddell Sea and its dispersion into the South Atlantic Ocean. It builds upon earlier successful studies of the inflow of intermediate water masses into the Eastern Weddell Sea, their modification within the Weddell Gyre, and their interaction with bottom water formation processes in the western Weddell Sea. The study is called Deep Ocean Ventilation Through Antarctic Intermediate Layers (DOVETAIL) and includes six components involving hydrographic measurements, natural tracer experiments, and modeling studies. The study will be centered east of the Drake Passage where water masses from the Weddell Sea and the Scotia Sea come together in the Weddell-Scotia Confluence, and will be carried out in cooperation with the national antarctic programs of Germany and Spain. The study has four related objectives. The first is to assess the quantity and the physical and chemical characteristics of Weddell Sea source waters for the confluence. The second is to describe the dominant processes associated with spreading and sinking of dense antarctic waters within the Weddell-Scotia Confluence. The third is to estimate the ventilation rate of the world ocean, and the fourth is to estimate seasonal fluctuations in the regional ocean transport and hydrographic structure and to assess the likely influence of seasonal to interannual variability on rates of ventilation by Weddell Sea waters. Ventilation of the deep ocean -- the rising of sub-surface water masses to the surface to be recharged with atmospheric gases and to give up heat to the atmosphere -- is a uniquely antarctic phenomenon that has significant consequences for global change by affecting the global reservoir of carbon dioxide, and by modulating the amount and extent of seasonal sea ice in the southern hemisphere. This component of DOVETAIL will make measurem ents on both transient and steady-state tracers to examine the sources, pathways, and average residence times of the various water masses in the confluence region. Tritium (an isotope of hydrogen), helium-3, helium-4, carbon-14, oxygen-18, and various chlorofluorocarbons will be used to differentiate the sources of confluence water (e.g. precipitation, glacial melt water, deep water of Atlantic origin), to determine their average residence times at the surface, and to use the tracer distributions as input to model simulations of the bottom water formation process ***