Transport Pathways in the North Atlantic: Searching for Throughput

这项研究旨在通过绘制经向翻转环流的上肢和下肢的交换路径来阐明副热带和亚极地北大西洋的连通性。这项工作的部分动机是欧拉运输量估计与交通部上下部漂浮者和漂流者行为之间的差异。这项工作将利用过去40年来从不同项目积累的大量拉格朗日数据集，以及历史水文数据和测高海面高度。以数据为基础的分析将通过数字模型得到加强。通过将势垒与势涡场进行比较，可以深入了解运动学和动力学之间的关系。最后，应该更好地了解由翻转环流的上肢和下肢组成的水域的停留时间。亚极和亚热带北大西洋之间的连通性是全球海洋环流和气候系统的重要组成部分。由于上层和深海中热量和碳的经向传输在很大程度上依赖于这些环流之间的联系，因此对气候变化的预测将受益于对这种复杂联系的更好理解。这里所描述的动力系统技术的长处和短处的图解也可能使整个海洋物理领域受益。它们过去被应用于小尺度流动和盆地尺度流动的理想化，但从未被应用于北大西洋风生涡旋和MOC的规模和复杂性的流场。

This study aims to clarify the connectivity of the subtropical and subpolar North Atlantic by mapping exchange pathways for the upper and lower limbs of the meridional overturning circulation. The work is motivated in part by discrepancies between Eulerian transport estimates and the behavior of floats and drifters in the upper and lower limbs of the MOC. The work will take advantage of the extensive Lagrangian data set that has accumulated from different programs over the past 40 years, as well as of historical hydrographic data and altimetric sea surface heights. The data-based analysis will be augmented by numerical models. Insights into the relationship between kinematics and dynamics will result from comparisons of barriers with the potential vorticity field. Finally, an improved understanding of residence times for the waters comprising the upper and lower limbs of the overturning circulation should be forthcoming.The connectivity between the subpolar and subtropical North Atlantic constitutes an important piece of the global ocean circulation and climate system. Because the meridional transport of heat and carbon in both the upper and deep ocean depends crucially on the linkage between these gyres, predictions of climate change will benefit from a better understanding of this complex link. The physical oceanographic community at large may also benefit from an illustration of the strengths and weaknesses of the dynamical systems techniques described herein. They have been applied to smaller scale flows and to idealizations of basin scale flows in the past, but never to a flow field of the scale and complexity of the North Atlantic wind-driven gyres and MOC.