Transports and variability-driving mechanisms in Flemish Pass at the western boundary of the subpolar North Atlantic (FLEPVAR)

拉布拉多海形成的拉布拉多海水（LSW）对北大西洋深水（NADW）的贡献最小，后者是形成大西洋经向翻转环流（MOC）冷回流的水团团。MOC强度的变化可以调节气候变率；这种变化被认为与LSW形成的变化有关。深西边界流（DWBC）是新形成的LSW向南的主要通道。拉布拉多海南部出口的地形障碍将DWBC分裂为通过佛兰德山口（~1200m）携带LSW的上分支和沿着佛兰德帽周围大陆斜坡携带所有NADW分量的分支。到目前为止，通过佛兰德山口的运输及其对MOC的贡献仍然不确定，通道对LSW输出的重要性及其相关变率尚不清楚。在这个项目中，通过佛兰德山口的运输将被量化，并将研究驱动和控制流量变化的机制。该项目主要关注以下问题：通过佛兰德山口的水的运输量及其相关的变异性是多少？哪些过程驱动可变性？通过佛兰德斯山口的深水出口与MOC的相关性是什么，特别是与DWBC出口相比？两个深水出口通道（通过佛兰德山口或绕过佛兰德山口）是否相连？什么过程控制着深水流入佛兰德山口？为了回答这些问题，Flemish Pass的船舶测量和系泊仪器的时间序列将与两个最先进的高分辨率海洋模型的输出相结合进行分析。

Labrador Sea Water (LSW) formed in the Labrador Sea constitutes the lightest contribution to North Atlantic Deep Water (NADW), a conglomerate of water masses that form the cold return flow of the Atlantic meridional overturning circulation (MOC). Climate variability can be modulated by changes in the MOC strength; such changes are thought to be linked to variations in LSW formation. The Deep Western Boundary Current (DWBC) is the main southward pathway for newly formed LSW. Topographic obstacles at the southern exit of the Labrador Sea split the DWBC into an upper branch carrying LSW through Flemish Pass (~1200m sill depth) and a branch carrying all NADW components along the continental slope around Flemish Cap. Up to now, transports through Flemish Pass and their contribution to the MOC are still uncertain, the importance of the pass for the export of LSW and its associated variability are yet unknown. In this project the transports through Flemish Pass will be quantified, and mechanisms driving and governing the variability of the flow will be investigated.The project focuses on the following questions: What is the magnitude of transports for waters passingthrough Flemish Pass and their associated variability? Which processes drive the variability? What is the relevance of the deep water export through Flemish Pass for the MOC, especially when compared to the DWBC export? Are both deep water export pathways (through Flemish Pass or around Flemish Cap) coupled? What processes govern the inflow of deep water into Flemish Pass? To answers these questions, ship-based measurements and time series from moored instruments in the Flemish Pass will be analyzed in conjunction with output from two state-of-the-art ocean models run at high-resolution.