Solodoch A. auteur aut IRD McWilliams J. C. auteur aut IRD Stewart A. L. auteur aut IRD Gula J. auteur aut IRD Renault Lionel auteur aut IRD text journalArticle eng text/pdf born digital access The southward-flowing deep limb of the Atlantic meridional overturning circulation is composed of both the deep western boundary current (DWBC) and interior pathways. The latter are fed by "leakiness' from the DWBC in the Newfoundland Basin. However, the cause of this leakiness has not yet been explored mechanistically. Here the statistics and dynamics of the DWBC leakiness in the Newfoundland Basin are explored using two float datasets and a high-resolution numerical model. The float leakiness around Flemish Cap is found to be concentrated in several areas (hot spots) that are collocated with bathymetric curvature and steepening. Numerical particle advection experiments reveal that the Lagrangian mean velocity is offshore at these hot spots, while Lagrangian variability is minimal locally. Furthermore, model Eulerian mean streamlines separate from the DWBC to the interior at the leakiness hot spots. This suggests that the leakiness of Lagrangian particles is primarily accomplished by an Eulerian mean flow across isobaths, though eddies serve to transfer around 50% of the Lagrangian particles to the leakiness hot spots via chaotic advection, and rectified eddy transport accounts for around 50% of the offshore flow along the southern face of Flemish Cap. Analysis of the model's energy and potential vorticity budgets suggests that the flow is baroclinically unstable after separation, but that the resulting eddies induce modest modifications of the mean potential vorticity along streamlines. These results suggest that mean uncompensated leakiness occurs mostly through inertial separation, for which a scaling analysis is presented. Implications for leakiness of other major boundary current systems are discussed. specialized ATLANTIQUE NORD TERRE NEUVE ET LABRADOR 032 020 50 7 1989-2016 2020 0022-3670 https://www.documentation.ird.fr/hor/fdi:010080924 10.1175/jpo-d-19-0247.1 0022-3670 [F B010080924] https://www.documentation.ird.fr/hor/fdi:010080924 https://www.documentation.ird.fr/intranet/publi/2021/03/010080924.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2021-04-01 2025-02-24 fdi:010080924 fre