Frajka-Williams, Eleanor and Meinen, Christopher S. and Johns, W.E. and Smeed, David A. and Duchez, A. and Lawrence, A.J. and Cuthbertson, D.A. and McCarthy, Gerard and Bryden, H.L. and Baringer, M.O. and Moat, B. I. and Rayner, D. (2016) Compensation between meridional flow components of the Atlantic MOC at 26° N. Ocean Science, 12 (2). pp. 481-493. ISSN 1812-0784

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Abstract

From ten years of observations of the Atlantic meridional overturning circulation (MOC) at 26° N (2004–2014), we revisit the question of flow compensation between components of the circulation. Contrasting with early results from the observations, transport variations of the Florida Current (FC) and upper mid-ocean (UMO) transports (top 1000 m east of the Bahamas) are now found to compensate on sub-annual timescales. The observed compensation between the FC and UMO transports is associated with horizontal circulation and means that this part of the correlated variability does not project onto the MOC. A deep baroclinic response to wind-forcing (Ekman transport) is also found in the lower North Atlantic Deep Water (LNADW; 3000–5000 m) transport. In contrast, co-variability between Ekman and the LNADW transports does contribute to overturning. On longer timescales, the southward UMO transport has continued to strengthen, resulting in a continued decline of the MOC. Most of this interannual variability of the MOC can be traced to changes in isopycnal displacements on the western boundary, within the top 1000 m and below 2000 m. Substantial trends are observed in isopycnal displacements in the deep ocean, underscoring the importance of deep boundary measurements to capture the variability of the Atlantic MOC.

Item Type:	Article
Keywords:	Wind; Eddy-filled Ocean; Transport Variability; Interannual Variability; Boundary Density Variations; North-Atlantic; Florida current; Oceanography; Overturning Circulation; Meteorology & Athmospheric Sciences;
Academic Unit:	Faculty of Social Sciences > Geography Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	12181
Identification Number:	https://doi.org/10.5194/os-12-481-2016
Depositing User:	Gerard McCarthy
Date Deposited:	20 Jan 2020 11:42
Journal or Publication Title:	Ocean Science
Publisher:	European Geosciences Union
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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