The upper, deep, abyssal and overturning circulation in the Atlantic Ocean at 30°S in 2003 and 2011
The upper, deep, abyssal and overturning circulation in the Atlantic Ocean at 30°S in 2003 and 2011
Mass transports for the thermocline, intermediate, deep and abyssal layers in the Atlantic Ocean, at 30°S and for 2003 and 2011, have been estimated using data from GO-SHIP hydrographic transoceanic sections and applying three inverse models with different constraints. The uppermost layers comprise South Atlantic Central Water (SACW) and Antarctic Intermediate Water (AAIW), with a net northward transport in the range of 12.1–14.7 Sv in 2003 and 11.7–17.7 Sv in 2011, which can be considered as the northward returning limb of the Meridional Overturning Circulation (MOC). The western boundary Brazil Current transports twice as much SACW in 2003 (−20.2 ± 0.7 Sv) than in 2011 (−9.7 ± 0.7 Sv). A poleward current consisting of AAIW and Upper Circumpolar Deep Water (UCDW) flows beneath the Brazil Current. The eastern boundary Benguela Current, characterized by a high mesoscale eddy activity, transports 15.6 ± 0.9 Sv in 2003 and 11.2 ± 0.8 Sv in 2011, east of the Walvis Ridge. In the ocean interior, the northward flow is mainly located east of the Mid Atlantic Ridge (MAR) where Agulhas Rings (ARs), observed in both 2003 and 2011, transport warm and salty water from the Indian to the Atlantic Ocean. For the deep layers, the southward transport of North Atlantic Deep Water (NADW) occurs as the Deep Western Boundary Current and also in the eastern basin. The western and eastern basins transport similar amounts of NADW to the south during both years, although the eastern pathway changes substantially between both years. The total NADW transport, which is also considered the MOC, is in the range 16.3–24.5 Sv in 2003 and 17.1–29.6 Sv in 2011, hence with no significant change.
Hernández-Guerra, Alonso
09fa215a-646f-4e71-8473-0657a4531d67
Talley, Lynne D.
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Pelegrí, José Luis
689c185b-2709-43bb-afdf-29cd508b4b44
Vélez-Belchí, Pedro
dde80f02-f2fd-45d3-8c93-f548fcce5541
Baringer, Molly O.
05e0f722-83ee-4dc2-ac6e-2505c8b29f31
Macdonald, Alison M.
44a94888-e58a-454e-8f29-dad6ea845dcd
McDonagh, Elaine L.
47e26eeb-b774-4068-af07-31847e42b977
September 2019
Hernández-Guerra, Alonso
09fa215a-646f-4e71-8473-0657a4531d67
Talley, Lynne D.
45fc25e8-f845-42ac-804e-7052c8c16dcf
Pelegrí, José Luis
689c185b-2709-43bb-afdf-29cd508b4b44
Vélez-Belchí, Pedro
dde80f02-f2fd-45d3-8c93-f548fcce5541
Baringer, Molly O.
05e0f722-83ee-4dc2-ac6e-2505c8b29f31
Macdonald, Alison M.
44a94888-e58a-454e-8f29-dad6ea845dcd
McDonagh, Elaine L.
47e26eeb-b774-4068-af07-31847e42b977
Hernández-Guerra, Alonso, Talley, Lynne D., Pelegrí, José Luis, Vélez-Belchí, Pedro, Baringer, Molly O., Macdonald, Alison M. and McDonagh, Elaine L.
(2019)
The upper, deep, abyssal and overturning circulation in the Atlantic Ocean at 30°S in 2003 and 2011.
Progress in Oceanography, 176, [102136].
(doi:10.1016/j.pocean.2019.102136).
Abstract
Mass transports for the thermocline, intermediate, deep and abyssal layers in the Atlantic Ocean, at 30°S and for 2003 and 2011, have been estimated using data from GO-SHIP hydrographic transoceanic sections and applying three inverse models with different constraints. The uppermost layers comprise South Atlantic Central Water (SACW) and Antarctic Intermediate Water (AAIW), with a net northward transport in the range of 12.1–14.7 Sv in 2003 and 11.7–17.7 Sv in 2011, which can be considered as the northward returning limb of the Meridional Overturning Circulation (MOC). The western boundary Brazil Current transports twice as much SACW in 2003 (−20.2 ± 0.7 Sv) than in 2011 (−9.7 ± 0.7 Sv). A poleward current consisting of AAIW and Upper Circumpolar Deep Water (UCDW) flows beneath the Brazil Current. The eastern boundary Benguela Current, characterized by a high mesoscale eddy activity, transports 15.6 ± 0.9 Sv in 2003 and 11.2 ± 0.8 Sv in 2011, east of the Walvis Ridge. In the ocean interior, the northward flow is mainly located east of the Mid Atlantic Ridge (MAR) where Agulhas Rings (ARs), observed in both 2003 and 2011, transport warm and salty water from the Indian to the Atlantic Ocean. For the deep layers, the southward transport of North Atlantic Deep Water (NADW) occurs as the Deep Western Boundary Current and also in the eastern basin. The western and eastern basins transport similar amounts of NADW to the south during both years, although the eastern pathway changes substantially between both years. The total NADW transport, which is also considered the MOC, is in the range 16.3–24.5 Sv in 2003 and 17.1–29.6 Sv in 2011, hence with no significant change.
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Accepted/In Press date: 22 July 2019
e-pub ahead of print date: 23 July 2019
Published date: September 2019
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Local EPrints ID: 435215
URI: http://eprints.soton.ac.uk/id/eprint/435215
ISSN: 0079-6611
PURE UUID: 89de7d63-08e4-4e02-a561-8ae2a2944cc7
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Date deposited: 25 Oct 2019 16:30
Last modified: 16 Mar 2024 03:49
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Author:
Alonso Hernández-Guerra
Author:
Lynne D. Talley
Author:
José Luis Pelegrí
Author:
Pedro Vélez-Belchí
Author:
Molly O. Baringer
Author:
Alison M. Macdonald
Author:
Elaine L. McDonagh
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