Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section.
International audience Decadal changes of the meridional overturning circulation (MOC) at the A25-Ovide section between Portugal and Greenland are investigated in a numerical simulation forced by atmospheric reanalysis data for the period 1965-2004. The intensity, composition, and structure of the u...
Published in: | Journal of Geophysical Research: Oceans |
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Online Access: | https://hal.archives-ouvertes.fr/hal-00836152 https://doi.org/10.1029/2012JC008342 |
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ftccsdartic:oai:HAL:hal-00836152v1 2023-05-15T16:30:06+02:00 Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. Desbruyères, Damien Thierry, Virginie Mercier, Herlé Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2013 https://hal.archives-ouvertes.fr/hal-00836152 https://doi.org/10.1029/2012JC008342 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/2012JC008342 hal-00836152 https://hal.archives-ouvertes.fr/hal-00836152 doi:10.1029/2012JC008342 ISSN: 0148-0227 EISSN: 2156-2202 Journal of Geophysical Research https://hal.archives-ouvertes.fr/hal-00836152 Journal of Geophysical Research, American Geophysical Union, 2013, 118 (1), pp.462-475. ⟨10.1029/2012JC008342⟩ North Atlantic current Meridional Overturning Circulation horizontal gyre Lagrangian decadal variability [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2013 ftccsdartic https://doi.org/10.1029/2012JC008342 2021-10-17T01:39:08Z International audience Decadal changes of the meridional overturning circulation (MOC) at the A25-Ovide section between Portugal and Greenland are investigated in a numerical simulation forced by atmospheric reanalysis data for the period 1965-2004. The intensity, composition, and structure of the upper MOC limb are assessed using a Lagrangian analysis tool. Its mean transport is fed by water masses of two distinct origins: the subtropics and the Labrador Sea. Two vertical overturning cells are consequently identified: a subtropical cell connecting low and high latitudes (12 Sv, 1 Sv = 106 m3 s-1) and a cell internal to the subpolar gyre (4 Sv). The decadal MOC variability is associated with synchronized transport changes of the subtropical and subpolar inflow within the North Atlantic Current (NAC). The varying strength of the MOC is further related to changes in the upper horizontal transport distribution. When the MOC is in a strong phase (early 1990s), the northern branch of the NAC in the Iceland Basin is strong while the southern branch at the Rockall Trough entrance is relatively weak. The inverse situation holds for a persistent weak MOC state (1970s). Contrary to the conclusions of earlier studies, variability in the strength and shape of the subpolar gyre does not stand as the main driver of the changing NAC structure, which is largely induced by the horizontal variability of the subtropical inflow. Additionally, the recently shown intrusion of subtropical waters into the northeastern Atlantic (late 1960s, early 1980s, and 2000s) are shown to primarily occur during periods of weak MOC circulation at A25-Ovide. Article in Journal/Newspaper Greenland Iceland Labrador Sea north atlantic current North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Greenland Rockall Trough ENVELOPE(-15.036,-15.036,53.825,53.825) Journal of Geophysical Research: Oceans 118 1 462 475 |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
North Atlantic current Meridional Overturning Circulation horizontal gyre Lagrangian decadal variability [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
North Atlantic current Meridional Overturning Circulation horizontal gyre Lagrangian decadal variability [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Desbruyères, Damien Thierry, Virginie Mercier, Herlé Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. |
topic_facet |
North Atlantic current Meridional Overturning Circulation horizontal gyre Lagrangian decadal variability [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Decadal changes of the meridional overturning circulation (MOC) at the A25-Ovide section between Portugal and Greenland are investigated in a numerical simulation forced by atmospheric reanalysis data for the period 1965-2004. The intensity, composition, and structure of the upper MOC limb are assessed using a Lagrangian analysis tool. Its mean transport is fed by water masses of two distinct origins: the subtropics and the Labrador Sea. Two vertical overturning cells are consequently identified: a subtropical cell connecting low and high latitudes (12 Sv, 1 Sv = 106 m3 s-1) and a cell internal to the subpolar gyre (4 Sv). The decadal MOC variability is associated with synchronized transport changes of the subtropical and subpolar inflow within the North Atlantic Current (NAC). The varying strength of the MOC is further related to changes in the upper horizontal transport distribution. When the MOC is in a strong phase (early 1990s), the northern branch of the NAC in the Iceland Basin is strong while the southern branch at the Rockall Trough entrance is relatively weak. The inverse situation holds for a persistent weak MOC state (1970s). Contrary to the conclusions of earlier studies, variability in the strength and shape of the subpolar gyre does not stand as the main driver of the changing NAC structure, which is largely induced by the horizontal variability of the subtropical inflow. Additionally, the recently shown intrusion of subtropical waters into the northeastern Atlantic (late 1960s, early 1980s, and 2000s) are shown to primarily occur during periods of weak MOC circulation at A25-Ovide. |
author2 |
Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Desbruyères, Damien Thierry, Virginie Mercier, Herlé |
author_facet |
Desbruyères, Damien Thierry, Virginie Mercier, Herlé |
author_sort |
Desbruyères, Damien |
title |
Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. |
title_short |
Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. |
title_full |
Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. |
title_fullStr |
Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. |
title_full_unstemmed |
Simulated decadal variability of the meridional overturning circulation across the A25-Ovide section. |
title_sort |
simulated decadal variability of the meridional overturning circulation across the a25-ovide section. |
publisher |
HAL CCSD |
publishDate |
2013 |
url |
https://hal.archives-ouvertes.fr/hal-00836152 https://doi.org/10.1029/2012JC008342 |
long_lat |
ENVELOPE(-15.036,-15.036,53.825,53.825) |
geographic |
Greenland Rockall Trough |
geographic_facet |
Greenland Rockall Trough |
genre |
Greenland Iceland Labrador Sea north atlantic current North Atlantic |
genre_facet |
Greenland Iceland Labrador Sea north atlantic current North Atlantic |
op_source |
ISSN: 0148-0227 EISSN: 2156-2202 Journal of Geophysical Research https://hal.archives-ouvertes.fr/hal-00836152 Journal of Geophysical Research, American Geophysical Union, 2013, 118 (1), pp.462-475. ⟨10.1029/2012JC008342⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2012JC008342 hal-00836152 https://hal.archives-ouvertes.fr/hal-00836152 doi:10.1029/2012JC008342 |
op_doi |
https://doi.org/10.1029/2012JC008342 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
118 |
container_issue |
1 |
container_start_page |
462 |
op_container_end_page |
475 |
_version_ |
1766019810112569344 |