Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010
International audience The meridional overturning circulation (MOC) in the North Atlantic transports heat from the subtropics to high latitudes and hence plays an important role in the Earth’s climate. A region crucial for the MOC is the northern North Atlantic and the adjacent Nordic Seas, where wa...
Published in: | Progress in Oceanography |
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Language: | English |
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Online Access: | https://hal.archives-ouvertes.fr/hal-01151408 https://doi.org/10.1016/j.pocean.2013.11.001 |
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ftccsdartic:oai:HAL:hal-01151408v1 2023-05-15T16:28:57+02:00 Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 Mercier, Herlé Lherminier, Pascale Sarafanov, Artem Gaillard, Fabienne Daniault, Nathalie Desbruyères, Damien Falina, Anastasia Ferron, Bruno Gourcuff, Claire Huck, Thierry Thierry, Virginie 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) P.P. Shirshov Institute of Oceanology (SIO) Russian Academy of Sciences Moscow (RAS) 2015-03 https://hal.archives-ouvertes.fr/hal-01151408 https://doi.org/10.1016/j.pocean.2013.11.001 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.pocean.2013.11.001 hal-01151408 https://hal.archives-ouvertes.fr/hal-01151408 doi:10.1016/j.pocean.2013.11.001 ISSN: 0079-6611 Progress in Oceanography https://hal.archives-ouvertes.fr/hal-01151408 Progress in Oceanography, Elsevier, 2015, 132, pp.250-261. ⟨10.1016/j.pocean.2013.11.001⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2015 ftccsdartic https://doi.org/10.1016/j.pocean.2013.11.001 2021-11-21T03:09:39Z International audience The meridional overturning circulation (MOC) in the North Atlantic transports heat from the subtropics to high latitudes and hence plays an important role in the Earth’s climate. A region crucial for the MOC is the northern North Atlantic and the adjacent Nordic Seas, where waters transported northward in the MOC upper limb progressively cool, gain density and eventually sink. Here we discuss the variability of the gyre circulation, the MOC and heat flux as quantified from a joint analysis of hydrographic and velocity data from six repeats of the Greenland to Portugal OVIDE section (1997–2010), satellite altimetry and Argo float measurements. For each repeat of the OVIDE section, the full-depth absolute circulation and transports were assessed using an inverse model constrained by ship-mounted Acoustic Doppler Current Profiler data and by an overall mass balance. The obtained circulation patterns revealed remarkable transport changes in the whole water column and evidenced large variations (up to 50% of the lowest value) in the magnitude of the MOC computed in density coordinates (MOCσ). The extent and time scales of the MOCσ variability in 1993–2010 were then evaluated using a monthly MOCσ index built upon altimetry and Argo. The MOCσ index, validated by the good agreement with the estimates from repeat hydrographic surveys, shows a large variability of the MOCσ at OVIDE on monthly to decadal time scales. The intra-annual variability is dominated by the seasonal component with peak-to-peak amplitude of 4.3 Sv (1 Sv = 106 m3 s–1). On longer time scales, the MOCσ index varies from less than 15 Sv to about 25 Sv. It averages to 18.1 ± 1.4 Sv and shows an overall decline of 2.5 ± 1.4 Sv (95% confidence interval) between 1993 and 2010. The heat flux estimates from repeat hydrographic surveys, which vary between 0.29 and 0.70 ± 0.05 PW, indicate that the heat flux across the OVIDE section is linearly related to the MOCσ intensity (0.054 PW/Sv). Article in Journal/Newspaper Greenland Nordic Seas North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Greenland Progress in Oceanography 132 250 261 |
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 |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Mercier, Herlé Lherminier, Pascale Sarafanov, Artem Gaillard, Fabienne Daniault, Nathalie Desbruyères, Damien Falina, Anastasia Ferron, Bruno Gourcuff, Claire Huck, Thierry Thierry, Virginie Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience The meridional overturning circulation (MOC) in the North Atlantic transports heat from the subtropics to high latitudes and hence plays an important role in the Earth’s climate. A region crucial for the MOC is the northern North Atlantic and the adjacent Nordic Seas, where waters transported northward in the MOC upper limb progressively cool, gain density and eventually sink. Here we discuss the variability of the gyre circulation, the MOC and heat flux as quantified from a joint analysis of hydrographic and velocity data from six repeats of the Greenland to Portugal OVIDE section (1997–2010), satellite altimetry and Argo float measurements. For each repeat of the OVIDE section, the full-depth absolute circulation and transports were assessed using an inverse model constrained by ship-mounted Acoustic Doppler Current Profiler data and by an overall mass balance. The obtained circulation patterns revealed remarkable transport changes in the whole water column and evidenced large variations (up to 50% of the lowest value) in the magnitude of the MOC computed in density coordinates (MOCσ). The extent and time scales of the MOCσ variability in 1993–2010 were then evaluated using a monthly MOCσ index built upon altimetry and Argo. The MOCσ index, validated by the good agreement with the estimates from repeat hydrographic surveys, shows a large variability of the MOCσ at OVIDE on monthly to decadal time scales. The intra-annual variability is dominated by the seasonal component with peak-to-peak amplitude of 4.3 Sv (1 Sv = 106 m3 s–1). On longer time scales, the MOCσ index varies from less than 15 Sv to about 25 Sv. It averages to 18.1 ± 1.4 Sv and shows an overall decline of 2.5 ± 1.4 Sv (95% confidence interval) between 1993 and 2010. The heat flux estimates from repeat hydrographic surveys, which vary between 0.29 and 0.70 ± 0.05 PW, indicate that the heat flux across the OVIDE section is linearly related to the MOCσ intensity (0.054 PW/Sv). |
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) P.P. Shirshov Institute of Oceanology (SIO) Russian Academy of Sciences Moscow (RAS) |
format |
Article in Journal/Newspaper |
author |
Mercier, Herlé Lherminier, Pascale Sarafanov, Artem Gaillard, Fabienne Daniault, Nathalie Desbruyères, Damien Falina, Anastasia Ferron, Bruno Gourcuff, Claire Huck, Thierry Thierry, Virginie |
author_facet |
Mercier, Herlé Lherminier, Pascale Sarafanov, Artem Gaillard, Fabienne Daniault, Nathalie Desbruyères, Damien Falina, Anastasia Ferron, Bruno Gourcuff, Claire Huck, Thierry Thierry, Virginie |
author_sort |
Mercier, Herlé |
title |
Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 |
title_short |
Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 |
title_full |
Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 |
title_fullStr |
Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 |
title_full_unstemmed |
Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010 |
title_sort |
variability of the meridional overturning circulation at the greenland–portugal ovide section from 1993 to 2010 |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal.archives-ouvertes.fr/hal-01151408 https://doi.org/10.1016/j.pocean.2013.11.001 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Nordic Seas North Atlantic |
genre_facet |
Greenland Nordic Seas North Atlantic |
op_source |
ISSN: 0079-6611 Progress in Oceanography https://hal.archives-ouvertes.fr/hal-01151408 Progress in Oceanography, Elsevier, 2015, 132, pp.250-261. ⟨10.1016/j.pocean.2013.11.001⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.pocean.2013.11.001 hal-01151408 https://hal.archives-ouvertes.fr/hal-01151408 doi:10.1016/j.pocean.2013.11.001 |
op_doi |
https://doi.org/10.1016/j.pocean.2013.11.001 |
container_title |
Progress in Oceanography |
container_volume |
132 |
container_start_page |
250 |
op_container_end_page |
261 |
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1766018642229592064 |