Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean.
International audience The authors investigate the nature of the interannual variability of the meridional overturning circulation (MOC) of the North Atlantic Ocean using an Estimating the Circulation and Climate of the Ocean (ECCO) assimilation product for the period of 1993–2003. The time series o...
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ftunivnantes:oai:HAL:hal-00400047v1 2023-05-15T17:29:13+02:00 Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. Cabanes, Cécile Lee, Tong Fu, Lee-Lueng 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) Jet Propulsion Laboratory (JPL) NASA-California Institute of Technology (CALTECH) 2008-02 https://hal.science/hal-00400047 https://doi.org/10.1175/2007JPO3726.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/2007JPO3726.1 hal-00400047 https://hal.science/hal-00400047 doi:10.1175/2007JPO3726.1 ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal.science/hal-00400047 Journal of Physical Oceanography, 2008, 38 (2), pp.467-480. ⟨10.1175/2007JPO3726.1⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2008 ftunivnantes https://doi.org/10.1175/2007JPO3726.1 2023-02-08T01:29:39Z International audience The authors investigate the nature of the interannual variability of the meridional overturning circulation (MOC) of the North Atlantic Ocean using an Estimating the Circulation and Climate of the Ocean (ECCO) assimilation product for the period of 1993–2003. The time series of the first empirical orthogonal function of the MOC is found to be correlated with the North Atlantic Oscillation (NAO) index, while the associated circulation anomalies correspond to cells extending over the full ocean depth. Model sensitivity experiments suggest that the wind is responsible for most of this interannual variability, at least south of 40°N. A dynamical decomposition of the meridional streamfunction allows a further look into the mechanisms. In particular, the contributions associated with 1) the Ekman flow and its depth-independent compensation, 2) the vertical shear flow, and 3) the barotropic gyre flowing over zonally varying topography are examined. Ekman processes are found to dominate the shorter time scales (1.5–3 yr), while for longer time scales (3–10 yr) the MOC variations associated with vertical shear flow are of greater importance. The latter is primarily caused by heaving of the pycnocline in the western subtropics associated with the stronger wind forcing. Finally, how these changes in the MOC affect the meridional heat transport (MHT) is examined. It is found that overall, Ekman processes explain a larger part of interannual variability (3–10 yr) for MHT (57%) than for the MOC (33%). Article in Journal/Newspaper North Atlantic North Atlantic oscillation Université de Nantes: HAL-UNIV-NANTES Journal of Physical Oceanography 38 2 467 480 |
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Open Polar |
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Université de Nantes: HAL-UNIV-NANTES |
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ftunivnantes |
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 Cabanes, Cécile Lee, Tong Fu, Lee-Lueng Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience The authors investigate the nature of the interannual variability of the meridional overturning circulation (MOC) of the North Atlantic Ocean using an Estimating the Circulation and Climate of the Ocean (ECCO) assimilation product for the period of 1993–2003. The time series of the first empirical orthogonal function of the MOC is found to be correlated with the North Atlantic Oscillation (NAO) index, while the associated circulation anomalies correspond to cells extending over the full ocean depth. Model sensitivity experiments suggest that the wind is responsible for most of this interannual variability, at least south of 40°N. A dynamical decomposition of the meridional streamfunction allows a further look into the mechanisms. In particular, the contributions associated with 1) the Ekman flow and its depth-independent compensation, 2) the vertical shear flow, and 3) the barotropic gyre flowing over zonally varying topography are examined. Ekman processes are found to dominate the shorter time scales (1.5–3 yr), while for longer time scales (3–10 yr) the MOC variations associated with vertical shear flow are of greater importance. The latter is primarily caused by heaving of the pycnocline in the western subtropics associated with the stronger wind forcing. Finally, how these changes in the MOC affect the meridional heat transport (MHT) is examined. It is found that overall, Ekman processes explain a larger part of interannual variability (3–10 yr) for MHT (57%) than for the MOC (33%). |
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) Jet Propulsion Laboratory (JPL) NASA-California Institute of Technology (CALTECH) |
format |
Article in Journal/Newspaper |
author |
Cabanes, Cécile Lee, Tong Fu, Lee-Lueng |
author_facet |
Cabanes, Cécile Lee, Tong Fu, Lee-Lueng |
author_sort |
Cabanes, Cécile |
title |
Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. |
title_short |
Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. |
title_full |
Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. |
title_fullStr |
Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. |
title_full_unstemmed |
Mechanisms of Interannual Variations of the Meridional Overturning Circulation of the North Atlantic Ocean. |
title_sort |
mechanisms of interannual variations of the meridional overturning circulation of the north atlantic ocean. |
publisher |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.science/hal-00400047 https://doi.org/10.1175/2007JPO3726.1 |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal.science/hal-00400047 Journal of Physical Oceanography, 2008, 38 (2), pp.467-480. ⟨10.1175/2007JPO3726.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/2007JPO3726.1 hal-00400047 https://hal.science/hal-00400047 doi:10.1175/2007JPO3726.1 |
op_doi |
https://doi.org/10.1175/2007JPO3726.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
38 |
container_issue |
2 |
container_start_page |
467 |
op_container_end_page |
480 |
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1766122864541433856 |