Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model
International audience Recent observations and modeling studies have stressed the influence of surface salinity perturbations on the North Atlantic circulation over the past few decades. As a step toward the estimation of the sensitivity of the thermohaline circulation to salinity anomalies, optimal...
Published in: | Journal of Physical Oceanography |
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Main Authors: | , , , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2008
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Online Access: | https://hal.science/hal-00400418 https://hal.science/hal-00400418/document https://hal.science/hal-00400418/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Optimal%20Surface%20Salinity%20Perturbations%20of%20the%20Meridional%20Overturning%20and%20Heat%20Transport%20in%20a%20Global%20Ocean%20General%20Circulation%20Model.pdf https://doi.org/10.1175/2008JPO3875.1 |
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HAL Sorbonne Université |
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English |
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[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
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[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Sévellec, Florian Huck, Thierry Ben Jelloul, Mahdi Grima, Nicolas Vialard, Jérôme Weaver, Anthony T. Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Recent observations and modeling studies have stressed the influence of surface salinity perturbations on the North Atlantic circulation over the past few decades. As a step toward the estimation of the sensitivity of the thermohaline circulation to salinity anomalies, optimal initial surface salinity perturbations are computed and described for a realistic mean state of a global ocean general circulation model [Océan Parallélisé (OPA)]; optimality is defined successively with respect to the meridional overturning circulation intensity and the meridional heat transport maximum. Although the system is asymptotically stable, the nonnormality of the dynamics is able to produce a transient growth through an initial stimulation. Optimal perturbations are calculated subject to three constraints: the perturbation applies to surface salinity; the perturbation conserves the global salt content; and the perturbation is normalized, to remove the degeneracy in the linear maximization problem. Maximization using Lagrangian multipliers leads to explicit solutions (rather than eigenvalue problems), involving the integration of the model adjoint for each value to maximize. The most efficient transient growth for the intensity of the meridional overturning circulation appears for a delay of 10.5 yr after the perturbation by the optimal surface salinity anomaly. This optimal growth is induced by an initial anomaly located north of 50°N. In the same way, the most efficient transient growth for the intensity of the meridional heat transport appears for a shorter delay of 2.2 yr after the perturbation by the optimal surface salinity anomaly. This initial optimal perturbation corresponds to a zonal salinity gradient around 24°N. The optimal surface salinity perturbations studied herein yield upper bounds on the intensity of the response in meridional overturning circulation and meridional heat transport. Using typical amplitudes of the Great Salinity Anomalies, the upper bounds for the associated variability ... |
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) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS) |
format |
Article in Journal/Newspaper |
author |
Sévellec, Florian Huck, Thierry Ben Jelloul, Mahdi Grima, Nicolas Vialard, Jérôme Weaver, Anthony T. |
author_facet |
Sévellec, Florian Huck, Thierry Ben Jelloul, Mahdi Grima, Nicolas Vialard, Jérôme Weaver, Anthony T. |
author_sort |
Sévellec, Florian |
title |
Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model |
title_short |
Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model |
title_full |
Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model |
title_fullStr |
Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model |
title_full_unstemmed |
Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model |
title_sort |
optimal surface salinity perturbations of the meridional overturning and heat transport in a global ocean general circulation model |
publisher |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.science/hal-00400418 https://hal.science/hal-00400418/document https://hal.science/hal-00400418/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Optimal%20Surface%20Salinity%20Perturbations%20of%20the%20Meridional%20Overturning%20and%20Heat%20Transport%20in%20a%20Global%20Ocean%20General%20Circulation%20Model.pdf https://doi.org/10.1175/2008JPO3875.1 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal.science/hal-00400418 Journal of Physical Oceanography, 2008, 38 (12), pp.2739-2754. ⟨10.1175/2008JPO3875.1⟩ |
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op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/2008JPO3875.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
38 |
container_issue |
12 |
container_start_page |
2739 |
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ftsorbonneuniv:oai:HAL:hal-00400418v1 2024-05-19T07:45:26+00:00 Optimal surface salinity perturbations of the meridional overturning and heat transport in a global Ocean general circulation model Sévellec, Florian Huck, Thierry Ben Jelloul, Mahdi Grima, Nicolas Vialard, Jérôme Weaver, Anthony T. 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) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS) 2008-12 https://hal.science/hal-00400418 https://hal.science/hal-00400418/document https://hal.science/hal-00400418/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Optimal%20Surface%20Salinity%20Perturbations%20of%20the%20Meridional%20Overturning%20and%20Heat%20Transport%20in%20a%20Global%20Ocean%20General%20Circulation%20Model.pdf https://doi.org/10.1175/2008JPO3875.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/2008JPO3875.1 hal-00400418 https://hal.science/hal-00400418 https://hal.science/hal-00400418/document https://hal.science/hal-00400418/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Optimal%20Surface%20Salinity%20Perturbations%20of%20the%20Meridional%20Overturning%20and%20Heat%20Transport%20in%20a%20Global%20Ocean%20General%20Circulation%20Model.pdf doi:10.1175/2008JPO3875.1 IRD: fdi:010045301 WOS: 000261921200008 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal.science/hal-00400418 Journal of Physical Oceanography, 2008, 38 (12), pp.2739-2754. ⟨10.1175/2008JPO3875.1⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2008 ftsorbonneuniv https://doi.org/10.1175/2008JPO3875.1 2024-04-25T03:56:49Z International audience Recent observations and modeling studies have stressed the influence of surface salinity perturbations on the North Atlantic circulation over the past few decades. As a step toward the estimation of the sensitivity of the thermohaline circulation to salinity anomalies, optimal initial surface salinity perturbations are computed and described for a realistic mean state of a global ocean general circulation model [Océan Parallélisé (OPA)]; optimality is defined successively with respect to the meridional overturning circulation intensity and the meridional heat transport maximum. Although the system is asymptotically stable, the nonnormality of the dynamics is able to produce a transient growth through an initial stimulation. Optimal perturbations are calculated subject to three constraints: the perturbation applies to surface salinity; the perturbation conserves the global salt content; and the perturbation is normalized, to remove the degeneracy in the linear maximization problem. Maximization using Lagrangian multipliers leads to explicit solutions (rather than eigenvalue problems), involving the integration of the model adjoint for each value to maximize. The most efficient transient growth for the intensity of the meridional overturning circulation appears for a delay of 10.5 yr after the perturbation by the optimal surface salinity anomaly. This optimal growth is induced by an initial anomaly located north of 50°N. In the same way, the most efficient transient growth for the intensity of the meridional heat transport appears for a shorter delay of 2.2 yr after the perturbation by the optimal surface salinity anomaly. This initial optimal perturbation corresponds to a zonal salinity gradient around 24°N. The optimal surface salinity perturbations studied herein yield upper bounds on the intensity of the response in meridional overturning circulation and meridional heat transport. Using typical amplitudes of the Great Salinity Anomalies, the upper bounds for the associated variability ... Article in Journal/Newspaper North Atlantic HAL Sorbonne Université Journal of Physical Oceanography 38 12 2739 2754 |