Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales
International audience The low-frequency variability of the Atlantic meridional overturning circulation (AMOC) is investigated from 2, ¼°, and ° global ocean–sea ice simulations, with a specific focus on its internally generated (i.e., “intrinsic”) component. A 327-yr climatological ¼° simulation, d...
Published in: | Journal of Physical Oceanography |
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Main Authors: | , , , , , |
Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2015
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Online Access: | https://hal-insu.archives-ouvertes.fr/insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292/document https://hal-insu.archives-ouvertes.fr/insu-01203292/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Intrinsic%20Variability%20of%20the%20Atlantic%20Meridional%20Overturning%20Circulation%20at%20Interannual-to-Multidecadal%20Time%20Scales.pdf https://doi.org/10.1175/JPO-D-14-0163.1 |
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Open Polar |
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Université de Nantes: HAL-UNIV-NANTES |
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ftunivnantes |
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English |
topic |
[SDE]Environmental Sciences |
spellingShingle |
[SDE]Environmental Sciences Penduff, Thierry Sandy, Grégorio Guillaume, Serazin Molines, Jean-Marc Barnier, Bernard Hirschi, Joël J.-M. Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience The low-frequency variability of the Atlantic meridional overturning circulation (AMOC) is investigated from 2, ¼°, and ° global ocean–sea ice simulations, with a specific focus on its internally generated (i.e., “intrinsic”) component. A 327-yr climatological ¼° simulation, driven by a repeated seasonal cycle (i.e., a forcing devoid of interannual time scales), is shown to spontaneously generate a significant fraction R of the interannual-to-decadal AMOC variance obtained in a 50-yr “fully forced” hindcast (with reanalyzed atmospheric forcing including interannual time scales). This intrinsic variance fraction R slightly depends on whether AMOCs are computed in geopotential or density coordinates, and on the period considered in the climatological simulation, but the following features are quite robust when mesoscale eddies are simulated (at both ¼° and ° resolutions); R barely exceeds 5%–10% in the subpolar gyre but reaches 30%–50% at 34°S, up to 20%–40% near 25°N, and 40%–60% near the Gulf Stream. About 25% of the meridional heat transport interannual variability is attributed to intrinsic processes at 34°S and near the Gulf Stream. Fourier and wavelet spectra, built from the 327-yr ¼° climatological simulation, further indicate that spectral peaks of intrinsic AMOC variability (i) are found at specific frequencies ranging from interannual to multidecadal, (ii) often extend over the whole meridional scale of gyres, (iii) stochastically change throughout these 327 yr, and (iv) sometimes match the spectral peaks found in the fully forced hindcast in the North Atlantic. Intrinsic AMOC variability is also detected at multidecadal time scales, with a marked meridional coherence between 35°S and 25°N (15–30 yr periods) and throughout the whole basin (50–90-yr periods). |
author2 |
Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Penduff, Thierry Sandy, Grégorio Guillaume, Serazin Molines, Jean-Marc Barnier, Bernard Hirschi, Joël J.-M. |
author_facet |
Penduff, Thierry Sandy, Grégorio Guillaume, Serazin Molines, Jean-Marc Barnier, Bernard Hirschi, Joël J.-M. |
author_sort |
Penduff, Thierry |
title |
Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales |
title_short |
Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales |
title_full |
Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales |
title_fullStr |
Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales |
title_full_unstemmed |
Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales |
title_sort |
intrinsic variability of the atlantic meridional overturning circulation at interannual-to-multidecadal time scales |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal-insu.archives-ouvertes.fr/insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292/document https://hal-insu.archives-ouvertes.fr/insu-01203292/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Intrinsic%20Variability%20of%20the%20Atlantic%20Meridional%20Overturning%20Circulation%20at%20Interannual-to-Multidecadal%20Time%20Scales.pdf https://doi.org/10.1175/JPO-D-14-0163.1 |
genre |
North Atlantic Sea ice |
genre_facet |
North Atlantic Sea ice |
op_source |
ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal-insu.archives-ouvertes.fr/insu-01203292 Journal of Physical Oceanography, 2015, 45 (7), pp.1929-1946. ⟨10.1175/JPO-D-14-0163.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JPO-D-14-0163.1 insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292/document https://hal-insu.archives-ouvertes.fr/insu-01203292/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Intrinsic%20Variability%20of%20the%20Atlantic%20Meridional%20Overturning%20Circulation%20at%20Interannual-to-Multidecadal%20Time%20Scales.pdf doi:10.1175/JPO-D-14-0163.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JPO-D-14-0163.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
45 |
container_issue |
7 |
container_start_page |
1929 |
op_container_end_page |
1946 |
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1766134208263094272 |
spelling |
ftunivnantes:oai:HAL:insu-01203292v1 2023-05-15T17:35:09+02:00 Intrinsic Variability of the Atlantic Meridional Overturning Circulation at Interannual-to-Multidecadal Time Scales Penduff, Thierry Sandy, Grégorio Guillaume, Serazin Molines, Jean-Marc Barnier, Bernard Hirschi, Joël J.-M. Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) 2015-07 https://hal-insu.archives-ouvertes.fr/insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292/document https://hal-insu.archives-ouvertes.fr/insu-01203292/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Intrinsic%20Variability%20of%20the%20Atlantic%20Meridional%20Overturning%20Circulation%20at%20Interannual-to-Multidecadal%20Time%20Scales.pdf https://doi.org/10.1175/JPO-D-14-0163.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JPO-D-14-0163.1 insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292 https://hal-insu.archives-ouvertes.fr/insu-01203292/document https://hal-insu.archives-ouvertes.fr/insu-01203292/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Intrinsic%20Variability%20of%20the%20Atlantic%20Meridional%20Overturning%20Circulation%20at%20Interannual-to-Multidecadal%20Time%20Scales.pdf doi:10.1175/JPO-D-14-0163.1 info:eu-repo/semantics/OpenAccess ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal-insu.archives-ouvertes.fr/insu-01203292 Journal of Physical Oceanography, 2015, 45 (7), pp.1929-1946. ⟨10.1175/JPO-D-14-0163.1⟩ [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2015 ftunivnantes https://doi.org/10.1175/JPO-D-14-0163.1 2023-03-01T02:37:38Z International audience The low-frequency variability of the Atlantic meridional overturning circulation (AMOC) is investigated from 2, ¼°, and ° global ocean–sea ice simulations, with a specific focus on its internally generated (i.e., “intrinsic”) component. A 327-yr climatological ¼° simulation, driven by a repeated seasonal cycle (i.e., a forcing devoid of interannual time scales), is shown to spontaneously generate a significant fraction R of the interannual-to-decadal AMOC variance obtained in a 50-yr “fully forced” hindcast (with reanalyzed atmospheric forcing including interannual time scales). This intrinsic variance fraction R slightly depends on whether AMOCs are computed in geopotential or density coordinates, and on the period considered in the climatological simulation, but the following features are quite robust when mesoscale eddies are simulated (at both ¼° and ° resolutions); R barely exceeds 5%–10% in the subpolar gyre but reaches 30%–50% at 34°S, up to 20%–40% near 25°N, and 40%–60% near the Gulf Stream. About 25% of the meridional heat transport interannual variability is attributed to intrinsic processes at 34°S and near the Gulf Stream. Fourier and wavelet spectra, built from the 327-yr ¼° climatological simulation, further indicate that spectral peaks of intrinsic AMOC variability (i) are found at specific frequencies ranging from interannual to multidecadal, (ii) often extend over the whole meridional scale of gyres, (iii) stochastically change throughout these 327 yr, and (iv) sometimes match the spectral peaks found in the fully forced hindcast in the North Atlantic. Intrinsic AMOC variability is also detected at multidecadal time scales, with a marked meridional coherence between 35°S and 25°N (15–30 yr periods) and throughout the whole basin (50–90-yr periods). Article in Journal/Newspaper North Atlantic Sea ice Université de Nantes: HAL-UNIV-NANTES Journal of Physical Oceanography 45 7 1929 1946 |