Spectral characteristics of the response of the meridional overturning circulation to deep water formation
The response of the upper limb of the meridional overturning circulation to the variability of deep-water formation is investigated analytically with a linear, reduced-gravity model in basins of simple geometry. The spectral characteristics of the model response are first derived by prescribing whit...
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
2005
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Online Access: | https://hal.science/hal-00122297 https://hal.science/hal-00122297/document https://hal.science/hal-00122297/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Spectral%20Characteristics%20of%20the%20Response%20of%20the%20Meridional%20Overturning%20Circulation%20to%20Deep-Water%20Formation.pdf https://doi.org/10.1175/JPO2793.1 |
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ftceafr:oai:HAL:hal-00122297v1 |
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Open Polar |
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HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) |
op_collection_id |
ftceafr |
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 Deshayes, Julie Frankignoul, Claude Spectral characteristics of the response of the meridional overturning circulation to deep water formation |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
The response of the upper limb of the meridional overturning circulation to the variability of deep-water formation is investigated analytically with a linear, reduced-gravity model in basins of simple geometry. The spectral characteristics of the model response are first derived by prescribing white-noise fluctuations in the meridional transport at the northern boundary. Although low-frequency basin modes are solutions to the eigenproblem, they are too dissipative to be significantly excited by the boundary forcing, and the thermocline depth response has a red spectrum with no prevailing time scale other than that of a high-frequency equatorial mode, only flattening at the millennial time scale because of vertical diffusivity. The meridional transport is asymmetric about the equator because the northern part of the basin is directly influenced by the boundary forcing while the southern part is mostly set in motion by long Rossby waves. This results in the equator acting as a low-pass filter for the Southern Hemisphere, which clarifies the so-called buffering effect of the equator. In a basin connected by a southern circumpolar channel, the thermocline depth and the transport spectra are redder than in the forced basin and, when a somewhat more realistic stochastic forcing derived from general circulation model simulations is considered, the variability is strongly reduced at high frequency. The linear model qualitatively explains several features of the low-frequency variability of the meridional overturning circulation in climate models, such as its red spectrum and its larger intensity in the North Atlantic Ocean. |
author2 |
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) |
format |
Article in Journal/Newspaper |
author |
Deshayes, Julie Frankignoul, Claude |
author_facet |
Deshayes, Julie Frankignoul, Claude |
author_sort |
Deshayes, Julie |
title |
Spectral characteristics of the response of the meridional overturning circulation to deep water formation |
title_short |
Spectral characteristics of the response of the meridional overturning circulation to deep water formation |
title_full |
Spectral characteristics of the response of the meridional overturning circulation to deep water formation |
title_fullStr |
Spectral characteristics of the response of the meridional overturning circulation to deep water formation |
title_full_unstemmed |
Spectral characteristics of the response of the meridional overturning circulation to deep water formation |
title_sort |
spectral characteristics of the response of the meridional overturning circulation to deep water formation |
publisher |
HAL CCSD |
publishDate |
2005 |
url |
https://hal.science/hal-00122297 https://hal.science/hal-00122297/document https://hal.science/hal-00122297/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Spectral%20Characteristics%20of%20the%20Response%20of%20the%20Meridional%20Overturning%20Circulation%20to%20Deep-Water%20Formation.pdf https://doi.org/10.1175/JPO2793.1 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal.science/hal-00122297 Journal of Physical Oceanography, 2005, 35 (10), pp.1813-1825. ⟨10.1175/JPO2793.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JPO2793.1 hal-00122297 https://hal.science/hal-00122297 https://hal.science/hal-00122297/document https://hal.science/hal-00122297/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Spectral%20Characteristics%20of%20the%20Response%20of%20the%20Meridional%20Overturning%20Circulation%20to%20Deep-Water%20Formation.pdf doi:10.1175/JPO2793.1 IRD: PAR00000638 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JPO2793.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
35 |
container_issue |
10 |
container_start_page |
1813 |
op_container_end_page |
1825 |
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1810464163735011328 |
spelling |
ftceafr:oai:HAL:hal-00122297v1 2024-09-15T18:23:53+00:00 Spectral characteristics of the response of the meridional overturning circulation to deep water formation Deshayes, Julie Frankignoul, Claude 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) 2005 https://hal.science/hal-00122297 https://hal.science/hal-00122297/document https://hal.science/hal-00122297/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Spectral%20Characteristics%20of%20the%20Response%20of%20the%20Meridional%20Overturning%20Circulation%20to%20Deep-Water%20Formation.pdf https://doi.org/10.1175/JPO2793.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JPO2793.1 hal-00122297 https://hal.science/hal-00122297 https://hal.science/hal-00122297/document https://hal.science/hal-00122297/file/%5B15200485%20-%20Journal%20of%20Physical%20Oceanography%5D%20Spectral%20Characteristics%20of%20the%20Response%20of%20the%20Meridional%20Overturning%20Circulation%20to%20Deep-Water%20Formation.pdf doi:10.1175/JPO2793.1 IRD: PAR00000638 info:eu-repo/semantics/OpenAccess ISSN: 0022-3670 EISSN: 1520-0485 Journal of Physical Oceanography https://hal.science/hal-00122297 Journal of Physical Oceanography, 2005, 35 (10), pp.1813-1825. ⟨10.1175/JPO2793.1⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2005 ftceafr https://doi.org/10.1175/JPO2793.1 2024-07-22T13:16:28Z The response of the upper limb of the meridional overturning circulation to the variability of deep-water formation is investigated analytically with a linear, reduced-gravity model in basins of simple geometry. The spectral characteristics of the model response are first derived by prescribing white-noise fluctuations in the meridional transport at the northern boundary. Although low-frequency basin modes are solutions to the eigenproblem, they are too dissipative to be significantly excited by the boundary forcing, and the thermocline depth response has a red spectrum with no prevailing time scale other than that of a high-frequency equatorial mode, only flattening at the millennial time scale because of vertical diffusivity. The meridional transport is asymmetric about the equator because the northern part of the basin is directly influenced by the boundary forcing while the southern part is mostly set in motion by long Rossby waves. This results in the equator acting as a low-pass filter for the Southern Hemisphere, which clarifies the so-called buffering effect of the equator. In a basin connected by a southern circumpolar channel, the thermocline depth and the transport spectra are redder than in the forced basin and, when a somewhat more realistic stochastic forcing derived from general circulation model simulations is considered, the variability is strongly reduced at high frequency. The linear model qualitatively explains several features of the low-frequency variability of the meridional overturning circulation in climate models, such as its red spectrum and its larger intensity in the North Atlantic Ocean. Article in Journal/Newspaper North Atlantic HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) Journal of Physical Oceanography 35 10 1813 1825 |