Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state
International audience The origin and bifurcation structure of abrupt millennial-scale climate transitions under steady external solar forcing and in the absence of atmospheric synoptic variability is studied by means of a global coupled model of intermediate complexity. We show that the origin of D...
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ftunivbrest:oai:HAL:hal-00715161v1 2023-12-17T10:29:20+01:00 Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state Arzel, Olivier England, Matthew H. Colin de Verdiere, Alain Huck, Thierry 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) Climate Change Research Centre Sydney (CCRC) University of New South Wales Sydney (UNSW) 2012 https://hal.science/hal-00715161 https://doi.org/10.1007/s00382-011-1117-y en eng HAL CCSD Springer Verlag info:eu-repo/semantics/altIdentifier/doi/10.1007/s00382-011-1117-y hal-00715161 https://hal.science/hal-00715161 doi:10.1007/s00382-011-1117-y ISSN: 0930-7575 EISSN: 1432-0894 Climate Dynamics https://hal.science/hal-00715161 Climate Dynamics, 2012, 39 (1-2), pp.259-275. ⟨10.1007/s00382-011-1117-y⟩ Millennial and interdecadal variability paleoclimate Dansgaard-Oeschger events Atlantic meridional overturning circulation [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2012 ftunivbrest https://doi.org/10.1007/s00382-011-1117-y 2023-11-21T23:36:28Z International audience The origin and bifurcation structure of abrupt millennial-scale climate transitions under steady external solar forcing and in the absence of atmospheric synoptic variability is studied by means of a global coupled model of intermediate complexity. We show that the origin of Dansgaard-Oeschger type oscillations in the model is caused by the weaker northward oceanic heat transport in the Atlantic basin. This is in agreement with previous studies realized with much simpler models, based on highly idealized geometries and simplified physics. The existence of abrupt millennial-scale climate transitions during glacial times can therefore be interpreted as a consequence of the weakening of the negative temperature-advection feedback. This is confirmed through a series of numerical experiments designed to explore the sensitivity of the bifurcation structure of the Atlantic meridional overturning circulation to increased atmospheric CO2 levels under glacial boundary conditions. Contrasting with the cold, stadial, phases of millennial oscillations, we also show the emergence of strong interdecadal variability in the North Atlantic sector during warm interstadials. The instability driving these interdecadal-interstadial oscillations is shown to be identical to that found in ocean-only models forced by fixed surface buoyancy fluxes, that is, a large-scale baroclinic instability developing in the vicinity of the western boundary current in the North Atlantic. Comparisons with modern observations further suggest a physical mechanism similar to that driving the 30-40 years time scale associated with the Atlantic multidecadal oscillation. Article in Journal/Newspaper Dansgaard-Oeschger events North Atlantic Université de Bretagne Occidentale: HAL Climate Dynamics 39 1-2 259 275 |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
language |
English |
topic |
Millennial and interdecadal variability paleoclimate Dansgaard-Oeschger events Atlantic meridional overturning circulation [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Millennial and interdecadal variability paleoclimate Dansgaard-Oeschger events Atlantic meridional overturning circulation [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Arzel, Olivier England, Matthew H. Colin de Verdiere, Alain Huck, Thierry Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
topic_facet |
Millennial and interdecadal variability paleoclimate Dansgaard-Oeschger events Atlantic meridional overturning circulation [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience The origin and bifurcation structure of abrupt millennial-scale climate transitions under steady external solar forcing and in the absence of atmospheric synoptic variability is studied by means of a global coupled model of intermediate complexity. We show that the origin of Dansgaard-Oeschger type oscillations in the model is caused by the weaker northward oceanic heat transport in the Atlantic basin. This is in agreement with previous studies realized with much simpler models, based on highly idealized geometries and simplified physics. The existence of abrupt millennial-scale climate transitions during glacial times can therefore be interpreted as a consequence of the weakening of the negative temperature-advection feedback. This is confirmed through a series of numerical experiments designed to explore the sensitivity of the bifurcation structure of the Atlantic meridional overturning circulation to increased atmospheric CO2 levels under glacial boundary conditions. Contrasting with the cold, stadial, phases of millennial oscillations, we also show the emergence of strong interdecadal variability in the North Atlantic sector during warm interstadials. The instability driving these interdecadal-interstadial oscillations is shown to be identical to that found in ocean-only models forced by fixed surface buoyancy fluxes, that is, a large-scale baroclinic instability developing in the vicinity of the western boundary current in the North Atlantic. Comparisons with modern observations further suggest a physical mechanism similar to that driving the 30-40 years time scale associated with the Atlantic multidecadal oscillation. |
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) Climate Change Research Centre Sydney (CCRC) University of New South Wales Sydney (UNSW) |
format |
Article in Journal/Newspaper |
author |
Arzel, Olivier England, Matthew H. Colin de Verdiere, Alain Huck, Thierry |
author_facet |
Arzel, Olivier England, Matthew H. Colin de Verdiere, Alain Huck, Thierry |
author_sort |
Arzel, Olivier |
title |
Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
title_short |
Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
title_full |
Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
title_fullStr |
Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
title_full_unstemmed |
Abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
title_sort |
abrupt millennial variability and interdecadal-interstadial oscillations in a global coupled model: sensitivity to the background climate state |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://hal.science/hal-00715161 https://doi.org/10.1007/s00382-011-1117-y |
genre |
Dansgaard-Oeschger events North Atlantic |
genre_facet |
Dansgaard-Oeschger events North Atlantic |
op_source |
ISSN: 0930-7575 EISSN: 1432-0894 Climate Dynamics https://hal.science/hal-00715161 Climate Dynamics, 2012, 39 (1-2), pp.259-275. ⟨10.1007/s00382-011-1117-y⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1007/s00382-011-1117-y hal-00715161 https://hal.science/hal-00715161 doi:10.1007/s00382-011-1117-y |
op_doi |
https://doi.org/10.1007/s00382-011-1117-y |
container_title |
Climate Dynamics |
container_volume |
39 |
container_issue |
1-2 |
container_start_page |
259 |
op_container_end_page |
275 |
_version_ |
1785581695916834816 |