Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records
International audience The Meridional Overturning Circulation (AMOC) is believed to have played a key role in climate variability over the Holocene, but the reconstruction of its variations remains limited by inconsistencies among different proxy records used. To circumvent this issue, we propose a...
Published in: | Global and Planetary Change |
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ftunivnantes:oai:HAL:hal-01901183v1 2023-05-15T17:30:41+02:00 Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records Ayache, Mohamed Swingedouw, Didier Mary, Yannick Eynaud, Frédérique Colin, Christophe Environnements et Paléoenvironnements OCéaniques (EPOC) Observatoire aquitain des sciences de l'univers (OASU) Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) 2018-11 https://hal.science/hal-01901183 https://doi.org/10.1016/j.gloplacha.2018.08.016 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.gloplacha.2018.08.016 hal-01901183 https://hal.science/hal-01901183 doi:10.1016/j.gloplacha.2018.08.016 ISSN: 0921-8181 Global and Planetary Change https://hal.science/hal-01901183 Global and Planetary Change, 2018, 170, pp.172 - 189. ⟨10.1016/j.gloplacha.2018.08.016⟩ [SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2018 ftunivnantes https://doi.org/10.1016/j.gloplacha.2018.08.016 2023-02-08T08:17:46Z International audience The Meridional Overturning Circulation (AMOC) is believed to have played a key role in climate variability over the Holocene, but the reconstruction of its variations remains limited by inconsistencies among different proxy records used. To circumvent this issue, we propose a new statistical method to reconstruct the AMOC variations based on multiple sources of information, i.e. 22 proxy records of annual Sea Surface Temperature (SST) compiled in the North Atlantic and covering the Holocene (HAMOC database). Our approach consists of isolating the main variability modes hidden in the Atlantic Ocean through principal component analysis (PCA) and then evaluating their link with the AMOC. To estimate the skill of our method, we use a pseudo-proxy approach applied to observational SST data covering the period 1870–2010, as well as simulations from a comprehensive climate model (IPSL-CM5A-LR) where the AMOC variations are known. In instrumental observations and most of the model simulations, the first mode of SST variations from the PCA analysis over the North Atlantic can be related with the external radiative forcing, while the second mode is reminiscent of the AMOC variability and of its signature on SST. When computed over the Holocene period using the HAMOC database, the first mode is indeed well correlated with the insolation changes, marked by a general cooling of the Northern Atlantic from 9 thousand years ago (ka). The second mode, that we consider here as a reconstruction of standardized AMOC variations following the pseudo-proxy analysis in the model simulations and in the observations, is in general agreement with a few independent reconstructions of the deep branch of the AMOC recorded in the North Atlantic. Based on this new AMOC index reconstruction, we highlight that the Early Holocene may have been associated with an AMOC enhancement, followed by a general weakening trend from around 6–7 ka up to 2 ka, in line with the major hydro-dynamical re-organization which occurred in ... Article in Journal/Newspaper North Atlantic Université de Nantes: HAL-UNIV-NANTES Global and Planetary Change 170 172 189 |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
[SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Ayache, Mohamed Swingedouw, Didier Mary, Yannick Eynaud, Frédérique Colin, Christophe Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records |
topic_facet |
[SDU]Sciences of the Universe [physics] [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience The Meridional Overturning Circulation (AMOC) is believed to have played a key role in climate variability over the Holocene, but the reconstruction of its variations remains limited by inconsistencies among different proxy records used. To circumvent this issue, we propose a new statistical method to reconstruct the AMOC variations based on multiple sources of information, i.e. 22 proxy records of annual Sea Surface Temperature (SST) compiled in the North Atlantic and covering the Holocene (HAMOC database). Our approach consists of isolating the main variability modes hidden in the Atlantic Ocean through principal component analysis (PCA) and then evaluating their link with the AMOC. To estimate the skill of our method, we use a pseudo-proxy approach applied to observational SST data covering the period 1870–2010, as well as simulations from a comprehensive climate model (IPSL-CM5A-LR) where the AMOC variations are known. In instrumental observations and most of the model simulations, the first mode of SST variations from the PCA analysis over the North Atlantic can be related with the external radiative forcing, while the second mode is reminiscent of the AMOC variability and of its signature on SST. When computed over the Holocene period using the HAMOC database, the first mode is indeed well correlated with the insolation changes, marked by a general cooling of the Northern Atlantic from 9 thousand years ago (ka). The second mode, that we consider here as a reconstruction of standardized AMOC variations following the pseudo-proxy analysis in the model simulations and in the observations, is in general agreement with a few independent reconstructions of the deep branch of the AMOC recorded in the North Atlantic. Based on this new AMOC index reconstruction, we highlight that the Early Holocene may have been associated with an AMOC enhancement, followed by a general weakening trend from around 6–7 ka up to 2 ka, in line with the major hydro-dynamical re-organization which occurred in ... |
author2 |
Environnements et Paléoenvironnements OCéaniques (EPOC) Observatoire aquitain des sciences de l'univers (OASU) Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Ayache, Mohamed Swingedouw, Didier Mary, Yannick Eynaud, Frédérique Colin, Christophe |
author_facet |
Ayache, Mohamed Swingedouw, Didier Mary, Yannick Eynaud, Frédérique Colin, Christophe |
author_sort |
Ayache, Mohamed |
title |
Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records |
title_short |
Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records |
title_full |
Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records |
title_fullStr |
Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records |
title_full_unstemmed |
Multi-centennial variability of the AMOC over the Holocene: A new reconstruction based on multiple proxy-derived SST records |
title_sort |
multi-centennial variability of the amoc over the holocene: a new reconstruction based on multiple proxy-derived sst records |
publisher |
HAL CCSD |
publishDate |
2018 |
url |
https://hal.science/hal-01901183 https://doi.org/10.1016/j.gloplacha.2018.08.016 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0921-8181 Global and Planetary Change https://hal.science/hal-01901183 Global and Planetary Change, 2018, 170, pp.172 - 189. ⟨10.1016/j.gloplacha.2018.08.016⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.gloplacha.2018.08.016 hal-01901183 https://hal.science/hal-01901183 doi:10.1016/j.gloplacha.2018.08.016 |
op_doi |
https://doi.org/10.1016/j.gloplacha.2018.08.016 |
container_title |
Global and Planetary Change |
container_volume |
170 |
container_start_page |
172 |
op_container_end_page |
189 |
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1766127562345414656 |