Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn
In the first part of this thesis, we study the influence of the Southern Annular Mode (SAM) onto the Atlantic Meridional Overturning Circulation (AMOC) in a control simulation with the IPSLCM4 model. We show that a positive phase of the SAM, corresponding to an intensification of the Westerlies sout...
Main Author: | |
---|---|
Other Authors: | , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
HAL CCSD
2011
|
Subjects: | |
Online Access: | https://theses.hal.science/tel-00994862 https://theses.hal.science/tel-00994862/document https://theses.hal.science/tel-00994862/file/Thesis_Marini.pdf |
id |
ftinsu:oai:HAL:tel-00994862v1 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
Atlantic Meridional Overturning Circulation Atlantic Multidecadal Oscillation El Nino Southern Oscillation decadal and multidecadal variability Arctic Oscillation Southern Annular Mode Linear Inverse Modeling Volcanic eruptions Circulation Méridienne de renversement Atlantique Oscillation Multidécennale Atlantique El Nino Variabilité décennale Variabilité multidécennale Teleconnections Oscillation Arctique Mode Annulaire Sud Modéle Linéaire Inverse Eruptions volcaniques [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
Atlantic Meridional Overturning Circulation Atlantic Multidecadal Oscillation El Nino Southern Oscillation decadal and multidecadal variability Arctic Oscillation Southern Annular Mode Linear Inverse Modeling Volcanic eruptions Circulation Méridienne de renversement Atlantique Oscillation Multidécennale Atlantique El Nino Variabilité décennale Variabilité multidécennale Teleconnections Oscillation Arctique Mode Annulaire Sud Modéle Linéaire Inverse Eruptions volcaniques [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Marini, Camille Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn |
topic_facet |
Atlantic Meridional Overturning Circulation Atlantic Multidecadal Oscillation El Nino Southern Oscillation decadal and multidecadal variability Arctic Oscillation Southern Annular Mode Linear Inverse Modeling Volcanic eruptions Circulation Méridienne de renversement Atlantique Oscillation Multidécennale Atlantique El Nino Variabilité décennale Variabilité multidécennale Teleconnections Oscillation Arctique Mode Annulaire Sud Modéle Linéaire Inverse Eruptions volcaniques [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
In the first part of this thesis, we study the influence of the Southern Annular Mode (SAM) onto the Atlantic Meridional Overturning Circulation (AMOC) in a control simulation with the IPSLCM4 model. We show that a positive phase of the SAM, corresponding to an intensification of the Westerlies south of 45 ̊S, leads to an acceleration of the AMOC after 8 years, via an atmospheric teleconnection, which is likely to be model-dependent. We also find a link between the SAM and the AMOC at a multidecadal time scale. Positive salt anomalies, created by a positive SAM, enter the South Atlantic from the Drake Passage and, more importantly, via the Aghulas leakage; they propagate northward, eventually reaching the northern North Atlantic where they decrease the vertical stratification and thus increase the AMOC. In the second part of this thesis, we study to what extent the Atlantic Multidecadal Oscillation (AMO) reflects the AMOC fluctuations, and what are the other signals that influence it in natural climate variability conditions and with the external forcings of the 20th century. We use a dynamical filter, based on linear inverse modeling (LIM), to decompose the North Atlantic sea surface temperature (SST) field into a global trend, an El Nino Southern Oscillation-related part (ENSO), a part associated with Pacific decadal variability and a residual. In the historical simulation with the IPSLCM5 climate model, removing the global trend from the AMO with LIM yields to better correlations with the AMOC than removing a linear trend or the global mean SST. We also find that removing the ENSO-related part from the AMO with LIM leads to small changes, and even better correlations with the AMOC. Additionaly removing the signal associated to Pacific decadal variability leads to considerable changes in the AMO, which becomes much less correlated to the AMOC. The robustness of these results is demonstrated by performing the LIM decomposition in control simulations with five different climate models. Besides, the LIM filter is ... |
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) Université Pierre et Marie Curie - Paris VI Claude Frankignoul |
format |
Doctoral or Postdoctoral Thesis |
author |
Marini, Camille |
author_facet |
Marini, Camille |
author_sort |
Marini, Camille |
title |
Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn |
title_short |
Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn |
title_full |
Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn |
title_fullStr |
Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn |
title_full_unstemmed |
Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn |
title_sort |
study of the causes and eff ects of the atlantic meridional overturning circulationn |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://theses.hal.science/tel-00994862 https://theses.hal.science/tel-00994862/document https://theses.hal.science/tel-00994862/file/Thesis_Marini.pdf |
genre |
Arctic Arctique* Drake Passage North Atlantic |
genre_facet |
Arctic Arctique* Drake Passage North Atlantic |
op_source |
https://theses.hal.science/tel-00994862 Ocean, Atmosphere. Université Pierre et Marie Curie - Paris VI, 2011. English. ⟨NNT : ⟩ |
op_relation |
tel-00994862 https://theses.hal.science/tel-00994862 https://theses.hal.science/tel-00994862/document https://theses.hal.science/tel-00994862/file/Thesis_Marini.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1797579408470441984 |
spelling |
ftinsu:oai:HAL:tel-00994862v1 2024-04-28T08:12:34+00:00 Study of the causes and eff ects of the Atlantic Meridional Overturning Circulationn Etude des causes et effets de la circulation méridienne de retournement Atlantique Marini, Camille 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) Université Pierre et Marie Curie - Paris VI Claude Frankignoul 2011-11-28 https://theses.hal.science/tel-00994862 https://theses.hal.science/tel-00994862/document https://theses.hal.science/tel-00994862/file/Thesis_Marini.pdf en eng HAL CCSD tel-00994862 https://theses.hal.science/tel-00994862 https://theses.hal.science/tel-00994862/document https://theses.hal.science/tel-00994862/file/Thesis_Marini.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00994862 Ocean, Atmosphere. Université Pierre et Marie Curie - Paris VI, 2011. English. ⟨NNT : ⟩ Atlantic Meridional Overturning Circulation Atlantic Multidecadal Oscillation El Nino Southern Oscillation decadal and multidecadal variability Arctic Oscillation Southern Annular Mode Linear Inverse Modeling Volcanic eruptions Circulation Méridienne de renversement Atlantique Oscillation Multidécennale Atlantique El Nino Variabilité décennale Variabilité multidécennale Teleconnections Oscillation Arctique Mode Annulaire Sud Modéle Linéaire Inverse Eruptions volcaniques [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/doctoralThesis Theses 2011 ftinsu 2024-04-05T00:20:20Z In the first part of this thesis, we study the influence of the Southern Annular Mode (SAM) onto the Atlantic Meridional Overturning Circulation (AMOC) in a control simulation with the IPSLCM4 model. We show that a positive phase of the SAM, corresponding to an intensification of the Westerlies south of 45 ̊S, leads to an acceleration of the AMOC after 8 years, via an atmospheric teleconnection, which is likely to be model-dependent. We also find a link between the SAM and the AMOC at a multidecadal time scale. Positive salt anomalies, created by a positive SAM, enter the South Atlantic from the Drake Passage and, more importantly, via the Aghulas leakage; they propagate northward, eventually reaching the northern North Atlantic where they decrease the vertical stratification and thus increase the AMOC. In the second part of this thesis, we study to what extent the Atlantic Multidecadal Oscillation (AMO) reflects the AMOC fluctuations, and what are the other signals that influence it in natural climate variability conditions and with the external forcings of the 20th century. We use a dynamical filter, based on linear inverse modeling (LIM), to decompose the North Atlantic sea surface temperature (SST) field into a global trend, an El Nino Southern Oscillation-related part (ENSO), a part associated with Pacific decadal variability and a residual. In the historical simulation with the IPSLCM5 climate model, removing the global trend from the AMO with LIM yields to better correlations with the AMOC than removing a linear trend or the global mean SST. We also find that removing the ENSO-related part from the AMO with LIM leads to small changes, and even better correlations with the AMOC. Additionaly removing the signal associated to Pacific decadal variability leads to considerable changes in the AMO, which becomes much less correlated to the AMOC. The robustness of these results is demonstrated by performing the LIM decomposition in control simulations with five different climate models. Besides, the LIM filter is ... Doctoral or Postdoctoral Thesis Arctic Arctique* Drake Passage North Atlantic Institut national des sciences de l'Univers: HAL-INSU |