Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean.
By taking up large amounts of atmospheric CO2, the Southern Ocean helps to regulate the climate system. Southern Ocean carbon sink is poorly constrained, in part because data coverage is sparse and also because ocean models that have been used in such assessments fail to explicitly resolve key physi...
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Other Authors: | , , , , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2011
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Subjects: | |
Online Access: | https://theses.hal.science/tel-00679918 https://theses.hal.science/tel-00679918/document https://theses.hal.science/tel-00679918/file/24331_DUFOUR_2011_archivage1.pdf |
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ftceafr:oai:HAL:tel-00679918v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) |
op_collection_id |
ftceafr |
language |
French |
topic |
Southern Ocean Air-sea CO2 fluxes Eddies Southern Annular Mode Numerical dynamics-biogeochemistry model Océan Austral Flux air-mer de CO2 Tourbillons Mode Annulaire Austral Modèle numérique dynamique-biogéochimie [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Southern Ocean Air-sea CO2 fluxes Eddies Southern Annular Mode Numerical dynamics-biogeochemistry model Océan Austral Flux air-mer de CO2 Tourbillons Mode Annulaire Austral Modèle numérique dynamique-biogéochimie [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Dufour, Carolina Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. |
topic_facet |
Southern Ocean Air-sea CO2 fluxes Eddies Southern Annular Mode Numerical dynamics-biogeochemistry model Océan Austral Flux air-mer de CO2 Tourbillons Mode Annulaire Austral Modèle numérique dynamique-biogéochimie [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
By taking up large amounts of atmospheric CO2, the Southern Ocean helps to regulate the climate system. Southern Ocean carbon sink is poorly constrained, in part because data coverage is sparse and also because ocean models that have been used in such assessments fail to explicitly resolve key physical features such as mesoscale eddies. In recent decades, the growth of the Southern Ocean carbon sink may have been partly counteracted due to a loss of natural CO2 from the ocean driven by an intensification of westerlies, related to a positive trend in the Southern Annular Mode (SAM). This thesis focuses on documenting and understanding recent spatial and temporal variability of air-sea CO2 fluxes in the Southern Ocean. Sensitivity to positive phases of the SAM are tested by making simulations with a regional model of the Southern Ocean (south of 30°S) that couples biogeochemistry to the dynamics, is forced by atmosphere reanalysis data, and partially resolves the mesoscale. The resulting response of Southern Ocean CO2 fluxes to the SAM is dominated by a strong CO2 efflux to the atmosphere from the Antarctic Zone due to an increase in surface dissolved inorganic carbon (DIC). This increase is driven by the mixed-layer dynamics and is supplied by a meridional transport of DIC, a competition between the wind-driven circulation and the standing eddy-induced circulation. This work discusses the effect of increasing model resolution on simulated air-sea CO2 fluxes. L'océan Austral joue un rôle crucial dans la régulation du système climatique en absorbant de grandes quantités de CO2 atmosphérique. Toutefois de nombreuses incertitudes demeurent quant à l'évolution récente du puits de carbone austral notamment en raison du manque d'observations et des lacunes des modèles océaniques dans la représentation de processus dynamiques comme les tourbillons. Depuis quelques décennies notamment, l'efficacité du puits de carbone austral diminuerait en raison d'une intensification des vents liée à une tendance positive du Mode ... |
author2 |
Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Université de Grenoble Bernard Barnier Marion Gehlen Julien Le Sommer James Wilder Orr |
format |
Doctoral or Postdoctoral Thesis |
author |
Dufour, Carolina |
author_facet |
Dufour, Carolina |
author_sort |
Dufour, Carolina |
title |
Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. |
title_short |
Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. |
title_full |
Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. |
title_fullStr |
Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. |
title_full_unstemmed |
Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. |
title_sort |
impact of oceanic eddy activity on the variability of co2 air-sea fluxes in the southern ocean. |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://theses.hal.science/tel-00679918 https://theses.hal.science/tel-00679918/document https://theses.hal.science/tel-00679918/file/24331_DUFOUR_2011_archivage1.pdf |
long_lat |
ENVELOPE(139.951,139.951,-66.669,-66.669) |
geographic |
Antarctic Southern Ocean The Antarctic Austral Tourbillons |
geographic_facet |
Antarctic Southern Ocean The Antarctic Austral Tourbillons |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
https://theses.hal.science/tel-00679918 Sciences de la Terre. Université de Grenoble, 2011. Français. ⟨NNT : 2011GRENU040⟩ |
op_relation |
NNT: 2011GRENU040 tel-00679918 https://theses.hal.science/tel-00679918 https://theses.hal.science/tel-00679918/document https://theses.hal.science/tel-00679918/file/24331_DUFOUR_2011_archivage1.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1801374234881032192 |
spelling |
ftceafr:oai:HAL:tel-00679918v1 2024-06-09T07:38:37+00:00 Impact of oceanic eddy activity on the variability of CO2 air-sea fluxes in the Southern Ocean. Rôle des tourbillons océaniques dans la variabilité récente des flux air-mer de CO2 dans l'océan Austral Dufour, Carolina Laboratoire des Écoulements Géophysiques et Industriels Grenoble (LEGI) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Université de Grenoble Bernard Barnier Marion Gehlen Julien Le Sommer James Wilder Orr 2011-12-06 https://theses.hal.science/tel-00679918 https://theses.hal.science/tel-00679918/document https://theses.hal.science/tel-00679918/file/24331_DUFOUR_2011_archivage1.pdf fr fre HAL CCSD NNT: 2011GRENU040 tel-00679918 https://theses.hal.science/tel-00679918 https://theses.hal.science/tel-00679918/document https://theses.hal.science/tel-00679918/file/24331_DUFOUR_2011_archivage1.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00679918 Sciences de la Terre. Université de Grenoble, 2011. Français. ⟨NNT : 2011GRENU040⟩ Southern Ocean Air-sea CO2 fluxes Eddies Southern Annular Mode Numerical dynamics-biogeochemistry model Océan Austral Flux air-mer de CO2 Tourbillons Mode Annulaire Austral Modèle numérique dynamique-biogéochimie [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2011 ftceafr 2024-05-16T12:45:18Z By taking up large amounts of atmospheric CO2, the Southern Ocean helps to regulate the climate system. Southern Ocean carbon sink is poorly constrained, in part because data coverage is sparse and also because ocean models that have been used in such assessments fail to explicitly resolve key physical features such as mesoscale eddies. In recent decades, the growth of the Southern Ocean carbon sink may have been partly counteracted due to a loss of natural CO2 from the ocean driven by an intensification of westerlies, related to a positive trend in the Southern Annular Mode (SAM). This thesis focuses on documenting and understanding recent spatial and temporal variability of air-sea CO2 fluxes in the Southern Ocean. Sensitivity to positive phases of the SAM are tested by making simulations with a regional model of the Southern Ocean (south of 30°S) that couples biogeochemistry to the dynamics, is forced by atmosphere reanalysis data, and partially resolves the mesoscale. The resulting response of Southern Ocean CO2 fluxes to the SAM is dominated by a strong CO2 efflux to the atmosphere from the Antarctic Zone due to an increase in surface dissolved inorganic carbon (DIC). This increase is driven by the mixed-layer dynamics and is supplied by a meridional transport of DIC, a competition between the wind-driven circulation and the standing eddy-induced circulation. This work discusses the effect of increasing model resolution on simulated air-sea CO2 fluxes. L'océan Austral joue un rôle crucial dans la régulation du système climatique en absorbant de grandes quantités de CO2 atmosphérique. Toutefois de nombreuses incertitudes demeurent quant à l'évolution récente du puits de carbone austral notamment en raison du manque d'observations et des lacunes des modèles océaniques dans la représentation de processus dynamiques comme les tourbillons. Depuis quelques décennies notamment, l'efficacité du puits de carbone austral diminuerait en raison d'une intensification des vents liée à une tendance positive du Mode ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Southern Ocean HAL-CEA (Commissariat à l'énergie atomique et aux énergies alternatives) Antarctic Southern Ocean The Antarctic Austral Tourbillons ENVELOPE(139.951,139.951,-66.669,-66.669) |