Western boundary dynamics and overturning circulation in the Subpolar North Atlantic
The Atlantic Meridional Overturning Circulation (AMOC) is an essential component of the climate system due to its vital role in the global distribution of heat, carbon, and water masses. The downwelling of North Atlantic surface waters connecting the upper and lower AMOC limbs is an essential yet vu...
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2022
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ftccsdartic:oai:HAL:tel-04106197v1 2023-12-17T10:29:23+01:00 Western boundary dynamics and overturning circulation in the Subpolar North Atlantic Dynamique de bord ouest et circulation méridienne verticale dans le gyre Subpolaire de l’Atlantique Nord Liu, Yingjie Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Herlé Mercier Damien Desbruyères 2022-12-19 https://theses.hal.science/tel-04106197 https://theses.hal.science/tel-04106197/document https://theses.hal.science/tel-04106197/file/These-2022-SML-Oceanographie_physique_et_environnement-LIU_Yingjie.pdf en eng HAL CCSD NNT: 2022BRES0115 tel-04106197 https://theses.hal.science/tel-04106197 https://theses.hal.science/tel-04106197/document https://theses.hal.science/tel-04106197/file/These-2022-SML-Oceanographie_physique_et_environnement-LIU_Yingjie.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-04106197 Oceanography. Université de Bretagne occidentale - Brest, 2022. English. ⟨NNT : 2022BRES0115⟩ AMOC Subpolar Gyre Vertical Transport Observations Gyre subpolaire Transport vertical [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/doctoralThesis Theses 2022 ftccsdartic 2023-11-18T23:48:11Z The Atlantic Meridional Overturning Circulation (AMOC) is an essential component of the climate system due to its vital role in the global distribution of heat, carbon, and water masses. The downwelling of North Atlantic surface waters connecting the upper and lower AMOC limbs is an essential yet vulnerable partof this global circulation. This downwelling partly occurs along continental boundaries. This dissertation presents an extended observational investigation on the quantification of Eulerianmean downwelling along the continental slopes of the North Atlantic subpolar gyre (SPG) and an examination of the underlying mechanisms, with an emphasis on the role of mesoscale eddies. A volume budget of the SPG boundary reveals a total Eulerian-mean (2002-2019) downwelling of -4.41±0.96 Sv at 1300 m depth between Denmark Strait and Flemish Cap, with the barotropic transport (BT) contributing 2.66±0.40 Sv and the baroclinic transport (BC) contributing 1.75±0.43 Sv. To investigate the processes that cause the BC boundary downwelling, i.e., the boundary heat loss and associate along-boundary density gradient, the long-term mean heat budget of the boundary current system is studied. Both lateral heat fluxes, driven by the boundary current/mesoscale eddies, and air-sea heat flux play significant roles in the boundary heat loss. In a Lagrangian framework, it is found that cross-shore eddy propagation generally cools the SPG boundary. La circulation méridienne de retournement de l'Atlantique (AMOC) est une composante essentielle du système climatique en raison de son rôle vital dans la distribution globale de la chaleur, du carbone et des masses d'eau. La descente des eaux de surface de l'Atlantique Nord reliant les branches supérieure et inférieure de l'AMOC est une composante essentielle mais vulnérable de cette circulation globale. Le transport vertical associé se produit en partie le long des frontières continentales. Cette thèse présente une étude observationnelle étendue sur la quantification du « downwelling » ... Doctoral or Postdoctoral Thesis Denmark Strait North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
AMOC Subpolar Gyre Vertical Transport Observations Gyre subpolaire Transport vertical [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
AMOC Subpolar Gyre Vertical Transport Observations Gyre subpolaire Transport vertical [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Liu, Yingjie Western boundary dynamics and overturning circulation in the Subpolar North Atlantic |
topic_facet |
AMOC Subpolar Gyre Vertical Transport Observations Gyre subpolaire Transport vertical [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
The Atlantic Meridional Overturning Circulation (AMOC) is an essential component of the climate system due to its vital role in the global distribution of heat, carbon, and water masses. The downwelling of North Atlantic surface waters connecting the upper and lower AMOC limbs is an essential yet vulnerable partof this global circulation. This downwelling partly occurs along continental boundaries. This dissertation presents an extended observational investigation on the quantification of Eulerianmean downwelling along the continental slopes of the North Atlantic subpolar gyre (SPG) and an examination of the underlying mechanisms, with an emphasis on the role of mesoscale eddies. A volume budget of the SPG boundary reveals a total Eulerian-mean (2002-2019) downwelling of -4.41±0.96 Sv at 1300 m depth between Denmark Strait and Flemish Cap, with the barotropic transport (BT) contributing 2.66±0.40 Sv and the baroclinic transport (BC) contributing 1.75±0.43 Sv. To investigate the processes that cause the BC boundary downwelling, i.e., the boundary heat loss and associate along-boundary density gradient, the long-term mean heat budget of the boundary current system is studied. Both lateral heat fluxes, driven by the boundary current/mesoscale eddies, and air-sea heat flux play significant roles in the boundary heat loss. In a Lagrangian framework, it is found that cross-shore eddy propagation generally cools the SPG boundary. La circulation méridienne de retournement de l'Atlantique (AMOC) est une composante essentielle du système climatique en raison de son rôle vital dans la distribution globale de la chaleur, du carbone et des masses d'eau. La descente des eaux de surface de l'Atlantique Nord reliant les branches supérieure et inférieure de l'AMOC est une composante essentielle mais vulnérable de cette circulation globale. Le transport vertical associé se produit en partie le long des frontières continentales. Cette thèse présente une étude observationnelle étendue sur la quantification du « downwelling » ... |
author2 |
Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Herlé Mercier Damien Desbruyères |
format |
Doctoral or Postdoctoral Thesis |
author |
Liu, Yingjie |
author_facet |
Liu, Yingjie |
author_sort |
Liu, Yingjie |
title |
Western boundary dynamics and overturning circulation in the Subpolar North Atlantic |
title_short |
Western boundary dynamics and overturning circulation in the Subpolar North Atlantic |
title_full |
Western boundary dynamics and overturning circulation in the Subpolar North Atlantic |
title_fullStr |
Western boundary dynamics and overturning circulation in the Subpolar North Atlantic |
title_full_unstemmed |
Western boundary dynamics and overturning circulation in the Subpolar North Atlantic |
title_sort |
western boundary dynamics and overturning circulation in the subpolar north atlantic |
publisher |
HAL CCSD |
publishDate |
2022 |
url |
https://theses.hal.science/tel-04106197 https://theses.hal.science/tel-04106197/document https://theses.hal.science/tel-04106197/file/These-2022-SML-Oceanographie_physique_et_environnement-LIU_Yingjie.pdf |
genre |
Denmark Strait North Atlantic |
genre_facet |
Denmark Strait North Atlantic |
op_source |
https://theses.hal.science/tel-04106197 Oceanography. Université de Bretagne occidentale - Brest, 2022. English. ⟨NNT : 2022BRES0115⟩ |
op_relation |
NNT: 2022BRES0115 tel-04106197 https://theses.hal.science/tel-04106197 https://theses.hal.science/tel-04106197/document https://theses.hal.science/tel-04106197/file/These-2022-SML-Oceanographie_physique_et_environnement-LIU_Yingjie.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1785581761022918656 |