Ageostrophic dynamics in the ocean interior

The ocean is the largest solar energy collector on Earth. The amount of heat it can store is modulated by its complex circulation, which spans a broad range of spatial scales, from centimeters to thousands of kilometers. This dissertation investigates two types of physical processes: mesoscale eddie...

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Main Author: Siegelman, Lia
Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne occidentale - Brest, Patrice Klein, Pascal Rivière
Format: Doctoral or Postdoctoral Thesis
Language:French
Published: HAL CCSD 2019
Subjects:
Online Access:https://tel.archives-ouvertes.fr/tel-02998433
https://tel.archives-ouvertes.fr/tel-02998433/document
https://tel.archives-ouvertes.fr/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf
id ftccsdartic:oai:HAL:tel-02998433v1
record_format openpolar
institution Open Polar
collection Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe)
op_collection_id ftccsdartic
language French
topic Ageostrophy
Interior ocean
Submesoscale
Instrumented elephant seal
Satellite altimetry
Numerical simulation
Agéostrophie
Océan intérieur
Sous-mésoéchelle
Éléphants de mer instrumentés
Altimètre satellite
Simulation numérique
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
spellingShingle Ageostrophy
Interior ocean
Submesoscale
Instrumented elephant seal
Satellite altimetry
Numerical simulation
Agéostrophie
Océan intérieur
Sous-mésoéchelle
Éléphants de mer instrumentés
Altimètre satellite
Simulation numérique
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Siegelman, Lia
Ageostrophic dynamics in the ocean interior
topic_facet Ageostrophy
Interior ocean
Submesoscale
Instrumented elephant seal
Satellite altimetry
Numerical simulation
Agéostrophie
Océan intérieur
Sous-mésoéchelle
Éléphants de mer instrumentés
Altimètre satellite
Simulation numérique
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
description The ocean is the largest solar energy collector on Earth. The amount of heat it can store is modulated by its complex circulation, which spans a broad range of spatial scales, from centimeters to thousands of kilometers. This dissertation investigates two types of physical processes: mesoscale eddies (100-300 km size) and submesoscale fronts (£ 50 km size). To date, ageostrophic submesoscale motions are thought to be mainly trapped within the ocean surface mixed layer, and to be weak in the ocean interior. This is because, in the classical paradigm, motions below the mixed layer are broadly assumed to be in quasigeostrophic balance, preventing the formation of strong buoyancy gradients at depth. This dissertation introduces a paradigm shift; based on a combination of high-resolution in situ CTD data collected by instrumented elephant seals, satellite observations of sea surface height, and high-resolution model outputs in the Antarctic Circumpolar Current, we show that ageostrophic motions (i) are generated by the backgound mesoscale eddy field via frontogenesis processes, and (ii) are not solely confined to the ocean surface mixed layer but, rather, can extend in the ocean interior down to depths of 1 000 m. Deepreaching ageostrophic fronts are shown to drive an anomalous upward heat transport from the ocean interior back to the surface that is larger than other contributions to vertical heat transport and of comparable magnitude to air-sea fluxes. This effect can potentially alter oceanic heat uptake and will be strongest in eddy-rich regions such as the Antarctic Circumpolar Current, the Kuroshio Extension, and the Gulf Stream, all of which are key players in the climate system. As such, ageostrophic fronts at submesoscale provide an important, yet unexplored, pathway for the transport of heat, chemical and biological tracers, between the ocean interior and the surface, with potential major implications for the biogeochemical and climate systems. L'océan est le plus grand réservoir d'énergie solaire de ...
author2 Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR)
Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM)
Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Université de Bretagne occidentale - Brest
Patrice Klein
Pascal Rivière
format Doctoral or Postdoctoral Thesis
author Siegelman, Lia
author_facet Siegelman, Lia
author_sort Siegelman, Lia
title Ageostrophic dynamics in the ocean interior
title_short Ageostrophic dynamics in the ocean interior
title_full Ageostrophic dynamics in the ocean interior
title_fullStr Ageostrophic dynamics in the ocean interior
title_full_unstemmed Ageostrophic dynamics in the ocean interior
title_sort ageostrophic dynamics in the ocean interior
publisher HAL CCSD
publishDate 2019
url https://tel.archives-ouvertes.fr/tel-02998433
https://tel.archives-ouvertes.fr/tel-02998433/document
https://tel.archives-ouvertes.fr/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf
geographic Antarctic
The Antarctic
geographic_facet Antarctic
The Antarctic
genre Antarc*
Antarctic
Elephant Seal
Elephant Seals
genre_facet Antarc*
Antarctic
Elephant Seal
Elephant Seals
op_source https://tel.archives-ouvertes.fr/tel-02998433
Sciences de la Terre. Université de Bretagne occidentale - Brest, 2019. Français. ⟨NNT : 2019BRES0094⟩
op_relation NNT: 2019BRES0094
tel-02998433
https://tel.archives-ouvertes.fr/tel-02998433
https://tel.archives-ouvertes.fr/tel-02998433/document
https://tel.archives-ouvertes.fr/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf
op_rights info:eu-repo/semantics/OpenAccess
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spelling ftccsdartic:oai:HAL:tel-02998433v1 2023-05-15T13:49:24+02:00 Ageostrophic dynamics in the ocean interior Dynamique agéostrophique dans l'océan intérieur Siegelman, Lia Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Patrice Klein Pascal Rivière 2019-12-13 https://tel.archives-ouvertes.fr/tel-02998433 https://tel.archives-ouvertes.fr/tel-02998433/document https://tel.archives-ouvertes.fr/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf fr fre HAL CCSD NNT: 2019BRES0094 tel-02998433 https://tel.archives-ouvertes.fr/tel-02998433 https://tel.archives-ouvertes.fr/tel-02998433/document https://tel.archives-ouvertes.fr/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf info:eu-repo/semantics/OpenAccess https://tel.archives-ouvertes.fr/tel-02998433 Sciences de la Terre. Université de Bretagne occidentale - Brest, 2019. Français. ⟨NNT : 2019BRES0094⟩ Ageostrophy Interior ocean Submesoscale Instrumented elephant seal Satellite altimetry Numerical simulation Agéostrophie Océan intérieur Sous-mésoéchelle Éléphants de mer instrumentés Altimètre satellite Simulation numérique [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2019 ftccsdartic 2021-12-19T00:47:54Z The ocean is the largest solar energy collector on Earth. The amount of heat it can store is modulated by its complex circulation, which spans a broad range of spatial scales, from centimeters to thousands of kilometers. This dissertation investigates two types of physical processes: mesoscale eddies (100-300 km size) and submesoscale fronts (£ 50 km size). To date, ageostrophic submesoscale motions are thought to be mainly trapped within the ocean surface mixed layer, and to be weak in the ocean interior. This is because, in the classical paradigm, motions below the mixed layer are broadly assumed to be in quasigeostrophic balance, preventing the formation of strong buoyancy gradients at depth. This dissertation introduces a paradigm shift; based on a combination of high-resolution in situ CTD data collected by instrumented elephant seals, satellite observations of sea surface height, and high-resolution model outputs in the Antarctic Circumpolar Current, we show that ageostrophic motions (i) are generated by the backgound mesoscale eddy field via frontogenesis processes, and (ii) are not solely confined to the ocean surface mixed layer but, rather, can extend in the ocean interior down to depths of 1 000 m. Deepreaching ageostrophic fronts are shown to drive an anomalous upward heat transport from the ocean interior back to the surface that is larger than other contributions to vertical heat transport and of comparable magnitude to air-sea fluxes. This effect can potentially alter oceanic heat uptake and will be strongest in eddy-rich regions such as the Antarctic Circumpolar Current, the Kuroshio Extension, and the Gulf Stream, all of which are key players in the climate system. As such, ageostrophic fronts at submesoscale provide an important, yet unexplored, pathway for the transport of heat, chemical and biological tracers, between the ocean interior and the surface, with potential major implications for the biogeochemical and climate systems. L'océan est le plus grand réservoir d'énergie solaire de ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Elephant Seal Elephant Seals Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic The Antarctic