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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Other Authors: | , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2019
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Online Access: | https://theses.hal.science/tel-02998433 https://theses.hal.science/tel-02998433/document https://theses.hal.science/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf |
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ftunivbrest:oai:HAL:tel-02998433v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
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 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)-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://theses.hal.science/tel-02998433 https://theses.hal.science/tel-02998433/document https://theses.hal.science/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://theses.hal.science/tel-02998433 Sciences de la Terre. Université de Bretagne occidentale - Brest, 2019. Français. ⟨NNT : 2019BRES0094⟩ |
op_relation |
NNT: 2019BRES0094 tel-02998433 https://theses.hal.science/tel-02998433 https://theses.hal.science/tel-02998433/document https://theses.hal.science/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1790593641584001024 |
spelling |
ftunivbrest:oai:HAL:tel-02998433v1 2024-02-11T09:58:04+01:00 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 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)-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Patrice Klein Pascal Rivière 2019-12-13 https://theses.hal.science/tel-02998433 https://theses.hal.science/tel-02998433/document https://theses.hal.science/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf fr fre HAL CCSD NNT: 2019BRES0094 tel-02998433 https://theses.hal.science/tel-02998433 https://theses.hal.science/tel-02998433/document https://theses.hal.science/tel-02998433/file/These-2019-SML-Oceanographie_physique_et_environnement-SIEGELMAN_Lia.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/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 ftunivbrest 2024-01-23T23:39:35Z 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 Université de Bretagne Occidentale: HAL Antarctic The Antarctic |