Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability
International audience The first in situ continuous full-water-column observations of the eastern boundary currents (EBCs) at 34.5°S in the South Atlantic are obtained using 23 months of data from a line of Current and Pressure recording Inverted Echo Sounders (CPIES) spanning the Cape Basin. The CP...
Published in: | Journal of Geophysical Research: Oceans |
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Main Authors: | , , , , , , , , , , , , |
Other Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2019
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Subjects: | |
Online Access: | https://insu.hal.science/insu-03683206 https://insu.hal.science/insu-03683206/document https://insu.hal.science/insu-03683206/file/61644.pdf https://doi.org/10.1029/2018JC014554 |
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Open Polar |
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HAL Sorbonne Université |
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English |
topic |
[SDU]Sciences of the Universe [physics] [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
[SDU]Sciences of the Universe [physics] [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Kersalé, Marion Perez, Renellys C. Speich, Sabrina Meinen, Christopher S. Lamont, Tarron Le Hénaff, Matthieu van den Berg, Marcel A. Majumder, Sudip Ansorge, Isabelle J. Dong, Shenfu Schmid, Claudia Terre, Thierry Garzoli, Silvia L. Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability |
topic_facet |
[SDU]Sciences of the Universe [physics] [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience The first in situ continuous full-water-column observations of the eastern boundary currents (EBCs) at 34.5°S in the South Atlantic are obtained using 23 months of data from a line of Current and Pressure recording Inverted Echo Sounders (CPIES) spanning the Cape Basin. The CPIES are used to evaluate the mean structure of the EBC, the associated water masses, and the volume transport variability. The estimated northward time-mean Benguela Current absolute geostrophic transport is 24 Sv, with a temporal standard deviation of 17 Sv. Beneath this current the time-mean transport is southward, indicating the presence of a deep-EBC (DEBC), with a time-mean transport of 12 Sv, and a standard deviation of 17 Sv. Offshore of these currents, the shallow and deep flows are more variable with weak time means, likely influenced by Agulhas Rings transiting through the region. Hydrographic data collected along the CPIES line demonstrate that the DEBC is carrying recently ventilated North Atlantic Deep Water, as it flows along the continental slope. This is consistent with a previously hypothesized interior pathway bringing recently ventilated North Atlantic Deep Water from the Deep Western Boundary Current across the Atlantic to the Cape Basin. The observations further indicate that much of the DEBC must recirculate within the basin. Spectral analyses of the shallow and deep EBC transport time series demonstrate that the strongest variability occurs on timescales ranging from 30 to 90 days, associated with the propagation of Agulhas Rings. |
author2 |
Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X) Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) 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) |
format |
Article in Journal/Newspaper |
author |
Kersalé, Marion Perez, Renellys C. Speich, Sabrina Meinen, Christopher S. Lamont, Tarron Le Hénaff, Matthieu van den Berg, Marcel A. Majumder, Sudip Ansorge, Isabelle J. Dong, Shenfu Schmid, Claudia Terre, Thierry Garzoli, Silvia L. |
author_facet |
Kersalé, Marion Perez, Renellys C. Speich, Sabrina Meinen, Christopher S. Lamont, Tarron Le Hénaff, Matthieu van den Berg, Marcel A. Majumder, Sudip Ansorge, Isabelle J. Dong, Shenfu Schmid, Claudia Terre, Thierry Garzoli, Silvia L. |
author_sort |
Kersalé, Marion |
title |
Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability |
title_short |
Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability |
title_full |
Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability |
title_fullStr |
Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability |
title_full_unstemmed |
Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability |
title_sort |
shallow and deep eastern boundary currents in the south atlantic at 34.5°s: mean structure and variability |
publisher |
HAL CCSD |
publishDate |
2019 |
url |
https://insu.hal.science/insu-03683206 https://insu.hal.science/insu-03683206/document https://insu.hal.science/insu-03683206/file/61644.pdf https://doi.org/10.1029/2018JC014554 |
genre |
North Atlantic Deep Water North Atlantic |
genre_facet |
North Atlantic Deep Water North Atlantic |
op_source |
ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://insu.hal.science/insu-03683206 Journal of Geophysical Research. Oceans, 2019, 124, pp.1634-1659. ⟨10.1029/2018JC014554⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2018JC014554 insu-03683206 https://insu.hal.science/insu-03683206 https://insu.hal.science/insu-03683206/document https://insu.hal.science/insu-03683206/file/61644.pdf BIBCODE: 2019JGRC.124.1634K doi:10.1029/2018JC014554 |
op_rights |
http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2018JC014554 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
124 |
container_issue |
3 |
container_start_page |
1634 |
op_container_end_page |
1659 |
_version_ |
1810459083707252736 |
spelling |
ftsorbonneuniv:oai:HAL:insu-03683206v1 2024-09-15T18:20:41+00:00 Shallow and Deep Eastern Boundary Currents in the South Atlantic at 34.5°S: Mean Structure and Variability Kersalé, Marion Perez, Renellys C. Speich, Sabrina Meinen, Christopher S. Lamont, Tarron Le Hénaff, Matthieu van den Berg, Marcel A. Majumder, Sudip Ansorge, Isabelle J. Dong, Shenfu Schmid, Claudia Terre, Thierry Garzoli, Silvia L. Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X) Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) 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) 2019 https://insu.hal.science/insu-03683206 https://insu.hal.science/insu-03683206/document https://insu.hal.science/insu-03683206/file/61644.pdf https://doi.org/10.1029/2018JC014554 en eng HAL CCSD Wiley-Blackwell info:eu-repo/semantics/altIdentifier/doi/10.1029/2018JC014554 insu-03683206 https://insu.hal.science/insu-03683206 https://insu.hal.science/insu-03683206/document https://insu.hal.science/insu-03683206/file/61644.pdf BIBCODE: 2019JGRC.124.1634K doi:10.1029/2018JC014554 http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://insu.hal.science/insu-03683206 Journal of Geophysical Research. Oceans, 2019, 124, pp.1634-1659. ⟨10.1029/2018JC014554⟩ [SDU]Sciences of the Universe [physics] [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2019 ftsorbonneuniv https://doi.org/10.1029/2018JC014554 2024-08-01T23:46:51Z International audience The first in situ continuous full-water-column observations of the eastern boundary currents (EBCs) at 34.5°S in the South Atlantic are obtained using 23 months of data from a line of Current and Pressure recording Inverted Echo Sounders (CPIES) spanning the Cape Basin. The CPIES are used to evaluate the mean structure of the EBC, the associated water masses, and the volume transport variability. The estimated northward time-mean Benguela Current absolute geostrophic transport is 24 Sv, with a temporal standard deviation of 17 Sv. Beneath this current the time-mean transport is southward, indicating the presence of a deep-EBC (DEBC), with a time-mean transport of 12 Sv, and a standard deviation of 17 Sv. Offshore of these currents, the shallow and deep flows are more variable with weak time means, likely influenced by Agulhas Rings transiting through the region. Hydrographic data collected along the CPIES line demonstrate that the DEBC is carrying recently ventilated North Atlantic Deep Water, as it flows along the continental slope. This is consistent with a previously hypothesized interior pathway bringing recently ventilated North Atlantic Deep Water from the Deep Western Boundary Current across the Atlantic to the Cape Basin. The observations further indicate that much of the DEBC must recirculate within the basin. Spectral analyses of the shallow and deep EBC transport time series demonstrate that the strongest variability occurs on timescales ranging from 30 to 90 days, associated with the propagation of Agulhas Rings. Article in Journal/Newspaper North Atlantic Deep Water North Atlantic HAL Sorbonne Université Journal of Geophysical Research: Oceans 124 3 1634 1659 |