Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean
International audience An enhanced Altimetry Gravest Empirical Mode (AGEM), including both adiabatic and diabatic trends, is developed for the Antarctic Circumpolar Current (ACC) south of Africa using updated hydrographic CTD sections, Argo data, and satellite altimetry. This AGEM has improved accur...
Published in: | Journal of Geophysical Research: Oceans |
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Online Access: | https://insu.hal.science/insu-03727111 https://insu.hal.science/insu-03727111/document https://insu.hal.science/insu-03727111/file/JGR%20Oceans%20-%202016%20-%20Hutchinson%20-%20Decadal%25u2010scale%20thermohaline%20variability%20in%20the%20Atlantic%20sector%20of%20the%20Southern%20Ocean.pdf https://doi.org/10.1002/2015JC011491 |
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ftinsu:oai:HAL:insu-03727111v1 2023-08-27T04:06:13+02:00 Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean Hutchinson, K. Swart, S. Meijers, A. Ansorge, I. Speich, S. Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-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) 2016 https://insu.hal.science/insu-03727111 https://insu.hal.science/insu-03727111/document https://insu.hal.science/insu-03727111/file/JGR%20Oceans%20-%202016%20-%20Hutchinson%20-%20Decadal%25u2010scale%20thermohaline%20variability%20in%20the%20Atlantic%20sector%20of%20the%20Southern%20Ocean.pdf https://doi.org/10.1002/2015JC011491 en eng HAL CCSD Wiley-Blackwell info:eu-repo/semantics/altIdentifier/doi/10.1002/2015JC011491 insu-03727111 https://insu.hal.science/insu-03727111 https://insu.hal.science/insu-03727111/document https://insu.hal.science/insu-03727111/file/JGR%20Oceans%20-%202016%20-%20Hutchinson%20-%20Decadal%25u2010scale%20thermohaline%20variability%20in%20the%20Atlantic%20sector%20of%20the%20Southern%20Ocean.pdf BIBCODE: 2016JGRC.121.3171H doi:10.1002/2015JC011491 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-03727111 Journal of Geophysical Research. Oceans, 2016, 121, pp.3171-3189. ⟨10.1002/2015JC011491⟩ ACC adiabatic diabatic proxy AAIW [SDU]Sciences of the Universe [physics] [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2016 ftinsu https://doi.org/10.1002/2015JC011491 2023-08-02T16:23:00Z International audience An enhanced Altimetry Gravest Empirical Mode (AGEM), including both adiabatic and diabatic trends, is developed for the Antarctic Circumpolar Current (ACC) south of Africa using updated hydrographic CTD sections, Argo data, and satellite altimetry. This AGEM has improved accuracy compared to traditional climatologies and other proxy methods. The AGEM for the Atlantic Southern Ocean offers an ideal technique to investigate the thermohaline variability over the past two decades in a key region for water mass exchanges and transformation. In order to assess and attribute changes in the hydrography of the region, we separate the changes into adiabatic and diabatic components. Integrated over the upper 2000 dbar of the ACC south of Africa, results show mean adiabatic changes of 0.16 ± 0.11°C decade −1 and 0.006 ± 0.014 decade −1 , and diabatic differences of −0.044 ± 0.13°C decade −1 and −0.01 ± 0.017 decade −1 for temperature and salinity, respectively. The trends of the resultant AGEM, that include both adiabatic and diabatic variability (termed AD-AGEM), show a significant increase in the heat content of the upper 2000 dbar of the ACC with a mean warming of 0.12 ± 0.087°C decade −1 . This study focuses on the Antarctic Intermediate Water (AAIW) mass where negative diabatic trends dominate positive adiabatic differences in the Subantarctic Zone (SAZ), with results indicating a cooling (−0.17°C decade −1 ) and freshening (−0.032 decade −1 ) of AAIW in this area, whereas south of the SAZ positive adiabatic and diabatic trends together create a cumulative warming (0.31°C decade −1 ) and salinification (0.014 decade −1 ) of AAIW. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Institut national des sciences de l'Univers: HAL-INSU Antarctic Southern Ocean The Antarctic Journal of Geophysical Research: Oceans 121 5 3171 3189 |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
ACC adiabatic diabatic proxy AAIW [SDU]Sciences of the Universe [physics] [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
ACC adiabatic diabatic proxy AAIW [SDU]Sciences of the Universe [physics] [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Hutchinson, K. Swart, S. Meijers, A. Ansorge, I. Speich, S. Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean |
topic_facet |
ACC adiabatic diabatic proxy AAIW [SDU]Sciences of the Universe [physics] [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience An enhanced Altimetry Gravest Empirical Mode (AGEM), including both adiabatic and diabatic trends, is developed for the Antarctic Circumpolar Current (ACC) south of Africa using updated hydrographic CTD sections, Argo data, and satellite altimetry. This AGEM has improved accuracy compared to traditional climatologies and other proxy methods. The AGEM for the Atlantic Southern Ocean offers an ideal technique to investigate the thermohaline variability over the past two decades in a key region for water mass exchanges and transformation. In order to assess and attribute changes in the hydrography of the region, we separate the changes into adiabatic and diabatic components. Integrated over the upper 2000 dbar of the ACC south of Africa, results show mean adiabatic changes of 0.16 ± 0.11°C decade −1 and 0.006 ± 0.014 decade −1 , and diabatic differences of −0.044 ± 0.13°C decade −1 and −0.01 ± 0.017 decade −1 for temperature and salinity, respectively. The trends of the resultant AGEM, that include both adiabatic and diabatic variability (termed AD-AGEM), show a significant increase in the heat content of the upper 2000 dbar of the ACC with a mean warming of 0.12 ± 0.087°C decade −1 . This study focuses on the Antarctic Intermediate Water (AAIW) mass where negative diabatic trends dominate positive adiabatic differences in the Subantarctic Zone (SAZ), with results indicating a cooling (−0.17°C decade −1 ) and freshening (−0.032 decade −1 ) of AAIW in this area, whereas south of the SAZ positive adiabatic and diabatic trends together create a cumulative warming (0.31°C decade −1 ) and salinification (0.014 decade −1 ) of AAIW. |
author2 |
Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-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) |
format |
Article in Journal/Newspaper |
author |
Hutchinson, K. Swart, S. Meijers, A. Ansorge, I. Speich, S. |
author_facet |
Hutchinson, K. Swart, S. Meijers, A. Ansorge, I. Speich, S. |
author_sort |
Hutchinson, K. |
title |
Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean |
title_short |
Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean |
title_full |
Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean |
title_fullStr |
Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean |
title_full_unstemmed |
Decadal-scale thermohaline variability in the Atlantic sector of the Southern Ocean |
title_sort |
decadal-scale thermohaline variability in the atlantic sector of the southern ocean |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://insu.hal.science/insu-03727111 https://insu.hal.science/insu-03727111/document https://insu.hal.science/insu-03727111/file/JGR%20Oceans%20-%202016%20-%20Hutchinson%20-%20Decadal%25u2010scale%20thermohaline%20variability%20in%20the%20Atlantic%20sector%20of%20the%20Southern%20Ocean.pdf https://doi.org/10.1002/2015JC011491 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://insu.hal.science/insu-03727111 Journal of Geophysical Research. Oceans, 2016, 121, pp.3171-3189. ⟨10.1002/2015JC011491⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1002/2015JC011491 insu-03727111 https://insu.hal.science/insu-03727111 https://insu.hal.science/insu-03727111/document https://insu.hal.science/insu-03727111/file/JGR%20Oceans%20-%202016%20-%20Hutchinson%20-%20Decadal%25u2010scale%20thermohaline%20variability%20in%20the%20Atlantic%20sector%20of%20the%20Southern%20Ocean.pdf BIBCODE: 2016JGRC.121.3171H doi:10.1002/2015JC011491 |
op_rights |
http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1002/2015JC011491 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
121 |
container_issue |
5 |
container_start_page |
3171 |
op_container_end_page |
3189 |
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1775347004938911744 |