An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts
International audience Swart et al. (2010) applied altimetry data to the gravest empirical mode south of Africa to yield a 16 year time series of temperature and salinity sections. In this study we use these thermohaline sections to derive weekly estimates of heat content (HC) and salt content (SC)...
Published in: | Journal of Geophysical Research |
---|---|
Main Authors: | , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2010
|
Subjects: | |
Online Access: | https://hal.science/hal-00495103 https://doi.org/10.1029/2009JC005300 |
id |
ftunivbrest:oai:HAL:hal-00495103v1 |
---|---|
record_format |
openpolar |
spelling |
ftunivbrest:oai:HAL:hal-00495103v1 2023-12-17T10:18:48+01:00 An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts Swart, Sebastiaan Speich, Sabrina Department of Oceanography Cape Town University of Cape Town Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2010 https://hal.science/hal-00495103 https://doi.org/10.1029/2009JC005300 en eng HAL CCSD Wiley-Blackwell info:eu-repo/semantics/altIdentifier/doi/10.1029/2009JC005300 hal-00495103 https://hal.science/hal-00495103 doi:10.1029/2009JC005300 ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.science/hal-00495103 Journal of Geophysical Research. Oceans, 2010, 115, pp.C03003. ⟨10.1029/2009JC005300⟩ [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2010 ftunivbrest https://doi.org/10.1029/2009JC005300 2023-11-21T23:37:03Z International audience Swart et al. (2010) applied altimetry data to the gravest empirical mode south of Africa to yield a 16 year time series of temperature and salinity sections. In this study we use these thermohaline sections to derive weekly estimates of heat content (HC) and salt content (SC) at the GoodHope meridional transect of the Antarctic Circumpolar Current (ACC). These estimates compare favorably to observed data. The resulting 16 year time series of HC and SC estimates are used to explain the subsurface thermohaline variability at each ACC front and frontal zone. The variability at the Subantarctic Zone (SAZ) is principally driven by the presence of Agulhas Rings, which occur in this region approximately 2.7 times per annum and are responsible for the longest and highest scales of observed variability. The variability of the SAZ is responsible for over 50% and 60% of the total ACC HC and SC variability, respectively. Poleward of the SAZ, the variability is largely determined by the influence of the local topography on the fronts of the region and can be explained by the conservation of potential vorticity. Wavelet analysis is conducted on the time series of meridionally integrated HC and SC in each ACC front and frontal zone, revealing a consistent seasonal mode that becomes more dominant toward the southern limit of the ACC. The lower‐frequency signals are compared with two dominant modes of variability in the Southern Ocean. The Southern Annular Mode correlates well with the HC and SC anomaly estimates at the Antarctic Polar Front, while the Southern Oscillation Index appears to have connections to the variability found in the very southern domains of the ACC. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Université de Bretagne Occidentale: HAL Antarctic Southern Ocean The Antarctic Journal of Geophysical Research 115 C3 |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
language |
English |
topic |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Swart, Sebastiaan Speich, Sabrina An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts |
topic_facet |
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience Swart et al. (2010) applied altimetry data to the gravest empirical mode south of Africa to yield a 16 year time series of temperature and salinity sections. In this study we use these thermohaline sections to derive weekly estimates of heat content (HC) and salt content (SC) at the GoodHope meridional transect of the Antarctic Circumpolar Current (ACC). These estimates compare favorably to observed data. The resulting 16 year time series of HC and SC estimates are used to explain the subsurface thermohaline variability at each ACC front and frontal zone. The variability at the Subantarctic Zone (SAZ) is principally driven by the presence of Agulhas Rings, which occur in this region approximately 2.7 times per annum and are responsible for the longest and highest scales of observed variability. The variability of the SAZ is responsible for over 50% and 60% of the total ACC HC and SC variability, respectively. Poleward of the SAZ, the variability is largely determined by the influence of the local topography on the fronts of the region and can be explained by the conservation of potential vorticity. Wavelet analysis is conducted on the time series of meridionally integrated HC and SC in each ACC front and frontal zone, revealing a consistent seasonal mode that becomes more dominant toward the southern limit of the ACC. The lower‐frequency signals are compared with two dominant modes of variability in the Southern Ocean. The Southern Annular Mode correlates well with the HC and SC anomaly estimates at the Antarctic Polar Front, while the Southern Oscillation Index appears to have connections to the variability found in the very southern domains of the ACC. |
author2 |
Department of Oceanography Cape Town University of Cape Town Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Swart, Sebastiaan Speich, Sabrina |
author_facet |
Swart, Sebastiaan Speich, Sabrina |
author_sort |
Swart, Sebastiaan |
title |
An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts |
title_short |
An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts |
title_full |
An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts |
title_fullStr |
An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts |
title_full_unstemmed |
An altimetry‐based gravest empirical mode south of Africa: 2. Dynamic nature of the Antarctic Circumpolar Current fronts |
title_sort |
altimetry‐based gravest empirical mode south of africa: 2. dynamic nature of the antarctic circumpolar current fronts |
publisher |
HAL CCSD |
publishDate |
2010 |
url |
https://hal.science/hal-00495103 https://doi.org/10.1029/2009JC005300 |
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://hal.science/hal-00495103 Journal of Geophysical Research. Oceans, 2010, 115, pp.C03003. ⟨10.1029/2009JC005300⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2009JC005300 hal-00495103 https://hal.science/hal-00495103 doi:10.1029/2009JC005300 |
op_doi |
https://doi.org/10.1029/2009JC005300 |
container_title |
Journal of Geophysical Research |
container_volume |
115 |
container_issue |
C3 |
_version_ |
1785579395260350464 |