Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales
It is well-established that, at periods shorter than a year, variations in Antarctic circumpolar transport are reflected in a barotropic mode, known as the southern mode, in which sea level and bottom pressure varies coherently around Antarctica. Here, we use two multidecadal ocean model runs to inv...
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2014
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00020264 2023-05-15T13:41:02+02:00 Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales Hughes, C. W. Williams, Joanne Coward, A. C. de Cuevas, B. A. 2014-04 electronic https://doi.org/10.5194/os-10-215-2014 https://noa.gwlb.de/receive/cop_mods_00020264 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020219/os-10-215-2014.pdf https://os.copernicus.org/articles/10/215/2014/os-10-215-2014.pdf eng eng Copernicus Publications Ocean Science -- http://www.bibliothek.uni-regensburg.de/ezeit/?2183769 -- http://www.copernicus.org/EGU/os/os.html -- 1812-0792 https://doi.org/10.5194/os-10-215-2014 https://noa.gwlb.de/receive/cop_mods_00020264 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020219/os-10-215-2014.pdf https://os.copernicus.org/articles/10/215/2014/os-10-215-2014.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2014 ftnonlinearchiv https://doi.org/10.5194/os-10-215-2014 2022-02-08T22:52:15Z It is well-established that, at periods shorter than a year, variations in Antarctic circumpolar transport are reflected in a barotropic mode, known as the southern mode, in which sea level and bottom pressure varies coherently around Antarctica. Here, we use two multidecadal ocean model runs to investigate the behaviour of the southern mode at timescales on which density changes become important, leading to a baroclinic component to the adjustment. We find that the concept of a southern mode in bottom pressure remains valid, and remains a direct measure of the circumpolar transport, with changes at the northern boundary playing only a small role even on decadal timescales. However, at periods longer than about 5 years, density changes start to play a role, leading to a surface intensification of the vertical profile of the transport. We also find that barotropic currents on the continental slope account for a significant fraction of the variability, and produce surface intensification in the meridional-integral flow. Circumpolar sea level and transport are related at all investigated timescales. However, the role of density variations results in a ratio of sea level change to transport which becomes larger at longer timescales. This means that any long-term transport monitoring strategy based on present measurement systems must involve multiplying the observed quantity by a factor which depends on frequency. Article in Journal/Newspaper Antarc* Antarctic Antarctica Niedersächsisches Online-Archiv NOA Antarctic Ocean Science 10 2 215 225 |
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Niedersächsisches Online-Archiv NOA |
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language |
English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Hughes, C. W. Williams, Joanne Coward, A. C. de Cuevas, B. A. Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
topic_facet |
article Verlagsveröffentlichung |
description |
It is well-established that, at periods shorter than a year, variations in Antarctic circumpolar transport are reflected in a barotropic mode, known as the southern mode, in which sea level and bottom pressure varies coherently around Antarctica. Here, we use two multidecadal ocean model runs to investigate the behaviour of the southern mode at timescales on which density changes become important, leading to a baroclinic component to the adjustment. We find that the concept of a southern mode in bottom pressure remains valid, and remains a direct measure of the circumpolar transport, with changes at the northern boundary playing only a small role even on decadal timescales. However, at periods longer than about 5 years, density changes start to play a role, leading to a surface intensification of the vertical profile of the transport. We also find that barotropic currents on the continental slope account for a significant fraction of the variability, and produce surface intensification in the meridional-integral flow. Circumpolar sea level and transport are related at all investigated timescales. However, the role of density variations results in a ratio of sea level change to transport which becomes larger at longer timescales. This means that any long-term transport monitoring strategy based on present measurement systems must involve multiplying the observed quantity by a factor which depends on frequency. |
format |
Article in Journal/Newspaper |
author |
Hughes, C. W. Williams, Joanne Coward, A. C. de Cuevas, B. A. |
author_facet |
Hughes, C. W. Williams, Joanne Coward, A. C. de Cuevas, B. A. |
author_sort |
Hughes, C. W. |
title |
Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
title_short |
Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
title_full |
Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
title_fullStr |
Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
title_full_unstemmed |
Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
title_sort |
antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/os-10-215-2014 https://noa.gwlb.de/receive/cop_mods_00020264 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020219/os-10-215-2014.pdf https://os.copernicus.org/articles/10/215/2014/os-10-215-2014.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_relation |
Ocean Science -- http://www.bibliothek.uni-regensburg.de/ezeit/?2183769 -- http://www.copernicus.org/EGU/os/os.html -- 1812-0792 https://doi.org/10.5194/os-10-215-2014 https://noa.gwlb.de/receive/cop_mods_00020264 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00020219/os-10-215-2014.pdf https://os.copernicus.org/articles/10/215/2014/os-10-215-2014.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/os-10-215-2014 |
container_title |
Ocean Science |
container_volume |
10 |
container_issue |
2 |
container_start_page |
215 |
op_container_end_page |
225 |
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1766144814625062912 |