q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability
A study of mesoscale subduction at the Antarctic Polar Front (PF) is conducted by use of hydrographic data from a high-resolution, quasi-synoptic survey of the front. The geostrophic velocity and isopycnal potential vorticity (PV) fields are computed, and the ageostrophic flow diagnosed from the sem...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.527.3789 2023-05-15T13:42:41+02:00 q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability Alberto C. Naveira Garabato John T. Allen Harry Leach Volker H. Strass Raymond T. Pollard The Pennsylvania State University CiteSeerX Archives 2000 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.527.3789 http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal01.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.527.3789 http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal01.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal01.pdf text 2000 ftciteseerx 2016-01-08T10:24:56Z A study of mesoscale subduction at the Antarctic Polar Front (PF) is conducted by use of hydrographic data from a high-resolution, quasi-synoptic survey of the front. The geostrophic velocity and isopycnal potential vorticity (PV) fields are computed, and the ageostrophic flow diagnosed from the semigeostrophic omega equation. It is found that the ageostrophic circulation induced by baroclinic instability counteracts the frontogenesis and frontolysis effected by the confluence and difluence, respectively, of the geostrophic velocity field. Though the sense of the ageostrophic circulation is reversed repeatedly along the front, the existence of PV gradients along isopycnals leads to a net cross-front ‘‘bolus’ ’ transport. In response to a reversal of this gradient with depth (a necessary condition for the onset of baroclinic instability), the bolus transport is northward at the protruding temperature minimum layer that characterizes the PF, and southward above. This net cross-front overturning circulation acts to flatten the isopycnals of the front and results in a subduction of the temperature minimum layer as it progresses northward along isopycnals. Consistently, a net baroclinic conversion rate of approximately 1 cm2 s22 d21, corresponding to a net subduction rate of O(20 m yr21), is calculated in the survey area. The similarity between the PV field of the PF and other Southern Ocean fronts suggests that the authors ’ results may also be applicable there. This has profound implications for the understanding of the zonation of the Antarctic Circumpolar Current. 1. Text Antarc* Antarctic Southern Ocean Unknown Antarctic Southern Ocean The Antarctic |
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Open Polar |
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Unknown |
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ftciteseerx |
language |
English |
description |
A study of mesoscale subduction at the Antarctic Polar Front (PF) is conducted by use of hydrographic data from a high-resolution, quasi-synoptic survey of the front. The geostrophic velocity and isopycnal potential vorticity (PV) fields are computed, and the ageostrophic flow diagnosed from the semigeostrophic omega equation. It is found that the ageostrophic circulation induced by baroclinic instability counteracts the frontogenesis and frontolysis effected by the confluence and difluence, respectively, of the geostrophic velocity field. Though the sense of the ageostrophic circulation is reversed repeatedly along the front, the existence of PV gradients along isopycnals leads to a net cross-front ‘‘bolus’ ’ transport. In response to a reversal of this gradient with depth (a necessary condition for the onset of baroclinic instability), the bolus transport is northward at the protruding temperature minimum layer that characterizes the PF, and southward above. This net cross-front overturning circulation acts to flatten the isopycnals of the front and results in a subduction of the temperature minimum layer as it progresses northward along isopycnals. Consistently, a net baroclinic conversion rate of approximately 1 cm2 s22 d21, corresponding to a net subduction rate of O(20 m yr21), is calculated in the survey area. The similarity between the PV field of the PF and other Southern Ocean fronts suggests that the authors ’ results may also be applicable there. This has profound implications for the understanding of the zonation of the Antarctic Circumpolar Current. 1. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Alberto C. Naveira Garabato John T. Allen Harry Leach Volker H. Strass Raymond T. Pollard |
spellingShingle |
Alberto C. Naveira Garabato John T. Allen Harry Leach Volker H. Strass Raymond T. Pollard q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability |
author_facet |
Alberto C. Naveira Garabato John T. Allen Harry Leach Volker H. Strass Raymond T. Pollard |
author_sort |
Alberto C. Naveira Garabato |
title |
q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability |
title_short |
q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability |
title_full |
q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability |
title_fullStr |
q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability |
title_full_unstemmed |
q 2001 American Meteorological Society Mesoscale Subduction at the Antarctic Polar Front Driven by Baroclinic Instability |
title_sort |
q 2001 american meteorological society mesoscale subduction at the antarctic polar front driven by baroclinic instability |
publishDate |
2000 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.527.3789 http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal01.pdf |
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 |
http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal01.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.527.3789 http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal01.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766171849328164864 |