The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data
The momentum balance of the Antarctic Circumpolar Current is investigated using both output from a highresolution primitive equation model and sea surface height measurements from the Geosat altimeter. In the Semtner–Chervin general circulation model, run with approximately one-quarter degree resolu...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.412.555 2023-05-15T13:45:56+02:00 The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data Sarah T. Gille The Pennsylvania State University CiteSeerX Archives 1997 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.412.555 http://www-pord.ucsd.edu/~sgille/pub_dir/jpo_gille_1997_momentum.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.412.555 http://www-pord.ucsd.edu/~sgille/pub_dir/jpo_gille_1997_momentum.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www-pord.ucsd.edu/~sgille/pub_dir/jpo_gille_1997_momentum.pdf text 1997 ftciteseerx 2016-01-08T03:25:13Z The momentum balance of the Antarctic Circumpolar Current is investigated using both output from a highresolution primitive equation model and sea surface height measurements from the Geosat altimeter. In the Semtner–Chervin general circulation model, run with approximately one-quarter degree resolution and timevarying ECMWF winds, topographic form stress is the dominant process balancing the surface wind forcing. Detailed examination of form stress in the model indicates that it is due to three large topographic obstructions located at Kerguelen Island, Campbell Plateau, and Drake Passage. The difference between wind stress and form stress represents the lateral transfer of momentum into and out of the ACC. It is examined both in zonal coordinates to conform to the model architecture and along mean streamlines in order to reduce the effects of standing eddies. In this particular model, in stream coordinates, biharmonic friction dominates the lateral transfer of momentum. Since biharmonic friction is a parameterization of subgrid-scale transient eddy processes, this indicates that the unresolved transient eddy processes play a critical role in fluxing momentum across the ACC in this model. Although the relative importance of individual terms in the momentum balance does not vary substantially along streamlines, elevated levels of eddy kinetic energy are associated with the three major topographic features. In contrast, altimeter data show elevated energy levels at many more topographic features of intermediate scales, suggesting that smaller topographic effects are better able to communicate with the surface in the real ocean than in the model. 1. Text Antarc* Antarctic Drake Passage Southern Ocean Unknown Antarctic Campbell Plateau ENVELOPE(171.000,171.000,-50.667,-50.667) Drake Passage Kerguelen Kerguelen Island ENVELOPE(69.500,69.500,-49.250,-49.250) Southern Ocean The Antarctic |
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English |
description |
The momentum balance of the Antarctic Circumpolar Current is investigated using both output from a highresolution primitive equation model and sea surface height measurements from the Geosat altimeter. In the Semtner–Chervin general circulation model, run with approximately one-quarter degree resolution and timevarying ECMWF winds, topographic form stress is the dominant process balancing the surface wind forcing. Detailed examination of form stress in the model indicates that it is due to three large topographic obstructions located at Kerguelen Island, Campbell Plateau, and Drake Passage. The difference between wind stress and form stress represents the lateral transfer of momentum into and out of the ACC. It is examined both in zonal coordinates to conform to the model architecture and along mean streamlines in order to reduce the effects of standing eddies. In this particular model, in stream coordinates, biharmonic friction dominates the lateral transfer of momentum. Since biharmonic friction is a parameterization of subgrid-scale transient eddy processes, this indicates that the unresolved transient eddy processes play a critical role in fluxing momentum across the ACC in this model. Although the relative importance of individual terms in the momentum balance does not vary substantially along streamlines, elevated levels of eddy kinetic energy are associated with the three major topographic features. In contrast, altimeter data show elevated energy levels at many more topographic features of intermediate scales, suggesting that smaller topographic effects are better able to communicate with the surface in the real ocean than in the model. 1. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Sarah T. Gille |
spellingShingle |
Sarah T. Gille The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data |
author_facet |
Sarah T. Gille |
author_sort |
Sarah T. Gille |
title |
The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data |
title_short |
The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data |
title_full |
The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data |
title_fullStr |
The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data |
title_full_unstemmed |
The Southern Ocean momentum balance: Evidence for topographic effects from numerical model output and altimeter data |
title_sort |
southern ocean momentum balance: evidence for topographic effects from numerical model output and altimeter data |
publishDate |
1997 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.412.555 http://www-pord.ucsd.edu/~sgille/pub_dir/jpo_gille_1997_momentum.pdf |
long_lat |
ENVELOPE(171.000,171.000,-50.667,-50.667) ENVELOPE(69.500,69.500,-49.250,-49.250) |
geographic |
Antarctic Campbell Plateau Drake Passage Kerguelen Kerguelen Island Southern Ocean The Antarctic |
geographic_facet |
Antarctic Campbell Plateau Drake Passage Kerguelen Kerguelen Island Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Drake Passage Southern Ocean |
genre_facet |
Antarc* Antarctic Drake Passage Southern Ocean |
op_source |
http://www-pord.ucsd.edu/~sgille/pub_dir/jpo_gille_1997_momentum.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.412.555 http://www-pord.ucsd.edu/~sgille/pub_dir/jpo_gille_1997_momentum.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766232803148562432 |