Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity
Meanders formed where the Antarctic Circumpolar Current (ACC) interacts with topography have been identified as dynamical hot spots, characterized by enhanced eddy energy, momentum transfer, and cross-front exchange. However, few studies have used observations to diagnose the dynamics of ACC standin...
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ftunivtasecite:oai:ecite.utas.edu.au:150436 2023-05-15T13:42:40+02:00 Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity Meijer, JJ Phillips, HE Bindoff, NL Rintoul, SR Foppert, A 2022 https://doi.org/10.1175/JPO-D-21-0049.1 http://ecite.utas.edu.au/150436 en eng Amer Meteorological Soc http://dx.doi.org/10.1175/JPO-D-21-0049.1 Meijer, JJ and Phillips, HE and Bindoff, NL and Rintoul, SR and Foppert, A, Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity, Journal of Physical Oceanography, 52, (6) pp. 1073-1089. ISSN 0022-3670 (2022) [Refereed Article] http://ecite.utas.edu.au/150436 Earth Sciences Oceanography Physical oceanography Refereed Article PeerReviewed 2022 ftunivtasecite https://doi.org/10.1175/JPO-D-21-0049.1 2022-11-07T23:17:17Z Meanders formed where the Antarctic Circumpolar Current (ACC) interacts with topography have been identified as dynamical hot spots, characterized by enhanced eddy energy, momentum transfer, and cross-front exchange. However, few studies have used observations to diagnose the dynamics of ACC standing meanders. We use a synoptic hydrographic survey and satellite altimetry to explore the momentum and vorticity balance of a Subantarctic Front standing meander, downstream of the Southeast Indian Ridge. Along-stream anomalies of temperature in the upper ocean (150-600 m) show along-stream cooling entering the surface trough and along-stream warming entering the surface crest, while warming is observed from trough to crest in the deeper ocean (600-1500 m). Advection of relative vorticity is balanced by vortex stretching, as found in model studies of meandering currents. Meander curvature is sufficiently large that the flow is in gradient wind balance, resulting in ageostrophic horizontal divergence. This drives downwelling of cooler water along isopycnals entering the surface trough and upwelling of warmer water entering the surface crest, consistent with the observed evolution of temperature anomalies in the upper ocean. Progressive along-stream warming observed between 600 and 1500 m likely reflects cyclogenesis in the deep ocean. Vortex stretching couples the upper and lower water column, producing a low pressure at depth between surface trough and crest and cyclonic flow that carries cold water equatorward in the surface trough and warm water poleward in the surface crest (poleward heat flux). The results highlight gradient-wind balance and cyclogenesis as central to dynamics of standing meanders and their critical role in the ACC momentum and vorticity balance. Article in Journal/Newspaper Antarc* Antarctic eCite UTAS (University of Tasmania) Antarctic Indian Southeast Indian Ridge ENVELOPE(110.000,110.000,-50.000,-50.000) The Antarctic Journal of Physical Oceanography 52 6 1073 1089 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Oceanography Physical oceanography |
spellingShingle |
Earth Sciences Oceanography Physical oceanography Meijer, JJ Phillips, HE Bindoff, NL Rintoul, SR Foppert, A Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
topic_facet |
Earth Sciences Oceanography Physical oceanography |
description |
Meanders formed where the Antarctic Circumpolar Current (ACC) interacts with topography have been identified as dynamical hot spots, characterized by enhanced eddy energy, momentum transfer, and cross-front exchange. However, few studies have used observations to diagnose the dynamics of ACC standing meanders. We use a synoptic hydrographic survey and satellite altimetry to explore the momentum and vorticity balance of a Subantarctic Front standing meander, downstream of the Southeast Indian Ridge. Along-stream anomalies of temperature in the upper ocean (150-600 m) show along-stream cooling entering the surface trough and along-stream warming entering the surface crest, while warming is observed from trough to crest in the deeper ocean (600-1500 m). Advection of relative vorticity is balanced by vortex stretching, as found in model studies of meandering currents. Meander curvature is sufficiently large that the flow is in gradient wind balance, resulting in ageostrophic horizontal divergence. This drives downwelling of cooler water along isopycnals entering the surface trough and upwelling of warmer water entering the surface crest, consistent with the observed evolution of temperature anomalies in the upper ocean. Progressive along-stream warming observed between 600 and 1500 m likely reflects cyclogenesis in the deep ocean. Vortex stretching couples the upper and lower water column, producing a low pressure at depth between surface trough and crest and cyclonic flow that carries cold water equatorward in the surface trough and warm water poleward in the surface crest (poleward heat flux). The results highlight gradient-wind balance and cyclogenesis as central to dynamics of standing meanders and their critical role in the ACC momentum and vorticity balance. |
format |
Article in Journal/Newspaper |
author |
Meijer, JJ Phillips, HE Bindoff, NL Rintoul, SR Foppert, A |
author_facet |
Meijer, JJ Phillips, HE Bindoff, NL Rintoul, SR Foppert, A |
author_sort |
Meijer, JJ |
title |
Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
title_short |
Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
title_full |
Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
title_fullStr |
Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
title_full_unstemmed |
Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
title_sort |
dynamics of a standing meander of the subantarctic front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity |
publisher |
Amer Meteorological Soc |
publishDate |
2022 |
url |
https://doi.org/10.1175/JPO-D-21-0049.1 http://ecite.utas.edu.au/150436 |
long_lat |
ENVELOPE(110.000,110.000,-50.000,-50.000) |
geographic |
Antarctic Indian Southeast Indian Ridge The Antarctic |
geographic_facet |
Antarctic Indian Southeast Indian Ridge The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
http://dx.doi.org/10.1175/JPO-D-21-0049.1 Meijer, JJ and Phillips, HE and Bindoff, NL and Rintoul, SR and Foppert, A, Dynamics of a standing meander of the Subantarctic Front diagnosed from satellite altimetry and along-stream anomalies of temperature and salinity, Journal of Physical Oceanography, 52, (6) pp. 1073-1089. ISSN 0022-3670 (2022) [Refereed Article] http://ecite.utas.edu.au/150436 |
op_doi |
https://doi.org/10.1175/JPO-D-21-0049.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
52 |
container_issue |
6 |
container_start_page |
1073 |
op_container_end_page |
1089 |
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1766171498627727360 |