Bottom pressure torque and the vorticity balance from observations in Drake Passage
The vorticity balance of the Antarctic Circumpolar Current in Drake Passage is examined using 4 years of observations from current‐ and pressure‐recording inverted echo sounders. The time‐varying vorticity, planetary and relative vorticity advection, and bottom pressure torque are calculated in a tw...
Published in: | Journal of Geophysical Research: Oceans |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2016
|
Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/525499/ https://nora.nerc.ac.uk/id/eprint/525499/1/Firing_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf https://doi.org/10.1002/2016jc011682 |
id |
ftnerc:oai:nora.nerc.ac.uk:525499 |
---|---|
record_format |
openpolar |
spelling |
ftnerc:oai:nora.nerc.ac.uk:525499 2023-05-15T13:41:44+02:00 Bottom pressure torque and the vorticity balance from observations in Drake Passage Firing, Yvonne L. Chereskin, Teresa K. Watts, D. Randolph Mazloff, Matthew R. 2016 text http://nora.nerc.ac.uk/id/eprint/525499/ https://nora.nerc.ac.uk/id/eprint/525499/1/Firing_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf https://doi.org/10.1002/2016jc011682 en eng https://nora.nerc.ac.uk/id/eprint/525499/1/Firing_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf Firing, Yvonne L. orcid:0000-0002-3640-3974 Chereskin, Teresa K.; Watts, D. Randolph; Mazloff, Matthew R. 2016 Bottom pressure torque and the vorticity balance from observations in Drake Passage. Journal of Geophysical Research: Oceans, 121 (6). 4282-4302. https://doi.org/10.1002/2016jc011682 <https://doi.org/10.1002/2016jc011682> Publication - Article PeerReviewed 2016 ftnerc https://doi.org/10.1002/2016jc011682 2023-02-04T19:49:25Z The vorticity balance of the Antarctic Circumpolar Current in Drake Passage is examined using 4 years of observations from current‐ and pressure‐recording inverted echo sounders. The time‐varying vorticity, planetary and relative vorticity advection, and bottom pressure torque are calculated in a two‐dimensional array in the eddy‐rich Polar Frontal Zone (PFZ). Bottom pressure torque is also estimated at sites across Drake Passage. Mean and eddy nonlinear relative vorticity advection terms dominate over linear advection in the local (50‐km scale) vorticity budget in the PFZ, and are balanced to first order by the divergence of horizontal velocity. Most of this divergence comes from the ageostrophic gradient flow, which also provides a second‐order adjustment to the geostrophic relative vorticity advection. Bottom pressure torque is approximately one‐third the size of the local depth‐integrated divergence. Although the cDrake velocity fields exhibit significant turning with depth throughout Drake Passage even in the mean, surface vorticity advection provides a reasonable representation of the depth‐integrated vorticity balance. Observed near‐bottom currents are strongly topographically steered, and bottom pressure torques grow large where strong near‐bottom flows cross steep topography at small angles. Upslope flow over the northern continental slope dominates the bottom pressure torque in cDrake, and the mean across this Drake Passage transect, 3 to urn:x-wiley:21699275:media:jgrc21771:jgrc21771-math-0001 m s−2, exceeds the mean wind stress curl by a factor of 15–20. Article in Journal/Newspaper Antarc* Antarctic Drake Passage Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Drake Passage Curl ENVELOPE(-63.071,-63.071,-70.797,-70.797) Journal of Geophysical Research: Oceans 121 6 4282 4302 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The vorticity balance of the Antarctic Circumpolar Current in Drake Passage is examined using 4 years of observations from current‐ and pressure‐recording inverted echo sounders. The time‐varying vorticity, planetary and relative vorticity advection, and bottom pressure torque are calculated in a two‐dimensional array in the eddy‐rich Polar Frontal Zone (PFZ). Bottom pressure torque is also estimated at sites across Drake Passage. Mean and eddy nonlinear relative vorticity advection terms dominate over linear advection in the local (50‐km scale) vorticity budget in the PFZ, and are balanced to first order by the divergence of horizontal velocity. Most of this divergence comes from the ageostrophic gradient flow, which also provides a second‐order adjustment to the geostrophic relative vorticity advection. Bottom pressure torque is approximately one‐third the size of the local depth‐integrated divergence. Although the cDrake velocity fields exhibit significant turning with depth throughout Drake Passage even in the mean, surface vorticity advection provides a reasonable representation of the depth‐integrated vorticity balance. Observed near‐bottom currents are strongly topographically steered, and bottom pressure torques grow large where strong near‐bottom flows cross steep topography at small angles. Upslope flow over the northern continental slope dominates the bottom pressure torque in cDrake, and the mean across this Drake Passage transect, 3 to urn:x-wiley:21699275:media:jgrc21771:jgrc21771-math-0001 m s−2, exceeds the mean wind stress curl by a factor of 15–20. |
format |
Article in Journal/Newspaper |
author |
Firing, Yvonne L. Chereskin, Teresa K. Watts, D. Randolph Mazloff, Matthew R. |
spellingShingle |
Firing, Yvonne L. Chereskin, Teresa K. Watts, D. Randolph Mazloff, Matthew R. Bottom pressure torque and the vorticity balance from observations in Drake Passage |
author_facet |
Firing, Yvonne L. Chereskin, Teresa K. Watts, D. Randolph Mazloff, Matthew R. |
author_sort |
Firing, Yvonne L. |
title |
Bottom pressure torque and the vorticity balance from observations in Drake Passage |
title_short |
Bottom pressure torque and the vorticity balance from observations in Drake Passage |
title_full |
Bottom pressure torque and the vorticity balance from observations in Drake Passage |
title_fullStr |
Bottom pressure torque and the vorticity balance from observations in Drake Passage |
title_full_unstemmed |
Bottom pressure torque and the vorticity balance from observations in Drake Passage |
title_sort |
bottom pressure torque and the vorticity balance from observations in drake passage |
publishDate |
2016 |
url |
http://nora.nerc.ac.uk/id/eprint/525499/ https://nora.nerc.ac.uk/id/eprint/525499/1/Firing_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf https://doi.org/10.1002/2016jc011682 |
long_lat |
ENVELOPE(-63.071,-63.071,-70.797,-70.797) |
geographic |
Antarctic The Antarctic Drake Passage Curl |
geographic_facet |
Antarctic The Antarctic Drake Passage Curl |
genre |
Antarc* Antarctic Drake Passage |
genre_facet |
Antarc* Antarctic Drake Passage |
op_relation |
https://nora.nerc.ac.uk/id/eprint/525499/1/Firing_et_al-2016-Journal_of_Geophysical_Research__Oceans.pdf Firing, Yvonne L. orcid:0000-0002-3640-3974 Chereskin, Teresa K.; Watts, D. Randolph; Mazloff, Matthew R. 2016 Bottom pressure torque and the vorticity balance from observations in Drake Passage. Journal of Geophysical Research: Oceans, 121 (6). 4282-4302. https://doi.org/10.1002/2016jc011682 <https://doi.org/10.1002/2016jc011682> |
op_doi |
https://doi.org/10.1002/2016jc011682 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
121 |
container_issue |
6 |
container_start_page |
4282 |
op_container_end_page |
4302 |
_version_ |
1766156066035335168 |