Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results
Enhanced vertical velocities associated with submesoscale motions may rapidly modify mixed layer depths and increase exchange between the mixed layer and the ocean interior. These dynamics are of particular importance in the Southern Ocean, where the ventilation of many density classes occurs. Here...
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ftcaltechauth:oai:authors.library.caltech.edu:89759 2023-05-15T16:02:30+02:00 Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results Viglione, Giuliana A. Thompson, Andrew F. Flexas, M. Mar Sprintall, Janet Swart, Sebastiaan 2018-09 application/pdf https://authors.library.caltech.edu/89759/ https://authors.library.caltech.edu/89759/1/jpo-d-17-0192.1.pdf https://resolver.caltech.edu/CaltechAUTHORS:20180919-144812027 en eng American Meteorological Society https://authors.library.caltech.edu/89759/1/jpo-d-17-0192.1.pdf Viglione, Giuliana A. and Thompson, Andrew F. and Flexas, M. Mar and Sprintall, Janet and Swart, Sebastiaan (2018) Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results. Journal of Physical Oceanography, 48 (9). pp. 2011-2027. ISSN 0022-3670. doi:10.1175/JPO-D-17-0192.1. https://resolver.caltech.edu/CaltechAUTHORS:20180919-144812027 <https://resolver.caltech.edu/CaltechAUTHORS:20180919-144812027> other Article PeerReviewed 2018 ftcaltechauth https://doi.org/10.1175/JPO-D-17-0192.1 2021-11-18T18:47:48Z Enhanced vertical velocities associated with submesoscale motions may rapidly modify mixed layer depths and increase exchange between the mixed layer and the ocean interior. These dynamics are of particular importance in the Southern Ocean, where the ventilation of many density classes occurs. Here we present results from an observational field program in southern Drake Passage, a region preconditioned for submesoscale instability owing to its strong mesoscale eddy field, persistent fronts, strong down-front winds, and weak vertical stratification. Two gliders sampled from December 2014 through March 2015 upstream and downstream of the Shackleton Fracture Zone (SFZ). The acquired time series of mixed layer depths and buoyancy gradients enabled calculations of potential vorticity and classifications of submesoscale instabilities. The regions flanking the SFZ displayed remarkably different characteristics despite similar surface forcing. Mixed layer depths were nearly twice as deep, and horizontal buoyancy gradients were larger downstream of the SFZ. Upstream of the SFZ, submesoscale variability was confined to the edges of topographically steered fronts, whereas downstream these motions were more broadly distributed. Comparisons to a one-dimensional (1D) mixing model demonstrate the role of submesoscale instabilities in generating mixed layer variance. Numerical output from a submesoscale-resolving simulation indicates that submesoscale instabilities are crucial for correctly reproducing upper-ocean stratification. These results show that bathymetry can play a key role in generating dynamically distinct submesoscale characteristics over short spatial scales and that submesoscale motions can be locally active during summer months. Article in Journal/Newspaper Drake Passage Southern Ocean Caltech Authors (California Institute of Technology) Drake Passage Shackleton Shackleton Fracture Zone ENVELOPE(-60.000,-60.000,-60.000,-60.000) Southern Ocean Journal of Physical Oceanography 48 9 2011 2027 |
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Open Polar |
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Caltech Authors (California Institute of Technology) |
op_collection_id |
ftcaltechauth |
language |
English |
description |
Enhanced vertical velocities associated with submesoscale motions may rapidly modify mixed layer depths and increase exchange between the mixed layer and the ocean interior. These dynamics are of particular importance in the Southern Ocean, where the ventilation of many density classes occurs. Here we present results from an observational field program in southern Drake Passage, a region preconditioned for submesoscale instability owing to its strong mesoscale eddy field, persistent fronts, strong down-front winds, and weak vertical stratification. Two gliders sampled from December 2014 through March 2015 upstream and downstream of the Shackleton Fracture Zone (SFZ). The acquired time series of mixed layer depths and buoyancy gradients enabled calculations of potential vorticity and classifications of submesoscale instabilities. The regions flanking the SFZ displayed remarkably different characteristics despite similar surface forcing. Mixed layer depths were nearly twice as deep, and horizontal buoyancy gradients were larger downstream of the SFZ. Upstream of the SFZ, submesoscale variability was confined to the edges of topographically steered fronts, whereas downstream these motions were more broadly distributed. Comparisons to a one-dimensional (1D) mixing model demonstrate the role of submesoscale instabilities in generating mixed layer variance. Numerical output from a submesoscale-resolving simulation indicates that submesoscale instabilities are crucial for correctly reproducing upper-ocean stratification. These results show that bathymetry can play a key role in generating dynamically distinct submesoscale characteristics over short spatial scales and that submesoscale motions can be locally active during summer months. |
format |
Article in Journal/Newspaper |
author |
Viglione, Giuliana A. Thompson, Andrew F. Flexas, M. Mar Sprintall, Janet Swart, Sebastiaan |
spellingShingle |
Viglione, Giuliana A. Thompson, Andrew F. Flexas, M. Mar Sprintall, Janet Swart, Sebastiaan Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results |
author_facet |
Viglione, Giuliana A. Thompson, Andrew F. Flexas, M. Mar Sprintall, Janet Swart, Sebastiaan |
author_sort |
Viglione, Giuliana A. |
title |
Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results |
title_short |
Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results |
title_full |
Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results |
title_fullStr |
Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results |
title_full_unstemmed |
Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results |
title_sort |
abrupt transitions in submesoscale structure in southern drake passage: glider observations and model results |
publisher |
American Meteorological Society |
publishDate |
2018 |
url |
https://authors.library.caltech.edu/89759/ https://authors.library.caltech.edu/89759/1/jpo-d-17-0192.1.pdf https://resolver.caltech.edu/CaltechAUTHORS:20180919-144812027 |
long_lat |
ENVELOPE(-60.000,-60.000,-60.000,-60.000) |
geographic |
Drake Passage Shackleton Shackleton Fracture Zone Southern Ocean |
geographic_facet |
Drake Passage Shackleton Shackleton Fracture Zone Southern Ocean |
genre |
Drake Passage Southern Ocean |
genre_facet |
Drake Passage Southern Ocean |
op_relation |
https://authors.library.caltech.edu/89759/1/jpo-d-17-0192.1.pdf Viglione, Giuliana A. and Thompson, Andrew F. and Flexas, M. Mar and Sprintall, Janet and Swart, Sebastiaan (2018) Abrupt Transitions in Submesoscale Structure in Southern Drake Passage: Glider Observations and Model Results. Journal of Physical Oceanography, 48 (9). pp. 2011-2027. ISSN 0022-3670. doi:10.1175/JPO-D-17-0192.1. https://resolver.caltech.edu/CaltechAUTHORS:20180919-144812027 <https://resolver.caltech.edu/CaltechAUTHORS:20180919-144812027> |
op_rights |
other |
op_doi |
https://doi.org/10.1175/JPO-D-17-0192.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
48 |
container_issue |
9 |
container_start_page |
2011 |
op_container_end_page |
2027 |
_version_ |
1766398154021797888 |