Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations
Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 327–348, doi:10.1175/JPO-D-15-0112.1. Po...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/7795 2023-05-15T17:32:02+02:00 Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations Todd, Robert E. Owens, W. Brechner Rudnick, Daniel L. 2016-01 https://hdl.handle.net/1912/7795 en_US eng American Meteorological Society https://doi.org/10.1175/JPO-D-15-0112.1 Journal of Physical Oceanography 46 (2016): 327–348 https://hdl.handle.net/1912/7795 doi:10.1175/JPO-D-15-0112.1 Journal of Physical Oceanography 46 (2016): 327–348 doi:10.1175/JPO-D-15-0112.1 Geographic location/entity North Atlantic Ocean Circulation/ Dynamics Boundary currents Potential vorticity Atm/Ocean Structure/ Phenomena Article 2016 ftwhoas https://doi.org/10.1175/JPO-D-15-0112.1 2022-05-28T22:59:30Z Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 327–348, doi:10.1175/JPO-D-15-0112.1. Potential vorticity structure in two segments of the North Atlantic’s western boundary current is examined using concurrent, high-resolution measurements of hydrography and velocity from gliders. Spray gliders occupied 40 transects across the Loop Current in the Gulf of Mexico and 11 transects across the Gulf Stream downstream of Cape Hatteras. Cross-stream distributions of the Ertel potential vorticity and its components are calculated for each transect under the assumptions that all flow is in the direction of measured vertically averaged currents and that the flow is geostrophic. Mean cross-stream distributions of hydrographic properties, potential vorticity, and alongstream velocity are calculated for both the Loop Current and the detached Gulf Stream in both depth and density coordinates. Differences between these mean transects highlight the downstream changes in western boundary current structure. As the current increases its transport downstream, upper-layer potential vorticity is generally reduced because of the combined effects of increased anticyclonic relative vorticity, reduced stratification, and increased cross-stream density gradients. The only exception is within the 20-km-wide cyclonic flank of the Gulf Stream, where intense cyclonic relative vorticity results in more positive potential vorticity than in the Loop Current. Cross-stream gradients of mean potential vorticity satisfy necessary conditions for both barotropic and baroclinic instability within the western boundary current. Instances of very low or negative potential vorticity, which predispose the flow to various overturning instabilities, are observed in individual transects across both the Loop Current and the Gulf Stream. Glider ... Article in Journal/Newspaper North Atlantic Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Journal of Physical Oceanography 46 1 327 348 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Geographic location/entity North Atlantic Ocean Circulation/ Dynamics Boundary currents Potential vorticity Atm/Ocean Structure/ Phenomena |
spellingShingle |
Geographic location/entity North Atlantic Ocean Circulation/ Dynamics Boundary currents Potential vorticity Atm/Ocean Structure/ Phenomena Todd, Robert E. Owens, W. Brechner Rudnick, Daniel L. Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations |
topic_facet |
Geographic location/entity North Atlantic Ocean Circulation/ Dynamics Boundary currents Potential vorticity Atm/Ocean Structure/ Phenomena |
description |
Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 327–348, doi:10.1175/JPO-D-15-0112.1. Potential vorticity structure in two segments of the North Atlantic’s western boundary current is examined using concurrent, high-resolution measurements of hydrography and velocity from gliders. Spray gliders occupied 40 transects across the Loop Current in the Gulf of Mexico and 11 transects across the Gulf Stream downstream of Cape Hatteras. Cross-stream distributions of the Ertel potential vorticity and its components are calculated for each transect under the assumptions that all flow is in the direction of measured vertically averaged currents and that the flow is geostrophic. Mean cross-stream distributions of hydrographic properties, potential vorticity, and alongstream velocity are calculated for both the Loop Current and the detached Gulf Stream in both depth and density coordinates. Differences between these mean transects highlight the downstream changes in western boundary current structure. As the current increases its transport downstream, upper-layer potential vorticity is generally reduced because of the combined effects of increased anticyclonic relative vorticity, reduced stratification, and increased cross-stream density gradients. The only exception is within the 20-km-wide cyclonic flank of the Gulf Stream, where intense cyclonic relative vorticity results in more positive potential vorticity than in the Loop Current. Cross-stream gradients of mean potential vorticity satisfy necessary conditions for both barotropic and baroclinic instability within the western boundary current. Instances of very low or negative potential vorticity, which predispose the flow to various overturning instabilities, are observed in individual transects across both the Loop Current and the Gulf Stream. Glider ... |
format |
Article in Journal/Newspaper |
author |
Todd, Robert E. Owens, W. Brechner Rudnick, Daniel L. |
author_facet |
Todd, Robert E. Owens, W. Brechner Rudnick, Daniel L. |
author_sort |
Todd, Robert E. |
title |
Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations |
title_short |
Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations |
title_full |
Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations |
title_fullStr |
Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations |
title_full_unstemmed |
Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations |
title_sort |
potential vorticity structure in the north atlantic western boundary current from underwater glider observations |
publisher |
American Meteorological Society |
publishDate |
2016 |
url |
https://hdl.handle.net/1912/7795 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Journal of Physical Oceanography 46 (2016): 327–348 doi:10.1175/JPO-D-15-0112.1 |
op_relation |
https://doi.org/10.1175/JPO-D-15-0112.1 Journal of Physical Oceanography 46 (2016): 327–348 https://hdl.handle.net/1912/7795 doi:10.1175/JPO-D-15-0112.1 |
op_doi |
https://doi.org/10.1175/JPO-D-15-0112.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
46 |
container_issue |
1 |
container_start_page |
327 |
op_container_end_page |
348 |
_version_ |
1766129950339891200 |