Subduction on the northern and southern flanks of the Gulf Stream
Author Posting. © American Meteorological Society, 2010. 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 40 (2010): 429-438, doi:10.1175/2009JPO4187.1. Sect...
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Online Access: | https://hdl.handle.net/1912/3957 |
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/3957 2023-05-15T17:36:11+02:00 Subduction on the northern and southern flanks of the Gulf Stream Thomas, Leif N. Joyce, Terrence M. 2010-02 application/pdf https://hdl.handle.net/1912/3957 en_US eng American Meteorological Society https://doi.org/10.1175/2009JPO4187.1 Journal of Physical Oceanography 40 (2010): 429-438 https://hdl.handle.net/1912/3957 doi:10.1175/2009JPO4187.1 Journal of Physical Oceanography 40 (2010): 429-438 doi:10.1175/2009JPO4187.1 Ocean circulation Thermohaline circulation Frontogenesis/frontolysis Article 2010 ftwhoas https://doi.org/10.1175/2009JPO4187.1 2022-05-28T22:58:09Z Author Posting. © American Meteorological Society, 2010. 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 40 (2010): 429-438, doi:10.1175/2009JPO4187.1. Sections of temperature, salinity, dissolved oxygen, and velocity were made crossing the Gulf Stream in late January 2006 to investigate the role of frontal processes in the formation of Eighteen Degree Water (EDW), the Subtropical Mode Water of the North Atlantic. The sections were nominally perpendicular to the stream and measured in a Lagrangian frame by following a floating spar buoy drifting in the Gulf Stream’s warm core. During the survey, EDW was isolated from the mixed layer by the stratified seasonal pycnocline, suggesting that EDW was not yet actively being formed at this time in the season and at the longitudes over which the survey was conducted (64°–70°W). However, in two of the sections, the seasonal pycnocline in the core of the Gulf Stream was broken by an intrusion of cold, fresh, weakly stratified water, nearly saturated in oxygen, that appears to have been subducted from the surface mixed layer north of the stream. The intrusion was identified in three of the sections in profiles with a nearly identical temperature–salinity relation. From the western-to-easternmost sections, where the intrusion was observed, the depth of the intrusion’s salinity minimum descended by 90 m in the 71 h it took to complete this part of the survey. This apparent subduction occurred primarily on the upstream side of a meander trough, where the cross-stream velocity was confluent and frontogenetic. Using a variant of the omega equation, the vertical velocity driven by the confluent flow was inferred and yielded downwelling in the vicinity of the intrusion spanning 10–40 m day−1, a range of values consistent with the intrusion’s observed descent, suggesting that frontal subduction was responsible for the formation of the ... Article in Journal/Newspaper North Atlantic Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Journal of Physical Oceanography 40 2 429 438 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Ocean circulation Thermohaline circulation Frontogenesis/frontolysis |
spellingShingle |
Ocean circulation Thermohaline circulation Frontogenesis/frontolysis Thomas, Leif N. Joyce, Terrence M. Subduction on the northern and southern flanks of the Gulf Stream |
topic_facet |
Ocean circulation Thermohaline circulation Frontogenesis/frontolysis |
description |
Author Posting. © American Meteorological Society, 2010. 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 40 (2010): 429-438, doi:10.1175/2009JPO4187.1. Sections of temperature, salinity, dissolved oxygen, and velocity were made crossing the Gulf Stream in late January 2006 to investigate the role of frontal processes in the formation of Eighteen Degree Water (EDW), the Subtropical Mode Water of the North Atlantic. The sections were nominally perpendicular to the stream and measured in a Lagrangian frame by following a floating spar buoy drifting in the Gulf Stream’s warm core. During the survey, EDW was isolated from the mixed layer by the stratified seasonal pycnocline, suggesting that EDW was not yet actively being formed at this time in the season and at the longitudes over which the survey was conducted (64°–70°W). However, in two of the sections, the seasonal pycnocline in the core of the Gulf Stream was broken by an intrusion of cold, fresh, weakly stratified water, nearly saturated in oxygen, that appears to have been subducted from the surface mixed layer north of the stream. The intrusion was identified in three of the sections in profiles with a nearly identical temperature–salinity relation. From the western-to-easternmost sections, where the intrusion was observed, the depth of the intrusion’s salinity minimum descended by 90 m in the 71 h it took to complete this part of the survey. This apparent subduction occurred primarily on the upstream side of a meander trough, where the cross-stream velocity was confluent and frontogenetic. Using a variant of the omega equation, the vertical velocity driven by the confluent flow was inferred and yielded downwelling in the vicinity of the intrusion spanning 10–40 m day−1, a range of values consistent with the intrusion’s observed descent, suggesting that frontal subduction was responsible for the formation of the ... |
format |
Article in Journal/Newspaper |
author |
Thomas, Leif N. Joyce, Terrence M. |
author_facet |
Thomas, Leif N. Joyce, Terrence M. |
author_sort |
Thomas, Leif N. |
title |
Subduction on the northern and southern flanks of the Gulf Stream |
title_short |
Subduction on the northern and southern flanks of the Gulf Stream |
title_full |
Subduction on the northern and southern flanks of the Gulf Stream |
title_fullStr |
Subduction on the northern and southern flanks of the Gulf Stream |
title_full_unstemmed |
Subduction on the northern and southern flanks of the Gulf Stream |
title_sort |
subduction on the northern and southern flanks of the gulf stream |
publisher |
American Meteorological Society |
publishDate |
2010 |
url |
https://hdl.handle.net/1912/3957 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Journal of Physical Oceanography 40 (2010): 429-438 doi:10.1175/2009JPO4187.1 |
op_relation |
https://doi.org/10.1175/2009JPO4187.1 Journal of Physical Oceanography 40 (2010): 429-438 https://hdl.handle.net/1912/3957 doi:10.1175/2009JPO4187.1 |
op_doi |
https://doi.org/10.1175/2009JPO4187.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
40 |
container_issue |
2 |
container_start_page |
429 |
op_container_end_page |
438 |
_version_ |
1766135589943377920 |