Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography
Author Posting. © American Meteorological Society, 2008. 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 38 (2008): 104–120, doi:10.1175/2007JPO3686.1. Rece...
Published in: | Journal of Physical Oceanography |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Meteorological Society
2008
|
Subjects: | |
Online Access: | https://hdl.handle.net/1912/4035 |
id |
ftwhoas:oai:darchive.mblwhoilibrary.org:1912/4035 |
---|---|
record_format |
openpolar |
spelling |
ftwhoas:oai:darchive.mblwhoilibrary.org:1912/4035 2023-05-15T16:52:48+02:00 Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography Bower, Amy S. von Appen, Wilken-Jon 2008-01 application/pdf https://hdl.handle.net/1912/4035 en_US eng American Meteorological Society https://doi.org/10.1175/2007JPO3686.1 Journal of Physical Oceanography 38 (2008): 104–120 https://hdl.handle.net/1912/4035 doi:10.1175/2007JPO3686.1 Journal of Physical Oceanography 38 (2008): 104–120 doi:10.1175/2007JPO3686.1 Currents Topographic effects Interannual variability Forcing Gyres Article 2008 ftwhoas https://doi.org/10.1175/2007JPO3686.1 2022-05-28T22:58:09Z Author Posting. © American Meteorological Society, 2008. 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 38 (2008): 104–120, doi:10.1175/2007JPO3686.1. Recent studies have indicated that the North Atlantic Ocean subpolar gyre circulation undergoes significant interannual-to-decadal changes in response to variability in atmospheric forcing. There are also observations, however, suggesting that the southern limb of the subpolar gyre, namely, the eastward-flowing North Atlantic Current (NAC), may be quasi-locked to particular latitudes in the central North Atlantic by fracture zones (gaps) in the Mid-Atlantic Ridge. This could constrain the current’s ability to respond to variability in forcing. In the present study, subsurface float trajectories at 100–1000 m collected during 1997–99 and satellite-derived surface geostrophic velocities from 1992 to 2006 are used to provide an improved description of the detailed pathways of the NAC over the ridge and their relationship to bathymetry. Both the float and satellite observations indicate that in 1997–99, the northern branch of the NAC was split into two branches as it crossed the ridge, one quasi-locked to the Charlie–Gibbs Fracture Zone (CGFZ; 52°–53°N) and the other to the Faraday Fracture Zone (50°–51°N). The longer satellite time series shows, however, that this pattern did not persist outside the float sampling period and that other branching modes persisted for one or more years, including an approximately 12-month time period in 2002–03 when the strongest eastward flow over the ridge was at 49°N. Schott et al. showed how northward excursions of the NAC can temporarily block the westward flow of the Iceland–Scotland Overflow Water through the CGFZ. From the 13-yr time series of surface geostrophic velocity, it is estimated that such blocking may occur on average 6% of the time, although estimates for any given 12-month ... Article in Journal/Newspaper Iceland north atlantic current North Atlantic Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Faraday ENVELOPE(-64.256,-64.256,-65.246,-65.246) Faraday Fracture Zone ENVELOPE(-27.500,-27.500,49.500,49.500) Mid-Atlantic Ridge Schott ENVELOPE(-60.855,-60.855,-72.167,-72.167) Journal of Physical Oceanography 38 1 104 120 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Currents Topographic effects Interannual variability Forcing Gyres |
spellingShingle |
Currents Topographic effects Interannual variability Forcing Gyres Bower, Amy S. von Appen, Wilken-Jon Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography |
topic_facet |
Currents Topographic effects Interannual variability Forcing Gyres |
description |
Author Posting. © American Meteorological Society, 2008. 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 38 (2008): 104–120, doi:10.1175/2007JPO3686.1. Recent studies have indicated that the North Atlantic Ocean subpolar gyre circulation undergoes significant interannual-to-decadal changes in response to variability in atmospheric forcing. There are also observations, however, suggesting that the southern limb of the subpolar gyre, namely, the eastward-flowing North Atlantic Current (NAC), may be quasi-locked to particular latitudes in the central North Atlantic by fracture zones (gaps) in the Mid-Atlantic Ridge. This could constrain the current’s ability to respond to variability in forcing. In the present study, subsurface float trajectories at 100–1000 m collected during 1997–99 and satellite-derived surface geostrophic velocities from 1992 to 2006 are used to provide an improved description of the detailed pathways of the NAC over the ridge and their relationship to bathymetry. Both the float and satellite observations indicate that in 1997–99, the northern branch of the NAC was split into two branches as it crossed the ridge, one quasi-locked to the Charlie–Gibbs Fracture Zone (CGFZ; 52°–53°N) and the other to the Faraday Fracture Zone (50°–51°N). The longer satellite time series shows, however, that this pattern did not persist outside the float sampling period and that other branching modes persisted for one or more years, including an approximately 12-month time period in 2002–03 when the strongest eastward flow over the ridge was at 49°N. Schott et al. showed how northward excursions of the NAC can temporarily block the westward flow of the Iceland–Scotland Overflow Water through the CGFZ. From the 13-yr time series of surface geostrophic velocity, it is estimated that such blocking may occur on average 6% of the time, although estimates for any given 12-month ... |
format |
Article in Journal/Newspaper |
author |
Bower, Amy S. von Appen, Wilken-Jon |
author_facet |
Bower, Amy S. von Appen, Wilken-Jon |
author_sort |
Bower, Amy S. |
title |
Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography |
title_short |
Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography |
title_full |
Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography |
title_fullStr |
Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography |
title_full_unstemmed |
Interannual variability in the pathways of the North Atlantic Current over the Mid-Atlantic Ridge and the impact of topography |
title_sort |
interannual variability in the pathways of the north atlantic current over the mid-atlantic ridge and the impact of topography |
publisher |
American Meteorological Society |
publishDate |
2008 |
url |
https://hdl.handle.net/1912/4035 |
long_lat |
ENVELOPE(-64.256,-64.256,-65.246,-65.246) ENVELOPE(-27.500,-27.500,49.500,49.500) ENVELOPE(-60.855,-60.855,-72.167,-72.167) |
geographic |
Faraday Faraday Fracture Zone Mid-Atlantic Ridge Schott |
geographic_facet |
Faraday Faraday Fracture Zone Mid-Atlantic Ridge Schott |
genre |
Iceland north atlantic current North Atlantic |
genre_facet |
Iceland north atlantic current North Atlantic |
op_source |
Journal of Physical Oceanography 38 (2008): 104–120 doi:10.1175/2007JPO3686.1 |
op_relation |
https://doi.org/10.1175/2007JPO3686.1 Journal of Physical Oceanography 38 (2008): 104–120 https://hdl.handle.net/1912/4035 doi:10.1175/2007JPO3686.1 |
op_doi |
https://doi.org/10.1175/2007JPO3686.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
38 |
container_issue |
1 |
container_start_page |
104 |
op_container_end_page |
120 |
_version_ |
1766043232801652736 |