Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic
A total of 21 about year‐long current meter records in the depth range of the upper and middle North Atlantic Deep Water (NADW) were analyzed to determine the mean and the fluctuations of the upper Deep Western Boundary Current (DWBC) in the equatorial Atlantic. The investigation was based on moored...
Published in: | Journal of Geophysical Research: Oceans |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
AGU (American Geophysical Union)
1997
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/5558/ https://oceanrep.geomar.de/id/eprint/5558/1/Fischer_et_al-1997-Journal_of_Geophysical_Research__Oceans_%281978-2012%29.pdf https://doi.org/10.1029/97JC02327 |
id |
ftoceanrep:oai:oceanrep.geomar.de:5558 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:5558 2023-05-15T17:13:51+02:00 Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic Fischer, Jürgen Schott, Friedrich 1997 text https://oceanrep.geomar.de/id/eprint/5558/ https://oceanrep.geomar.de/id/eprint/5558/1/Fischer_et_al-1997-Journal_of_Geophysical_Research__Oceans_%281978-2012%29.pdf https://doi.org/10.1029/97JC02327 en eng AGU (American Geophysical Union) https://oceanrep.geomar.de/id/eprint/5558/1/Fischer_et_al-1997-Journal_of_Geophysical_Research__Oceans_%281978-2012%29.pdf Fischer, J. and Schott, F. (1997) Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic. Open Access Journal of Geophysical Research: Oceans, 102 (C13). 27,751-27,769. DOI 10.1029/97JC02327 <https://doi.org/10.1029/97JC02327>. doi:10.1029/97JC02327 info:eu-repo/semantics/openAccess Article PeerReviewed 1997 ftoceanrep https://doi.org/10.1029/97JC02327 2023-04-07T14:51:12Z A total of 21 about year‐long current meter records in the depth range of the upper and middle North Atlantic Deep Water (NADW) were analyzed to determine the mean and the fluctuations of the upper Deep Western Boundary Current (DWBC) in the equatorial Atlantic. The investigation was based on moored arrays at 44°W from three different deployment periods, 1989/1990, 1990/1991 and 1992/1994, and was supplemented by current profiling along 44°W and 35°W. The approximately 100‐km‐wide DWBC at 44°W, just north of the equator, was attached to the topography with the current maximum exceeding 70 cm s−1. Currents within the DWBC core followed the topography, and the close agreement between the mean current direction and the direction of maximum variance indicated that the major contribution to the DWBC variability near the equator was due to pulsing rather than meandering. For mean transports of upper and middle NADW, the current meter records were averaged over their deployment duration yielding a best estimate of 13 Sv in the depth range 1000 to 3100 m. The mean transport appeared robust, as subsets of the data from two different years yielded about the same mean transport, namely, 12.4 and 13.6 Sv. The DWBC transport time series showed a definite seasonal cycle, ranging from less than 7 Sv during September/October to about 25 Sv during January/February. Annual and semiannual transport harmonics had similar amplitudes, at about 6 Sv each, and together they explained about two thirds of the total transport variability. After crossing the equator, the DWBC splits into two cores with the major flow along a chain of seamounts near 3.5°S, near 35°W. Magnitudes and phases of the transport variability at 35°W, south of approximately 1.5°S, were similar to that at 44°W. Further, for the flow of lower NADW which was detached from the upper DWBC core, similar periodicity and phases were observed in the deep records at 44°W. Article in Journal/Newspaper NADW North Atlantic Deep Water North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Journal of Geophysical Research: Oceans 102 C13 27751 27769 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
A total of 21 about year‐long current meter records in the depth range of the upper and middle North Atlantic Deep Water (NADW) were analyzed to determine the mean and the fluctuations of the upper Deep Western Boundary Current (DWBC) in the equatorial Atlantic. The investigation was based on moored arrays at 44°W from three different deployment periods, 1989/1990, 1990/1991 and 1992/1994, and was supplemented by current profiling along 44°W and 35°W. The approximately 100‐km‐wide DWBC at 44°W, just north of the equator, was attached to the topography with the current maximum exceeding 70 cm s−1. Currents within the DWBC core followed the topography, and the close agreement between the mean current direction and the direction of maximum variance indicated that the major contribution to the DWBC variability near the equator was due to pulsing rather than meandering. For mean transports of upper and middle NADW, the current meter records were averaged over their deployment duration yielding a best estimate of 13 Sv in the depth range 1000 to 3100 m. The mean transport appeared robust, as subsets of the data from two different years yielded about the same mean transport, namely, 12.4 and 13.6 Sv. The DWBC transport time series showed a definite seasonal cycle, ranging from less than 7 Sv during September/October to about 25 Sv during January/February. Annual and semiannual transport harmonics had similar amplitudes, at about 6 Sv each, and together they explained about two thirds of the total transport variability. After crossing the equator, the DWBC splits into two cores with the major flow along a chain of seamounts near 3.5°S, near 35°W. Magnitudes and phases of the transport variability at 35°W, south of approximately 1.5°S, were similar to that at 44°W. Further, for the flow of lower NADW which was detached from the upper DWBC core, similar periodicity and phases were observed in the deep records at 44°W. |
format |
Article in Journal/Newspaper |
author |
Fischer, Jürgen Schott, Friedrich |
spellingShingle |
Fischer, Jürgen Schott, Friedrich Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic |
author_facet |
Fischer, Jürgen Schott, Friedrich |
author_sort |
Fischer, Jürgen |
title |
Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic |
title_short |
Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic |
title_full |
Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic |
title_fullStr |
Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic |
title_full_unstemmed |
Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic |
title_sort |
seasonal transport variability of the deep western boundary current in the equatorial atlantic |
publisher |
AGU (American Geophysical Union) |
publishDate |
1997 |
url |
https://oceanrep.geomar.de/id/eprint/5558/ https://oceanrep.geomar.de/id/eprint/5558/1/Fischer_et_al-1997-Journal_of_Geophysical_Research__Oceans_%281978-2012%29.pdf https://doi.org/10.1029/97JC02327 |
genre |
NADW North Atlantic Deep Water North Atlantic |
genre_facet |
NADW North Atlantic Deep Water North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/5558/1/Fischer_et_al-1997-Journal_of_Geophysical_Research__Oceans_%281978-2012%29.pdf Fischer, J. and Schott, F. (1997) Seasonal transport variability of the Deep Western Boundary Current in the equatorial Atlantic. Open Access Journal of Geophysical Research: Oceans, 102 (C13). 27,751-27,769. DOI 10.1029/97JC02327 <https://doi.org/10.1029/97JC02327>. doi:10.1029/97JC02327 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/97JC02327 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
102 |
container_issue |
C13 |
container_start_page |
27751 |
op_container_end_page |
27769 |
_version_ |
1766071046079774720 |