The shallow and deep western boundary circulation of the South Atlantic at 5-11°S
Repeated shipboard observation sections across the boundary flow off northeastern Brazil as well as acoustic Doppler current profiler (ADCP) and current-meter records from a moored boundary array deployed during 2000–04 near 11°S are analyzed here for both the northward warm water flow by the North...
Published in: | Journal of Physical Oceanography |
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Language: | English |
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AMS (American Meteorological Society)
2005
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Online Access: | https://oceanrep.geomar.de/id/eprint/7363/ https://oceanrep.geomar.de/id/eprint/7363/1/JPO2813.pdf https://doi.org/10.1175/JPO2813.1 |
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ftoceanrep:oai:oceanrep.geomar.de:7363 2023-05-15T13:31:43+02:00 The shallow and deep western boundary circulation of the South Atlantic at 5-11°S Schott, Friedrich Dengler, Marcus Zantopp, Rainer J. Stramma, Lothar Fischer, Jürgen Brandt, Peter 2005 text https://oceanrep.geomar.de/id/eprint/7363/ https://oceanrep.geomar.de/id/eprint/7363/1/JPO2813.pdf https://doi.org/10.1175/JPO2813.1 en eng AMS (American Meteorological Society) https://oceanrep.geomar.de/id/eprint/7363/1/JPO2813.pdf Schott, F., Dengler, M. , Zantopp, R. J. , Stramma, L. , Fischer, J. and Brandt, P. (2005) The shallow and deep western boundary circulation of the South Atlantic at 5-11°S. Open Access Journal of Physical Oceanography, 35 . pp. 2031-2053. DOI 10.1175/JPO2813.1 <https://doi.org/10.1175/JPO2813.1>. doi:10.1175/JPO2813.1 info:eu-repo/semantics/openAccess Article PeerReviewed 2005 ftoceanrep https://doi.org/10.1175/JPO2813.1 2023-04-07T14:54:32Z Repeated shipboard observation sections across the boundary flow off northeastern Brazil as well as acoustic Doppler current profiler (ADCP) and current-meter records from a moored boundary array deployed during 2000–04 near 11°S are analyzed here for both the northward warm water flow by the North Brazil Undercurrent (NBUC) above approximately 1100 m and the southward flow of North Atlantic Deep Water (NADW) underneath. At 5°S, the mean from nine sections yields an NBUC transport of 26.5 ± 3.7 Sv (Sv ≡ 106 m3 s−1) along the boundary; at 11°S the mean NBUC transport from five sections is 25.4 ± 7.4 Sv, confirming that the NBUC is already well developed at 11°S. At both latitudes a persistent offshore southward recirculation between 200- and 1100-m depth reduces the net northward warm water flow through the 5°S section (west of 31.5°W) to 22.1 ± 5.3 Sv and through the 11°S section to 21.7 ± 4.1 Sv (west of 32.0°W). The 4-yr-long NBUC transport time series from 11°S yields a seasonal cycle of 2.5 Sv amplitude with its northward maximum in July. Interannual NBUC transport variations are small, varying only by ±1.2 Sv during the four years, with no detectable trend. The southward flow of NADW within the deep western boundary current at 5°S is 25.5 ± 8.3 Sv with an offshore northward recirculation, yielding a nine-section mean of 20.3 ± 10.1 Sv west of 31.5°W. For Antarctic Bottom Water, a net northward flow of 4.4 ± 3.0 Sv is determined at 5°S. For the 11°S section, the moored array data show a pronounced energy maximum at 60–70-day period in the NADW depth range, which was identified in related work as deep eddies translating southward along the boundary. Based on a kinematic eddy model fit to the first half of the moored time series, the mean NADW transfer by the deep eddies at 11°S was estimated to be about 17 Sv. Given the large interannual variability of the deep near-boundary transport time series, which ranged from 14 to 24 Sv, the 11°S mean was considered to be not distinguishable from the mean at 5°S Article in Journal/Newspaper Antarc* Antarctic NADW North Atlantic Deep Water North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic Journal of Physical Oceanography 35 11 2031 2053 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Repeated shipboard observation sections across the boundary flow off northeastern Brazil as well as acoustic Doppler current profiler (ADCP) and current-meter records from a moored boundary array deployed during 2000–04 near 11°S are analyzed here for both the northward warm water flow by the North Brazil Undercurrent (NBUC) above approximately 1100 m and the southward flow of North Atlantic Deep Water (NADW) underneath. At 5°S, the mean from nine sections yields an NBUC transport of 26.5 ± 3.7 Sv (Sv ≡ 106 m3 s−1) along the boundary; at 11°S the mean NBUC transport from five sections is 25.4 ± 7.4 Sv, confirming that the NBUC is already well developed at 11°S. At both latitudes a persistent offshore southward recirculation between 200- and 1100-m depth reduces the net northward warm water flow through the 5°S section (west of 31.5°W) to 22.1 ± 5.3 Sv and through the 11°S section to 21.7 ± 4.1 Sv (west of 32.0°W). The 4-yr-long NBUC transport time series from 11°S yields a seasonal cycle of 2.5 Sv amplitude with its northward maximum in July. Interannual NBUC transport variations are small, varying only by ±1.2 Sv during the four years, with no detectable trend. The southward flow of NADW within the deep western boundary current at 5°S is 25.5 ± 8.3 Sv with an offshore northward recirculation, yielding a nine-section mean of 20.3 ± 10.1 Sv west of 31.5°W. For Antarctic Bottom Water, a net northward flow of 4.4 ± 3.0 Sv is determined at 5°S. For the 11°S section, the moored array data show a pronounced energy maximum at 60–70-day period in the NADW depth range, which was identified in related work as deep eddies translating southward along the boundary. Based on a kinematic eddy model fit to the first half of the moored time series, the mean NADW transfer by the deep eddies at 11°S was estimated to be about 17 Sv. Given the large interannual variability of the deep near-boundary transport time series, which ranged from 14 to 24 Sv, the 11°S mean was considered to be not distinguishable from the mean at 5°S |
format |
Article in Journal/Newspaper |
author |
Schott, Friedrich Dengler, Marcus Zantopp, Rainer J. Stramma, Lothar Fischer, Jürgen Brandt, Peter |
spellingShingle |
Schott, Friedrich Dengler, Marcus Zantopp, Rainer J. Stramma, Lothar Fischer, Jürgen Brandt, Peter The shallow and deep western boundary circulation of the South Atlantic at 5-11°S |
author_facet |
Schott, Friedrich Dengler, Marcus Zantopp, Rainer J. Stramma, Lothar Fischer, Jürgen Brandt, Peter |
author_sort |
Schott, Friedrich |
title |
The shallow and deep western boundary circulation of the South Atlantic at 5-11°S |
title_short |
The shallow and deep western boundary circulation of the South Atlantic at 5-11°S |
title_full |
The shallow and deep western boundary circulation of the South Atlantic at 5-11°S |
title_fullStr |
The shallow and deep western boundary circulation of the South Atlantic at 5-11°S |
title_full_unstemmed |
The shallow and deep western boundary circulation of the South Atlantic at 5-11°S |
title_sort |
shallow and deep western boundary circulation of the south atlantic at 5-11°s |
publisher |
AMS (American Meteorological Society) |
publishDate |
2005 |
url |
https://oceanrep.geomar.de/id/eprint/7363/ https://oceanrep.geomar.de/id/eprint/7363/1/JPO2813.pdf https://doi.org/10.1175/JPO2813.1 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic NADW North Atlantic Deep Water North Atlantic |
genre_facet |
Antarc* Antarctic NADW North Atlantic Deep Water North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/7363/1/JPO2813.pdf Schott, F., Dengler, M. , Zantopp, R. J. , Stramma, L. , Fischer, J. and Brandt, P. (2005) The shallow and deep western boundary circulation of the South Atlantic at 5-11°S. Open Access Journal of Physical Oceanography, 35 . pp. 2031-2053. DOI 10.1175/JPO2813.1 <https://doi.org/10.1175/JPO2813.1>. doi:10.1175/JPO2813.1 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/JPO2813.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
35 |
container_issue |
11 |
container_start_page |
2031 |
op_container_end_page |
2053 |
_version_ |
1766020557035274240 |