Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean
Coherent mesoscale features (referred to here as eddies) in the tropical northeast Atlantic (between 12–22° N and 15–26° W) are examined and characterised. The eddies' surface signatures are investigated using 19 years of satellite derived sea level anomaly (SLA) data. Two automated detection m...
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Copernicus Publications (EGU)
2016
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Online Access: | https://oceanrep.geomar.de/id/eprint/30689/ https://oceanrep.geomar.de/id/eprint/30689/1/os-12-663-2016.pdf https://doi.org/10.5194/os-12-663-2016 |
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ftoceanrep:oai:oceanrep.geomar.de:30689 2023-05-15T17:41:19+02:00 Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean Schütte, Florian Brandt, Peter Karstensen, Johannes 2016-05-13 text https://oceanrep.geomar.de/id/eprint/30689/ https://oceanrep.geomar.de/id/eprint/30689/1/os-12-663-2016.pdf https://doi.org/10.5194/os-12-663-2016 en eng Copernicus Publications (EGU) https://oceanrep.geomar.de/id/eprint/30689/1/os-12-663-2016.pdf Schütte, F., Brandt, P. and Karstensen, J. (2016) Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean. Open Access Ocean Science, 12 (3). pp. 663-685. DOI 10.5194/os-12-663-2016 <https://doi.org/10.5194/os-12-663-2016>. doi:10.5194/os-12-663-2016 cc_by_3.0 info:eu-repo/semantics/openAccess Article PeerReviewed 2016 ftoceanrep https://doi.org/10.5194/os-12-663-2016 2023-04-07T15:22:31Z Coherent mesoscale features (referred to here as eddies) in the tropical northeast Atlantic (between 12–22° N and 15–26° W) are examined and characterised. The eddies' surface signatures are investigated using 19 years of satellite derived sea level anomaly (SLA) data. Two automated detection methods are applied, the geometrical method based on closed streamlines around eddy cores, and the Okubo–Weiß method based on the relation between vorticity and strain. Both methods give similar results. Mean eddy surface signatures of SLA, sea surface temperature (SST) and salinity (SSS) are obtained from composites of all snapshots around identified eddy cores. Anticyclones/cyclones are associated with elevation/depression of SLA and enhanced/reduced SST and SSS patterns. However, about 20 % of all detected anticyclones show reduced SST and reduced SSS instead. These kind of eddies are classified as anticyclonic mode-water eddies (ACMEs). About 146 ± 4 eddies per year are identified (52 % cyclones, 39 % anticylones, 9 % ACMEs) with rather similar mean radii of about 56 ± 12 km. Based on concurrent in-situ temperature and salinity profile data (from Argo float, shipboard and mooring data) inside of the three eddy types, their distinct differences in vertical structure is determined. Most eddies are generated preferentially in boreal summer and along the West African coast at three distinct coastal headland region and carry South Atlantic Central Water that originates from the northward transport within the Mauretania coastal current system. Westward eddy propagation (on average about 3.00 ± 2.15 km d−1) is confined to distinct corridors with a small meridional deflection dependent on the eddy type (anticyclones – equatorward, cyclones – poleward, ACMEs – no deflection). Heat and salt flux out of the coastal region and across the Cap Verde Frontal Zone, which separates the shadow zone from the ventilated gyre, are calculated. Article in Journal/Newspaper Northeast Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Ocean Science 12 3 663 685 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
Coherent mesoscale features (referred to here as eddies) in the tropical northeast Atlantic (between 12–22° N and 15–26° W) are examined and characterised. The eddies' surface signatures are investigated using 19 years of satellite derived sea level anomaly (SLA) data. Two automated detection methods are applied, the geometrical method based on closed streamlines around eddy cores, and the Okubo–Weiß method based on the relation between vorticity and strain. Both methods give similar results. Mean eddy surface signatures of SLA, sea surface temperature (SST) and salinity (SSS) are obtained from composites of all snapshots around identified eddy cores. Anticyclones/cyclones are associated with elevation/depression of SLA and enhanced/reduced SST and SSS patterns. However, about 20 % of all detected anticyclones show reduced SST and reduced SSS instead. These kind of eddies are classified as anticyclonic mode-water eddies (ACMEs). About 146 ± 4 eddies per year are identified (52 % cyclones, 39 % anticylones, 9 % ACMEs) with rather similar mean radii of about 56 ± 12 km. Based on concurrent in-situ temperature and salinity profile data (from Argo float, shipboard and mooring data) inside of the three eddy types, their distinct differences in vertical structure is determined. Most eddies are generated preferentially in boreal summer and along the West African coast at three distinct coastal headland region and carry South Atlantic Central Water that originates from the northward transport within the Mauretania coastal current system. Westward eddy propagation (on average about 3.00 ± 2.15 km d−1) is confined to distinct corridors with a small meridional deflection dependent on the eddy type (anticyclones – equatorward, cyclones – poleward, ACMEs – no deflection). Heat and salt flux out of the coastal region and across the Cap Verde Frontal Zone, which separates the shadow zone from the ventilated gyre, are calculated. |
format |
Article in Journal/Newspaper |
author |
Schütte, Florian Brandt, Peter Karstensen, Johannes |
spellingShingle |
Schütte, Florian Brandt, Peter Karstensen, Johannes Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean |
author_facet |
Schütte, Florian Brandt, Peter Karstensen, Johannes |
author_sort |
Schütte, Florian |
title |
Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean |
title_short |
Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean |
title_full |
Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean |
title_fullStr |
Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean |
title_full_unstemmed |
Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean |
title_sort |
occurrence and characteristics of mesoscale eddies in the tropical northeast atlantic ocean |
publisher |
Copernicus Publications (EGU) |
publishDate |
2016 |
url |
https://oceanrep.geomar.de/id/eprint/30689/ https://oceanrep.geomar.de/id/eprint/30689/1/os-12-663-2016.pdf https://doi.org/10.5194/os-12-663-2016 |
genre |
Northeast Atlantic |
genre_facet |
Northeast Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/30689/1/os-12-663-2016.pdf Schütte, F., Brandt, P. and Karstensen, J. (2016) Occurrence and characteristics of mesoscale eddies in the tropical northeast Atlantic Ocean. Open Access Ocean Science, 12 (3). pp. 663-685. DOI 10.5194/os-12-663-2016 <https://doi.org/10.5194/os-12-663-2016>. doi:10.5194/os-12-663-2016 |
op_rights |
cc_by_3.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/os-12-663-2016 |
container_title |
Ocean Science |
container_volume |
12 |
container_issue |
3 |
container_start_page |
663 |
op_container_end_page |
685 |
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1766142796425592832 |