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Agulhas retroflection rings in the South Atlantic Ocean
The western boundary current rings shed from the Agulhas retroflection may be responsible for a considerable transfer of heat, salt and energy from the South Indian into the South Atlantic Ocean. Few hydrographic measurements have been collected from Agulhas rings in the South Atlantic Ocean and the...
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| Format: | Thesis |
| Language: | English |
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Department of Oceanography
2016
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| _version_ | 1867613202886426624 |
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| access_status_str | Open Access |
| author | Duncombe Rae, Christopher Michael |
| author2 | Shillington, Frank A |
| author_browse | Duncombe Rae, Christopher Michael Shillington, Frank A |
| author_facet | Shillington, Frank A Duncombe Rae, Christopher Michael |
| author_sort | Duncombe Rae, Christopher Michael |
| collection | Thesis |
| description | The western boundary current rings shed from the Agulhas retroflection may be responsible for a considerable transfer of heat, salt and energy from the South Indian into the South Atlantic Ocean. Few hydrographic measurements have been collected from Agulhas rings in the South Atlantic Ocean and their characteristics and influence on the waters of the Cape Basin through which they pass are thus little known. The temperature, salinity, and nutrient data presented in the thesis were collected from three Agulhas rings on a number of recent hydrographic cruises in the South Atlantic Ocean. Temperature profiles, conductivity-temperature-depth measurements, nutrient data, GEOSAT altimeter data, and NOAA-11 satellite imagery were used to investigate one of the rings in May 1989. It had previously been postulated that the rings could have an important effect on the Benguela upwelling system and this thesis demonstrates the interaction of the ring with a filament from the upwelling system. An adverse influence of this interaction on the anchovy larval population is postulated, and cited as a possible cause of the very poor anchovy yearclass of 1989. The other two rings were encountered during winter (August 1990 and June 1992), closer to the retroflection, and only hydrographic observations were possible. One of the rings showed a very deep isothermal surface layer and evidence of a deep pycnostad at its centre. The deep stad is shown to be likely due to vortex stretching and possible sources for the water in the stad are suggested. Comparative hydrographic characteristics, water mass structure, velocity fields, and the potential for contribution to interbasin transfer of the three rings are presented and discussed in the thesis. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/18340 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:24.523Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Oceanography |
| publisherStr | Department of Oceanography |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/18340 Agulhas retroflection rings in the South Atlantic Ocean Duncombe Rae, Christopher Michael Shillington, Frank A Oceanography The western boundary current rings shed from the Agulhas retroflection may be responsible for a considerable transfer of heat, salt and energy from the South Indian into the South Atlantic Ocean. Few hydrographic measurements have been collected from Agulhas rings in the South Atlantic Ocean and their characteristics and influence on the waters of the Cape Basin through which they pass are thus little known. The temperature, salinity, and nutrient data presented in the thesis were collected from three Agulhas rings on a number of recent hydrographic cruises in the South Atlantic Ocean. Temperature profiles, conductivity-temperature-depth measurements, nutrient data, GEOSAT altimeter data, and NOAA-11 satellite imagery were used to investigate one of the rings in May 1989. It had previously been postulated that the rings could have an important effect on the Benguela upwelling system and this thesis demonstrates the interaction of the ring with a filament from the upwelling system. An adverse influence of this interaction on the anchovy larval population is postulated, and cited as a possible cause of the very poor anchovy yearclass of 1989. The other two rings were encountered during winter (August 1990 and June 1992), closer to the retroflection, and only hydrographic observations were possible. One of the rings showed a very deep isothermal surface layer and evidence of a deep pycnostad at its centre. The deep stad is shown to be likely due to vortex stretching and possible sources for the water in the stad are suggested. Comparative hydrographic characteristics, water mass structure, velocity fields, and the potential for contribution to interbasin transfer of the three rings are presented and discussed in the thesis. 2016-03-28T14:44:33Z 2016-03-28T14:44:33Z 1994 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/18340 eng application/pdf Department of Oceanography Faculty of Science University of Cape Town |
| spellingShingle | Oceanography Duncombe Rae, Christopher Michael Agulhas retroflection rings in the South Atlantic Ocean |
| thesis_degree_str | Doctoral |
| title | Agulhas retroflection rings in the South Atlantic Ocean |
| title_full | Agulhas retroflection rings in the South Atlantic Ocean |
| title_fullStr | Agulhas retroflection rings in the South Atlantic Ocean |
| title_full_unstemmed | Agulhas retroflection rings in the South Atlantic Ocean |
| title_short | Agulhas retroflection rings in the South Atlantic Ocean |
| title_sort | agulhas retroflection rings in the south atlantic ocean |
| topic | Oceanography |
| url | http://hdl.handle.net/11427/18340 |
| work_keys_str_mv | AT duncomberaechristophermichael agulhasretroflectionringsinthesouthatlanticocean |