Agulhas retroflection rings in the South Atlantic Ocean

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dc.contributor.advisorShillington, Frank Aen_ZA
dc.contributor.authorDuncombe Rae, Christopher Michaelen_ZA
dc.date.accessioned2016-03-28T14:44:33Z
dc.date.available2016-03-28T14:44:33Z
dc.date.issued1994en_ZA
dc.description.abstractThe 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.en_ZA
dc.identifier.apacitationDuncombe Rae, C. M. (1994). <i>Agulhas retroflection rings in the South Atlantic Ocean</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Oceanography. Retrieved from http://hdl.handle.net/11427/18340en_ZA
dc.identifier.chicagocitationDuncombe Rae, Christopher Michael. <i>"Agulhas retroflection rings in the South Atlantic Ocean."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Oceanography, 1994. http://hdl.handle.net/11427/18340en_ZA
dc.identifier.citationDuncombe Rae, C. 1994. Agulhas retroflection rings in the South Atlantic Ocean. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Duncombe Rae, Christopher Michael AB - 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. DA - 1994 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1994 T1 - Agulhas retroflection rings in the South Atlantic Ocean TI - Agulhas retroflection rings in the South Atlantic Ocean UR - http://hdl.handle.net/11427/18340 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/18340
dc.identifier.vancouvercitationDuncombe Rae CM. Agulhas retroflection rings in the South Atlantic Ocean. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Oceanography, 1994 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/18340en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Oceanographyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherOceanographyen_ZA
dc.titleAgulhas retroflection rings in the South Atlantic Oceanen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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