Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system

 

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dc.contributor.advisor Rouault, Mathieu en_ZA
dc.contributor.advisor Veitch, Jennifer Anne en_ZA
dc.contributor.author Yates, Sarah Elizabeth en_ZA
dc.date.accessioned 2014-11-28T09:55:09Z
dc.date.available 2014-11-28T09:55:09Z
dc.date.issued 2012 en_ZA
dc.identifier.citation Yates, S. 2012. Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/9808
dc.description Includes bibliographical references. en_ZA
dc.description.abstract The Benguela Current System is unique as both the equatorward and poleward boundaries are warm water current systems. Between 15° S – 37° S the surface currents are generally equatorwards, with 7 distinct upwelling cells, narrow equatorward shelf-edge jets and a poleward undercurrent along the continental slope. Model data was used to determine the seasonal and interannual variability of the poleward undercurrent (PUC) in the northern Benguela system. The PUC is the southward extension of the Angolan Current that carries low oxygen water (LOW) originating from the Angola Dome. The LOW flows from the Angolan region southwards in the Benguela system. The focus of the study is on the PUC associated with the Sverdrup relation. The model ORCA-025 was used to reproduce zonal transects from 17° S to 30° S to determine the changing characteristics of the PUC with latitude as well as seasonal and interannual variability of this current. The PUC is faster moving in the north (~17° S) and decreases in velocity moving south (~30° S). The PUC is shallower in the north increasing in depth in the south. The model data shows the velocity of the PUC has a seasonal cycle that is faster in the austral summer and autumn and weakens in the winter. The transport of the PUC is amplified during austral winter and spring, which is consistent with the increased negative wind stress curl during those seasons. The wind stress curl in the region exhibits a strong connection with the transport of the PUC via the Sverdrup relation. The PUC exhibits interannual variability when comparing to the Benguela Niño events, but does not show a correlation with El Niño Southern Oscillation. en_ZA
dc.language.iso eng en_ZA
dc.title Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Oceanography en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Yates, S. E. (2012). <i>Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Oceanography. Retrieved from http://hdl.handle.net/11427/9808 en_ZA
dc.identifier.chicagocitation Yates, Sarah Elizabeth. <i>"Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Oceanography, 2012. http://hdl.handle.net/11427/9808 en_ZA
dc.identifier.vancouvercitation Yates SE. Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Oceanography, 2012 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9808 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Yates, Sarah Elizabeth AB - The Benguela Current System is unique as both the equatorward and poleward boundaries are warm water current systems. Between 15° S – 37° S the surface currents are generally equatorwards, with 7 distinct upwelling cells, narrow equatorward shelf-edge jets and a poleward undercurrent along the continental slope. Model data was used to determine the seasonal and interannual variability of the poleward undercurrent (PUC) in the northern Benguela system. The PUC is the southward extension of the Angolan Current that carries low oxygen water (LOW) originating from the Angola Dome. The LOW flows from the Angolan region southwards in the Benguela system. The focus of the study is on the PUC associated with the Sverdrup relation. The model ORCA-025 was used to reproduce zonal transects from 17° S to 30° S to determine the changing characteristics of the PUC with latitude as well as seasonal and interannual variability of this current. The PUC is faster moving in the north (~17° S) and decreases in velocity moving south (~30° S). The PUC is shallower in the north increasing in depth in the south. The model data shows the velocity of the PUC has a seasonal cycle that is faster in the austral summer and autumn and weakens in the winter. The transport of the PUC is amplified during austral winter and spring, which is consistent with the increased negative wind stress curl during those seasons. The wind stress curl in the region exhibits a strong connection with the transport of the PUC via the Sverdrup relation. The PUC exhibits interannual variability when comparing to the Benguela Niño events, but does not show a correlation with El Niño Southern Oscillation. DA - 2012 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2012 T1 - Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system TI - Investigating the seasonal and interannual variability of the poleward undercurrent in the northern Benguela system UR - http://hdl.handle.net/11427/9808 ER - en_ZA


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