Numerical simulation of a mesoscale convective system over the east coast of South Africa

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dc.contributor.advisorReason, Chrisen_ZA
dc.contributor.authorBlamey, Rossen_ZA
dc.date.accessioned2014-08-13T19:48:25Z
dc.date.available2014-08-13T19:48:25Z
dc.date.issued2007en_ZA
dc.descriptionIncludes bibliographical references (leaves 189-200).en_ZA
dc.description.abstractWeather stations across the northern KwaZulu-Natal coastline recorded over 100 mm of rainfall over the 11112 February 2005, with Cape St. Lucia and Richards Bay measuring 111 mm and 96.8 mm, respectively. This heavy rainfall was associated with a mesoscale convective system (MCS) that initiated through small convective storms beginning early in the afternoon on 11 February 2005 and eventually decayed in the early morning hours on the 12th. The high-lying topography of the eastern escarpment and high diurnal surface heating possibly provided the trigger for the event. It was also identified that a combination of synoptic features in and around South Africa contributed to the evolution of the system. This particular MCS is investigated with a non-hydrostatic numerical model (MM5) to help determine which processes were important in its initiation and development, as well as what factors contributed to the associated heavy rainfall. The model is also used to conduct sensitivity tests to determine the role that local features, such as the regional topography and sea surface temperature, played in the evolution of the system. Through the various MM5 simulations, it was evident that the eastern escarpment played a key role in triggering the convective event, while it also had an influence on the low level winds that advected moisture into the region. A sea surface temperature sensitivity simulation highlighted the important role that the Agulhas Current plays in supplying moisture to fuel extreme precipitation events in South Africa. The significance of resolving large-scale features in the mid-latitudes in numerical simulations of weather events in South Africa was identified when excluding these features from the simulation. Through these simulations it was identified that the development of the MCS and the heavy nocturnal precipitation was due to a combination of the continuous moisture supply into the region, a conditionally unstable atmosphere, and uplift due to low level convergence and the local topography.en_ZA
dc.identifier.apacitationBlamey, R. (2007). <i>Numerical simulation of a mesoscale convective system over the east coast of South Africa</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Oceanography. Retrieved from http://hdl.handle.net/11427/6463en_ZA
dc.identifier.chicagocitationBlamey, Ross. <i>"Numerical simulation of a mesoscale convective system over the east coast of South Africa."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Oceanography, 2007. http://hdl.handle.net/11427/6463en_ZA
dc.identifier.citationBlamey, R. 2007. Numerical simulation of a mesoscale convective system over the east coast of South Africa. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Blamey, Ross AB - Weather stations across the northern KwaZulu-Natal coastline recorded over 100 mm of rainfall over the 11112 February 2005, with Cape St. Lucia and Richards Bay measuring 111 mm and 96.8 mm, respectively. This heavy rainfall was associated with a mesoscale convective system (MCS) that initiated through small convective storms beginning early in the afternoon on 11 February 2005 and eventually decayed in the early morning hours on the 12th. The high-lying topography of the eastern escarpment and high diurnal surface heating possibly provided the trigger for the event. It was also identified that a combination of synoptic features in and around South Africa contributed to the evolution of the system. This particular MCS is investigated with a non-hydrostatic numerical model (MM5) to help determine which processes were important in its initiation and development, as well as what factors contributed to the associated heavy rainfall. The model is also used to conduct sensitivity tests to determine the role that local features, such as the regional topography and sea surface temperature, played in the evolution of the system. Through the various MM5 simulations, it was evident that the eastern escarpment played a key role in triggering the convective event, while it also had an influence on the low level winds that advected moisture into the region. A sea surface temperature sensitivity simulation highlighted the important role that the Agulhas Current plays in supplying moisture to fuel extreme precipitation events in South Africa. The significance of resolving large-scale features in the mid-latitudes in numerical simulations of weather events in South Africa was identified when excluding these features from the simulation. Through these simulations it was identified that the development of the MCS and the heavy nocturnal precipitation was due to a combination of the continuous moisture supply into the region, a conditionally unstable atmosphere, and uplift due to low level convergence and the local topography. DA - 2007 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2007 T1 - Numerical simulation of a mesoscale convective system over the east coast of South Africa TI - Numerical simulation of a mesoscale convective system over the east coast of South Africa UR - http://hdl.handle.net/11427/6463 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/6463
dc.identifier.vancouvercitationBlamey R. Numerical simulation of a mesoscale convective system over the east coast of South Africa. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Oceanography, 2007 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/6463en_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.titleNumerical simulation of a mesoscale convective system over the east coast of South Africaen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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