Climatic trends and soil moisture feedbacks over Zimbabwe

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dc.contributor.advisorHewitson, Bruceen_ZA
dc.contributor.advisorTadross, Marken_ZA
dc.contributor.authorMdoka, Marshall Lisonen_ZA
dc.date.accessioned2014-07-31T07:59:03Z
dc.date.available2014-07-31T07:59:03Z
dc.date.issued2005en_ZA
dc.descriptionIncludes bibliographical references (leaves 106-118).
dc.description.abstractThe research focuses on an objective analysis of austral summer rainfall variability over Zimbabwe as well as characterization of rainfall patterns and frequency analysis over southern Africa region. A statistical analysis of historical trends in climate extreme events is used and lays a foundation of projecting into future climates. A trend analysis done on rainfall patterns attained from SOMs approach compliments the RClimdex statistical approach and strengthens some of the historical trends findings on climate extremes. Thereafter, some exploratory research seeks to explain the trends observed using the land-atmosphere interactions and shows the response of rainfall to anomalous soil moisture conditions during an extreme wet and dry seasons using RegCM3. Finally, some radiation effects results are presented from these soil moisture perturbations experiments. Results show drying out patterns over the region from the historical records analysed. The trend analysis done with SOM arrays revealed a positive trend towards drier conditions and a negative trend for wet conditions. The climate extremes indices analysis complimented these findings as shown in the decrease in total precipitation and an increase in the number of dry spells. This is supported by the circulation patterns showing an increase in frequency of the 500hPa anticyclones and a decrease of low pressures. However, some high altitude stations showed an intensification of precipitation events. This would exacerbate need for proper planning of future water resource management and farming strategies. Soil moisture rainfall feedback mechanisms were not fully explored. However drier conditions experiments showed a stronger response to soil moisture perturbations than in wetter conditions experiments. No consistent response to soil moisture initialisation over southern Africa was found. The altitude does modulate these feedback mechanisms with low-lying areas depicting a stronger response. A better understanding of the observed rainfall patterns, historical climate trends and soil moisture-rainfall feedback mechanisms are essential for improved short-term and seasonal forecasting and will aid the generation of plausible climate change impact predictions.en_ZA
dc.identifier.apacitationMdoka, M. L. (2005). <i>Climatic trends and soil moisture feedbacks over Zimbabwe</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Environmental and Geographical Science. Retrieved from http://hdl.handle.net/11427/4783en_ZA
dc.identifier.chicagocitationMdoka, Marshall Lison. <i>"Climatic trends and soil moisture feedbacks over Zimbabwe."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Environmental and Geographical Science, 2005. http://hdl.handle.net/11427/4783en_ZA
dc.identifier.citationMdoka, M. 2005. Climatic trends and soil moisture feedbacks over Zimbabwe. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Mdoka, Marshall Lison AB - The research focuses on an objective analysis of austral summer rainfall variability over Zimbabwe as well as characterization of rainfall patterns and frequency analysis over southern Africa region. A statistical analysis of historical trends in climate extreme events is used and lays a foundation of projecting into future climates. A trend analysis done on rainfall patterns attained from SOMs approach compliments the RClimdex statistical approach and strengthens some of the historical trends findings on climate extremes. Thereafter, some exploratory research seeks to explain the trends observed using the land-atmosphere interactions and shows the response of rainfall to anomalous soil moisture conditions during an extreme wet and dry seasons using RegCM3. Finally, some radiation effects results are presented from these soil moisture perturbations experiments. Results show drying out patterns over the region from the historical records analysed. The trend analysis done with SOM arrays revealed a positive trend towards drier conditions and a negative trend for wet conditions. The climate extremes indices analysis complimented these findings as shown in the decrease in total precipitation and an increase in the number of dry spells. This is supported by the circulation patterns showing an increase in frequency of the 500hPa anticyclones and a decrease of low pressures. However, some high altitude stations showed an intensification of precipitation events. This would exacerbate need for proper planning of future water resource management and farming strategies. Soil moisture rainfall feedback mechanisms were not fully explored. However drier conditions experiments showed a stronger response to soil moisture perturbations than in wetter conditions experiments. No consistent response to soil moisture initialisation over southern Africa was found. The altitude does modulate these feedback mechanisms with low-lying areas depicting a stronger response. A better understanding of the observed rainfall patterns, historical climate trends and soil moisture-rainfall feedback mechanisms are essential for improved short-term and seasonal forecasting and will aid the generation of plausible climate change impact predictions. DA - 2005 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2005 T1 - Climatic trends and soil moisture feedbacks over Zimbabwe TI - Climatic trends and soil moisture feedbacks over Zimbabwe UR - http://hdl.handle.net/11427/4783 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/4783
dc.identifier.vancouvercitationMdoka ML. Climatic trends and soil moisture feedbacks over Zimbabwe. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Environmental and Geographical Science, 2005 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/4783en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Environmental and Geographical Scienceen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherEnvironmental and Geographical Scienceen_ZA
dc.titleClimatic trends and soil moisture feedbacks over Zimbabween_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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