{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/12830"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/12830","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Rainfall variability over southern Africa","abstract":"Southern Africa is subject to high inter annual rainfall variability and the factors influencing southern African rainfall are not fully understood. The variability has been linked with various sea surface temperature anomalies (SSTAs) in each of the three major ocean basins as well as variability in the strength and position of regional atmospheric features. One of the atmospheric factors that may play a substantial role in southern African rainfall variability is the Botswana high, a high pressure cell which exists at the 500hPa level and is centred over central Namibia and western Botswana during austral summer. 20th Century reanalysis data is used to further investigate this feature and analysis reveals an association between the strength of the Botswana high and ENSO. Further analysis indicates that a connection between the Botswana high and rainfall over southern Africa not only exists during ENSO years, but is also apparent during neutral years that display ENSO-like characteristics in the Botswana high. This result may assist in producing better rainfall forecasts for non-ENSO years. The frequency of dry days over southern Africa during austral summer is investigated using GPCP observational data. Correlation analysis is generally in agreement with previous studies and showed that dry day frequency(DDF) over the Limpopo and North East Zambia regions is correlated with ENSO, while DDF over coastal northern Angola and central South Africa is correlated with SSTs in the Indian and Atlantic Oceans. The possible role played by DDF during JFM 1998 and JFM 2010 is investigated and results indicate that the distribution of DDF over southern Africa was notably different during these two seasons and may have contributed to the unexpected rainfall experienced over southern Africa.","abstract_html":"Southern Africa is subject to high inter annual rainfall variability and the factors influencing southern African rainfall are not fully understood. The variability has been linked with various sea surface temperature anomalies (SSTAs) in each of the three major ocean basins as well as variability in the strength and position of regional atmospheric features. One of the atmospheric factors that may play a substantial role in southern African rainfall variability is the Botswana high, a high pressure cell which exists at the 500hPa level and is centred over central Namibia and western Botswana during austral summer. 20th Century reanalysis data is used to further investigate this feature and analysis reveals an association between the strength of the Botswana high and ENSO. Further analysis indicates that a connection between the Botswana high and rainfall over southern Africa not only exists during ENSO years, but is also apparent during neutral years that display ENSO-like characteristics in the Botswana high. This result may assist in producing better rainfall forecasts for non-ENSO years. The frequency of dry days over southern Africa during austral summer is investigated using GPCP observational data. Correlation analysis is generally in agreement with previous studies and showed that dry day frequency(DDF) over the Limpopo and North East Zambia regions is correlated with ENSO, while DDF over coastal northern Angola and central South Africa is correlated with SSTs in the Indian and Atlantic Oceans. The possible role played by DDF during JFM 1998 and JFM 2010 is investigated and results indicate that the distribution of DDF over southern Africa was notably different during these two seasons and may have contributed to the unexpected rainfall experienced over southern Africa.","abstract_has_math":false,"creators":["Driver, Penny Meredith"],"institution":"Department of Oceanography","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Reason, Chris","Abiodun, Babatunde Joseph"],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014","date_published":"2014","updated_at":"2026-07-22T22:23:36Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/12830","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Reason, Chris","Abiodun, Babatunde Joseph"]},{"key":"dc:creator","label":"Author","values":["Driver, Penny Meredith"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-05-18T14:25:45Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-05-18T14:25:45Z"]},{"key":"dc:date.issued","label":"Date","values":["2014"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Oceanography"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/12830"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliographical references."]},{"key":"dc:description.abstract","label":"Abstract","values":["Southern Africa is subject to high inter annual rainfall variability and the factors influencing southern African rainfall are not fully understood. The variability has been linked with various sea surface temperature anomalies (SSTAs) in each of the three major ocean basins as well as variability in the strength and position of regional atmospheric features. One of the atmospheric factors that may play a substantial role in southern African rainfall variability is the Botswana high, a high pressure cell which exists at the 500hPa level and is centred over central Namibia and western Botswana during austral summer. 20th Century reanalysis data is used to further investigate this feature and analysis reveals an association between the strength of the Botswana high and ENSO. Further analysis indicates that a connection between the Botswana high and rainfall over southern Africa not only exists during ENSO years, but is also apparent during neutral years that display ENSO-like characteristics in the Botswana high. This result may assist in producing better rainfall forecasts for non-ENSO years. The frequency of dry days over southern Africa during austral summer is investigated using GPCP observational data. Correlation analysis is generally in agreement with previous studies and showed that dry day frequency(DDF) over the Limpopo and North East Zambia regions is correlated with ENSO, while DDF over coastal northern Angola and central South Africa is correlated with SSTs in the Indian and Atlantic Oceans. The possible role played by DDF during JFM 1998 and JFM 2010 is investigated and results indicate that the distribution of DDF over southern Africa was notably different during these two seasons and may have contributed to the unexpected rainfall experienced over southern Africa."]},{"key":"dc:title","label":"Title","values":["Rainfall variability over southern Africa"]}]}],"canonical_facts":{"dc:contributor.advisor":["Reason, Chris","Abiodun, Babatunde Joseph"],"dc:creator":["Driver, Penny Meredith"],"dc:date.accessioned":["2015-05-18T14:25:45Z"],"dc:date.available":["2015-05-18T14:25:45Z"],"dc:date.issued":["2014"],"dc:description":["Includes bibliographical references."],"dc:description.abstract":["Southern Africa is subject to high inter annual rainfall variability and the factors influencing southern African rainfall are not fully understood. The variability has been linked with various sea surface temperature anomalies (SSTAs) in each of the three major ocean basins as well as variability in the strength and position of regional atmospheric features. One of the atmospheric factors that may play a substantial role in southern African rainfall variability is the Botswana high, a high pressure cell which exists at the 500hPa level and is centred over central Namibia and western Botswana during austral summer. 20th Century reanalysis data is used to further investigate this feature and analysis reveals an association between the strength of the Botswana high and ENSO. Further analysis indicates that a connection between the Botswana high and rainfall over southern Africa not only exists during ENSO years, but is also apparent during neutral years that display ENSO-like characteristics in the Botswana high. This result may assist in producing better rainfall forecasts for non-ENSO years. The frequency of dry days over southern Africa during austral summer is investigated using GPCP observational data. Correlation analysis is generally in agreement with previous studies and showed that dry day frequency(DDF) over the Limpopo and North East Zambia regions is correlated with ENSO, while DDF over coastal northern Angola and central South Africa is correlated with SSTs in the Indian and Atlantic Oceans. The possible role played by DDF during JFM 1998 and JFM 2010 is investigated and results indicate that the distribution of DDF over southern Africa was notably different during these two seasons and may have contributed to the unexpected rainfall experienced over southern Africa."],"dc:identifier.uri":["http://hdl.handle.net/11427/12830"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Oceanography"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["Rainfall variability over southern Africa"],"dc:type":["Doctoral Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-22T22:23:36Z"}