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Dr. Christina Botai
South African Weather Service

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0 Water Analysis
0 Drought
0 Flood Analysis
0 Water - Food - Energy Nexus
0 Hyrology

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Water - Food - Energy Nexus

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Review
Published: 21 June 2021 in Agronomy
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Funders and governments are promoting climate-smart agriculture (CSA) as key to agricultural adaptation under climate change in Africa. However, with its progressions still at the policy level and framework description, there is a need to understand the current developments and activities conducted within the CSA research field. We conducted a scientific mapping and analyses of CSA research studies in Africa to understand the (i) thematic trends, (ii) developments, (iii) nature of collaboration networks, and (iv) general narratives supporting the adoption and application of CSA in Africa. Results show that several African countries had endorsed CSA as an approach to addressing agricultural productivity challenges, supporting adaptation strategies, and building resilience to climate change. However, a majority do not have national Climate-Smart Agriculture Investment Plans (CSAIPs). Additionally, CSA research in Africa is still developing, with only a few countries dominating the research outputs. For a successful implementation of CSA, a framework provided by the CSAIPs must be established to guide the processes. This will provide a framework to guide the integration of government programs, policies, and strategic plans by combining other inputs from stakeholders to support decision making and implementation of CSA.

ACS Style

Paul Barasa; Christina Botai; Joel Botai; Tafadzwanashe Mabhaudhi. A Review of Climate-Smart Agriculture Research and Applications in Africa. Agronomy 2021, 11, 1255 .

AMA Style

Paul Barasa, Christina Botai, Joel Botai, Tafadzwanashe Mabhaudhi. A Review of Climate-Smart Agriculture Research and Applications in Africa. Agronomy. 2021; 11 (6):1255.

Chicago/Turabian Style

Paul Barasa; Christina Botai; Joel Botai; Tafadzwanashe Mabhaudhi. 2021. "A Review of Climate-Smart Agriculture Research and Applications in Africa." Agronomy 11, no. 6: 1255.

Journal article
Published: 10 May 2021 in Sustainability
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Heat stress-related illness attributed to the changing climate, particularly the more frequent extreme high temperatures, is becoming a theme of public concern, especially in the most vulnerable regions, such as the African continent. Knowledge of the existing research directions and gaps on heat stress and human health is vital for informing future strategic research foci capable of influencing policy development, planning, adaptation, and mitigation efforts. In this regard, a bibliometric analysis was conducted, with an emphasis on Africa, to assess regional research contributions to heat stress impacts on human health. The goals of the study were to review publication growth and patterns of the scientific publications and to identify key players (especially collaborating institutions and countries) and the evolution of research themes on the African continent, while paying attention to global trends and emergent hot topics and methodology of heat stress research. Using the Web of Science (WoS) and Scopus core collection databases, a structured keyword search was undertaken, which yielded 463 and 58 research publications from around the world and Africa, respectively. The retrieved scientific documents, published between 1968 and 2020, were analyzed and visualized using a bibliometric analysis technique and the VOSviewer software tool. The results indicate low statistics and slow scientific growth in publication output, with the highest peak having been reached in 2018, resulting in 13 scientific publications. While global research collaborations are successfully reflected in the literature, there is a considerable gap in understanding heat stress and related collaborations between African countries and international institutions. The review study has identified key opportunities that can benefit Africa through the expansion of the scope of heat stress and human health research on the continent. These opportunities can be achieved by closing the following research gaps: (1) vulnerability assessments within demographic classes, such as the elderly, (2) personal exposure and associated risks, (3) Urban Heat Island (UHI) evaluation for urban environments, and (4) heat adaptation research, which will enable informed and targeted preventive actions that will limit future heat health impacts. The authors opine that the pursuit of such studies will be most impactful if the current knowledge gaps are bridged through transdisciplinary research supported by local, regional, and international collaborators.

ACS Style

Katlego Ncongwane; Joel Botai; Venkataraman Sivakumar; Christina Botai. A Literature Review of the Impacts of Heat Stress on Human Health across Africa. Sustainability 2021, 13, 5312 .

AMA Style

Katlego Ncongwane, Joel Botai, Venkataraman Sivakumar, Christina Botai. A Literature Review of the Impacts of Heat Stress on Human Health across Africa. Sustainability. 2021; 13 (9):5312.

Chicago/Turabian Style

Katlego Ncongwane; Joel Botai; Venkataraman Sivakumar; Christina Botai. 2021. "A Literature Review of the Impacts of Heat Stress on Human Health across Africa." Sustainability 13, no. 9: 5312.

Review
Published: 06 February 2021 in Sustainability
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Notwithstanding the dispersed nature of the water, energy and food (WEF) nexus scholarship in the African continent, its strategic importance to the African agenda has gained widespread attention in research and planning circles. In this regard, the bibliometric science mapping and content analysis of the WEF nexus scientific publication trends, the conceptual, intellectual and social structures, as well as the inherent paradigmatic shifts in the WEF nexus body of knowledge in the African continent have been undertaken, using the nexus body of literature accessed from the Web of Science and Scopus core collection databases. The review results confirmed that, whilst the WEF nexus scholarship has expanded since 2013, there is also evidence of growth in the conceptual, intellectual and social structures of the WEF nexus in the African continent. These shifts have resulted in the emergence of hot topics (subfields) including modelling and optimization, climate variability and change, environmental ecosystem services sustainability, and sustainable development and livelihoods. The review further determined that these structures have evolved along two main perspectives of WEF nexus research development, i.e., the interdisciplinary and transdisciplinary domains. In support of the interpretation of the visual analytics of the intellectual structure and changing patterns of the WEF nexus research, the shifts in positivist, interpretivist and pragmatic paradigmatic perspectives (these are underpinned by the ontology, epistemology, and methodology and methods) are considered when explaining WEF nexus research shifts: (a) From the unconnected silo paradigms that focus on water, energy and food (security concerns) to interconnected (and sometimes interdependent or nested) linkages or systems incorporating environmental, social-economic and political drivers (also viewed as subfields) in a bid to holistically support the Sustainable Development Goals (SDGs) across the African continent; and (b) in the evaluation of the WEF nexus scholarship based on novel analytical approaches. We contend that whilst the theories of science change underpin this apparent expansion, the macro-economic theory will find use in explaining how the WEF nexus research agenda is negotiated and the Integrative Environmental Governance (IEG) is the duly suited governance theory to bridge the inherent disconnect between WEF nexus output and governance processes uncovered in the literature. Overall, operational challenges and opportunities of the WEF nexus abound, transitioning the WEF nexus research to practice in Africa, motivating the need to take advantage of the scholar–practitioner research underpinnings, as contemplated in the transdisciplinary research approach, which is characterised by the dual quest for new knowledge and considerations of use. Yet, there is need for more coordinated and collaborative research to achieve impact and transition from WEF nexus thinking to WEF nexus practice.

ACS Style

Joel Botai; Christina Botai; Katlego Ncongwane; Sylvester Mpandeli; Luxon Nhamo; Muthoni Masinde; Abiodun Adeola; Michael Mengistu; Henerica Tazvinga; Miriam Murambadoro; Shenelle Lottering; Isaac Motochi; Patrick Hayombe; Nosipho Zwane; Eric Wamiti; Tafadzwanashe Mabhaudhi. A Review of the Water–Energy–Food Nexus Research in Africa. Sustainability 2021, 13, 1762 .

AMA Style

Joel Botai, Christina Botai, Katlego Ncongwane, Sylvester Mpandeli, Luxon Nhamo, Muthoni Masinde, Abiodun Adeola, Michael Mengistu, Henerica Tazvinga, Miriam Murambadoro, Shenelle Lottering, Isaac Motochi, Patrick Hayombe, Nosipho Zwane, Eric Wamiti, Tafadzwanashe Mabhaudhi. A Review of the Water–Energy–Food Nexus Research in Africa. Sustainability. 2021; 13 (4):1762.

Chicago/Turabian Style

Joel Botai; Christina Botai; Katlego Ncongwane; Sylvester Mpandeli; Luxon Nhamo; Muthoni Masinde; Abiodun Adeola; Michael Mengistu; Henerica Tazvinga; Miriam Murambadoro; Shenelle Lottering; Isaac Motochi; Patrick Hayombe; Nosipho Zwane; Eric Wamiti; Tafadzwanashe Mabhaudhi. 2021. "A Review of the Water–Energy–Food Nexus Research in Africa." Sustainability 13, no. 4: 1762.

Journal article
Published: 24 November 2020 in Water
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This research study evaluated the projected future climate and anticipated impacts on water-linked sectors on the transboundary Limpopo River Basin (LRB) with a focus on South Africa. Streamflow was simulated from two CORDEX-Africa regional climate models (RCMs) forced by the 5th phase of the Coupled Model Inter-Comparison Project (CMIP5) Global Climate Models (GCMs), namely, the CanESM2m and IPSL-CM5A-MR climate models. Three climate projection time intervals were considered spanning from 2006 to 2099 and delineated as follows: current climatology (2006–2035), near future (2036–2065) and end of century future projection (2070–2099). Statistical metrics derived from the projected streamflow were used to assess the impacts of the changing climate on water-linked sectors. These metrics included streamflow trends, low and high flow quantile probabilities, the Standardized Streamflow Index (SSI) trends and the proportion (%) of dry and wet years, as well as drought monitoring indicators. Based on the Mann-Kendall (MK) trend test, the LRB is projected to experience reduced streamflow in both the near and the distant future. The basin is projected to experience frequent dry and wet conditions that can translate to drought and flash floods, respectively. In particular, a high proportion of dry and a few incidences of wet years are expected in the basin in the future. In general, the findings of this research study will inform and enhance climate change adaptation and mitigation policy decisions and implementation thereof, to sustain the livelihoods of vulnerable communities.

ACS Style

Christina M. Botai; Joel O. Botai; Nosipho N. Zwane; Patrick Hayombe; Eric K. Wamiti; Thabo Makgoale; Miriam D. Murambadoro; Abiodun M. Adeola; Katlego P. Ncongwane; Jaco P. De Wit; Michael G. Mengistu; Henerica Tazvinga. Hydroclimatic Extremes in the Limpopo River Basin, South Africa, under Changing Climate. Water 2020, 12, 3299 .

AMA Style

Christina M. Botai, Joel O. Botai, Nosipho N. Zwane, Patrick Hayombe, Eric K. Wamiti, Thabo Makgoale, Miriam D. Murambadoro, Abiodun M. Adeola, Katlego P. Ncongwane, Jaco P. De Wit, Michael G. Mengistu, Henerica Tazvinga. Hydroclimatic Extremes in the Limpopo River Basin, South Africa, under Changing Climate. Water. 2020; 12 (12):3299.

Chicago/Turabian Style

Christina M. Botai; Joel O. Botai; Nosipho N. Zwane; Patrick Hayombe; Eric K. Wamiti; Thabo Makgoale; Miriam D. Murambadoro; Abiodun M. Adeola; Katlego P. Ncongwane; Jaco P. De Wit; Michael G. Mengistu; Henerica Tazvinga. 2020. "Hydroclimatic Extremes in the Limpopo River Basin, South Africa, under Changing Climate." Water 12, no. 12: 3299.

Review
Published: 12 August 2020 in Sustainability
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The African continent has a long history of rainfall fluctuations of varying duration and intensities. This has led to varying degrees of drought conditions, triggering research interest across the continent. The research presented here is a bibliometric analysis of scientific articles on drought monitoring and prediction published in Africa. Scientific data analysis was carried out based on bibliometric mapping techniques applied to 332 scientific publications (1980 to 2020) retrieved from the Web of Science (WoS) and Scopus databases. In addition, time series of Standardized Precipitation Evapotranspiration Index for the previous 6 months (SPEI-6) over six regions in the continent was analysed giving the relative comparison of drought occurrences to the annual distribution of the scientific publications. The results revealed that agricultural and hydrological drought studies contributed about 75% of the total publications, while the remaining 25% was shared among socioeconomic and meteorological studies. Countries in the southern, western, and eastern regions of Africa led in terms of scientific publications during the period under review. The results further indicated that the continent experienced drought conditions in the years 1984, 1989, 1992, and 1997, thereby inducing an increase in the number of scientific publications on drought studies. The results show that the tools of analysis have also changed from simple statistics to the use of geospatial tools such as Remote Sensing (RS) and Geographical Information System (GIS) models, and recently Machine Learning (ML). The ML, particularly, contributed about 11% of the total scientific publications, while RS and GIS models, and basic statistical analysis account for about 44%, 20%, and 25% respectively. The integration of spatial technologies and ML are pivotal to the development of robust drought monitoring and drought prediction systems, especially in Africa, which is considered as a drought-prone continent. The research gaps presented in this study can help prospective researchers to respond to the continental and regional drought research needs.

ACS Style

Omolola Adisa; Muthoni Masinde; Joel Botai; Christina Botai. Bibliometric Analysis of Methods and Tools for Drought Monitoring and Prediction in Africa. Sustainability 2020, 12, 6516 .

AMA Style

Omolola Adisa, Muthoni Masinde, Joel Botai, Christina Botai. Bibliometric Analysis of Methods and Tools for Drought Monitoring and Prediction in Africa. Sustainability. 2020; 12 (16):6516.

Chicago/Turabian Style

Omolola Adisa; Muthoni Masinde; Joel Botai; Christina Botai. 2020. "Bibliometric Analysis of Methods and Tools for Drought Monitoring and Prediction in Africa." Sustainability 12, no. 16: 6516.

Journal article
Published: 08 July 2020 in Water
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This research study was carried out to investigate the characteristics of drought based on the joint distribution of two dependent variables, the duration and severity, in the Eastern Cape Province, South Africa. The drought variables were computed from the Standardized Precipitation Index for 6- and 12-month accumulation period (hereafter SPI-6 and SPI-12) time series calculated from the monthly rainfall data spanning the last five decades. In this context, the characteristics of climatological drought duration and severity were based on multivariate copula analysis. Five copula functions (from the Archimedean and Elliptical families) were selected and fitted to the drought duration and severity series in order to assess the dependency measure of the two variables. In addition, Joe and Gaussian copula functions were considered and fitted to the drought duration and severity to assess the joint return periods for the dual and cooperative cases. The results indicate that the dependency measure of drought duration and severity are best described by Tawn copula families. The dependence structure results suggest that the study area exhibited low probability of drought duration and high probability of drought severity. Furthermore, the multivariate return period for the dual case is found to be always longer across all the selected univariate return periods. Based on multivariate analysis, the study area (particularly Buffalo City, OR Tambo and Alfred Zoo regions) is determined to have higher/lower risks in terms of the conjunctive/cooperative multivariate drought risk (copula) probability index. The results of the present study could contribute towards policy and decision making through e.g., formulation of the forward-looking contingent plans for sustainable management of water resources and the consequent applications in the preparedness for and adaptation to the drought risks in the water-linked sectors of the economy.

ACS Style

Christina M. Botai; Joel O. Botai; Abiodun M. Adeola; Jaco P. De Wit; Katlego P. Ncongwane; Nosipho N. Zwane. Drought Risk Analysis in the Eastern Cape Province of South Africa: The Copula Lens. Water 2020, 12, 1938 .

AMA Style

Christina M. Botai, Joel O. Botai, Abiodun M. Adeola, Jaco P. De Wit, Katlego P. Ncongwane, Nosipho N. Zwane. Drought Risk Analysis in the Eastern Cape Province of South Africa: The Copula Lens. Water. 2020; 12 (7):1938.

Chicago/Turabian Style

Christina M. Botai; Joel O. Botai; Abiodun M. Adeola; Jaco P. De Wit; Katlego P. Ncongwane; Nosipho N. Zwane. 2020. "Drought Risk Analysis in the Eastern Cape Province of South Africa: The Copula Lens." Water 12, no. 7: 1938.

Journal article
Published: 17 December 2019 in International Journal of Environmental Research and Public Health
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This contribution aims to investigate the influence of monthly total rainfall variations on malaria transmission in the Limpopo Province. For this purpose, monthly total rainfall was interpolated from daily rainfall data from weather stations. Annual and seasonal trends, as well as cross-correlation analyses, were performed on time series of monthly total rainfall and monthly malaria cases in five districts of Limpopo Province for the period of 1998 to 2017. The time series analysis indicated that an average of 629.5 mm of rainfall was received over the period of study. The rainfall has an annual variation of about 0.46%. Rainfall amount varied within the five districts, with the northeastern part receiving more rainfall. Spearman’s correlation analysis indicated that the total monthly rainfall with one to two months lagged effect is significant in malaria transmission across all the districts. The strongest correlation was noticed in Vhembe (r = 0.54; p-value =

ACS Style

Abiodun Adeola; Katlego Ncongwane; Gbenga Abiodun; Thabo Makgoale; Hannes Rautenbach; Joel Botai; Omolola Adisa; Christina Botai. Rainfall Trends and Malaria Occurrences in Limpopo Province, South Africa. International Journal of Environmental Research and Public Health 2019, 16, 5156 .

AMA Style

Abiodun Adeola, Katlego Ncongwane, Gbenga Abiodun, Thabo Makgoale, Hannes Rautenbach, Joel Botai, Omolola Adisa, Christina Botai. Rainfall Trends and Malaria Occurrences in Limpopo Province, South Africa. International Journal of Environmental Research and Public Health. 2019; 16 (24):5156.

Chicago/Turabian Style

Abiodun Adeola; Katlego Ncongwane; Gbenga Abiodun; Thabo Makgoale; Hannes Rautenbach; Joel Botai; Omolola Adisa; Christina Botai. 2019. "Rainfall Trends and Malaria Occurrences in Limpopo Province, South Africa." International Journal of Environmental Research and Public Health 16, no. 24: 5156.

Journal article
Published: 21 February 2019 in Sustainability
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The use of crop modeling as a decision tool by farmers and other decision-makers in the agricultural sector to improve production efficiency has been on the increase. In this study, artificial neural network (ANN) models were used for predicting maize in the major maize producing provinces of South Africa. The maize production prediction and projection analysis were carried out using the following climate variables: precipitation (PRE), maximum temperature (TMX), minimum temperature (TMN), potential evapotranspiration (PET), soil moisture (SM) and land cultivated (Land) for maize. The analyzed datasets spanned from 1990 to 2017 and were divided into two segments with 80% used for model training and the remaining 20% for testing. The results indicated that PET, PRE, TMN, TMX, Land, and SM with two hidden neurons of vector (5,8) were the best combination to predict maize production in the Free State province, whereas the TMN, TMX, PET, PRE, SM and Land with vector (7,8) were the best combination for predicting maize in KwaZulu-Natal province. In addition, the TMN, SM and Land and TMN, TMX, SM and Land with vector (3,4) were the best combination for maize predicting in the North West and Mpumalanga provinces, respectively. The comparison between the actual and predicted maize production using the testing data indicated performance accuracy adjusted R2 of 0.75 for Free State, 0.67 for North West, 0.86 for Mpumalanga and 0.82 for KwaZulu-Natal. Furthermore, a decline in the projected maize production was observed across all the selected provinces (except the Free State province) from 2018 to 2019. Thus, the developed model can help to enhance the decision making process of the farmers and policymakers.

ACS Style

Omolola M. Adisa; Joel O. Botai; Abiodun M. Adeola; Abubeker Hassen; Christina M. Botai; Daniel Darkey; Eyob Tesfamariam. Application of Artificial Neural Network for Predicting Maize Production in South Africa. Sustainability 2019, 11, 1145 .

AMA Style

Omolola M. Adisa, Joel O. Botai, Abiodun M. Adeola, Abubeker Hassen, Christina M. Botai, Daniel Darkey, Eyob Tesfamariam. Application of Artificial Neural Network for Predicting Maize Production in South Africa. Sustainability. 2019; 11 (4):1145.

Chicago/Turabian Style

Omolola M. Adisa; Joel O. Botai; Abiodun M. Adeola; Abubeker Hassen; Christina M. Botai; Daniel Darkey; Eyob Tesfamariam. 2019. "Application of Artificial Neural Network for Predicting Maize Production in South Africa." Sustainability 11, no. 4: 1145.

Journal article
Published: 11 February 2019 in Water
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The spatial-temporal variability of drought characteristics and propagation mechanisms in the hydrological cycle is a pertinent topic to policymakers and to the diverse scientific community. This study reports on the analysis of drought characteristics and propagation patterns in the hydrological cycle over South Africa. In particular, the analysis considered daily precipitation and streamflow data spanning from 1985 to 2016, recorded from 74 weather stations, distributed across South Africa and covering the country’s 19 Water Management Areas (WMAs). The results show that all the WMAs experience drought features characterized by an inherent spatial-temporal dependence structure with transition periods categorized into short (1–3 months), intermediate (4–6 months), long (7–12 months) and extended (>12 months) time-scales. Coupled with climate and catchment characteristics, the drought propagation characteristics delineate the WMAs into homogenous zones subtly akin to the broader climatic zones of South Africa, i.e., Savanna, Grassland, Karoo, Fynbos, Forest, and Desert climates. We posit that drought evolution results emanating from the current study provide a new perspective of drought characterization with practical use for the design of drought monitoring, as well as early warning systems for drought hazard preparedness and effective water resources planning and management. Overall, the analysis of drought evolution in South Africa is expected to stimulate advanced drought research topics, including the elusive drought termination typology.

ACS Style

Joel Ondego Botai; Christina M. Botai; Jaco P. De Wit; Masinde Muthoni; Abiodun M. Adeola. Analysis of Drought Progression Physiognomies in South Africa. Water 2019, 11, 299 .

AMA Style

Joel Ondego Botai, Christina M. Botai, Jaco P. De Wit, Masinde Muthoni, Abiodun M. Adeola. Analysis of Drought Progression Physiognomies in South Africa. Water. 2019; 11 (2):299.

Chicago/Turabian Style

Joel Ondego Botai; Christina M. Botai; Jaco P. De Wit; Masinde Muthoni; Abiodun M. Adeola. 2019. "Analysis of Drought Progression Physiognomies in South Africa." Water 11, no. 2: 299.

Journal article
Published: 27 August 2018 in Sustainability
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Changes in phenology can be used as a proxy to elucidate the short and long term trends in climate change and variability. Such phenological changes are driven by weather and climate as well as environmental and ecological factors. Climate change affects plant phenology largely during the vegetative and reproductive stages. The focus of this study was to investigate the changes in phenological parameters of maize as well as to assess their causal factors across the selected maize-producing Provinces (viz: North West, Free State, Mpumalanga and KwaZulu-Natal) of South Africa. For this purpose, five phenological parameters i.e., the length of season (LOS), start of season (SOS), end of season (EOS), position of peak value (POP), and position of trough value (POT) derived from the MODIS NDVI data (MOD13Q1) were analysed. In addition, climatic variables (Potential Evapotranspiration (PET), Precipitation (PRE), Maximum (TMX) and Minimum (TMN) Temperatures spanning from 2000 to 2015 were also analysed. Based on the results, the maize-producing Provinces considered exhibit a decreasing trend in NDVI values. The results further show that Mpumalanga and Free State Provinces have SOS and EOS in December and April respectively. In terms of the LOS, KwaZulu-Natal Province had the highest days (194), followed by Mpumalanga with 177 days, while North West and Free State Provinces had 149 and 148 days, respectively. Our results further demonstrate that the influences of climate variables on phenological parameters exhibit a strong space-time and common covariate dependence. For instance, TMN dominated in North West and Free State, PET and TMX are the main dominant factors in KwaZulu-Natal Province whereas PRE highly dominated in Mpumalanga. Furthermore, the result of the Partial Least Square Path Modeling (PLS-PM) analysis indicates that climatic variables predict about 46% of the variability of phenology indicators and about 63% of the variability of yield indicators for the entire study area. The goodness of fit index indicates that the model has a prediction power of 75% over the entire study area. This study contributes towards enhancing the knowledge of the dynamics in the phenological parameters and the results can assist farmers to make the necessary adjustment in order to have an optimal production and thereby enhance food security for both human and livestock.

ACS Style

Omolola M. Adisa; Joel Botai; Abubeker Hassen; Daniel Darkey; Abiodun M. Adeola; Eyob Tesfamariam; Christina M. Botai; Abidemi T. Adisa. Variability of Satellite Derived Phenological Parameters across Maize Producing Areas of South Africa. Sustainability 2018, 10, 3033 .

AMA Style

Omolola M. Adisa, Joel Botai, Abubeker Hassen, Daniel Darkey, Abiodun M. Adeola, Eyob Tesfamariam, Christina M. Botai, Abidemi T. Adisa. Variability of Satellite Derived Phenological Parameters across Maize Producing Areas of South Africa. Sustainability. 2018; 10 (9):3033.

Chicago/Turabian Style

Omolola M. Adisa; Joel Botai; Abubeker Hassen; Daniel Darkey; Abiodun M. Adeola; Eyob Tesfamariam; Christina M. Botai; Abidemi T. Adisa. 2018. "Variability of Satellite Derived Phenological Parameters across Maize Producing Areas of South Africa." Sustainability 10, no. 9: 3033.

Original paper
Published: 18 November 2017 in Theoretical and Applied Climatology
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This study analyzed the variability of the agro-climatic parameters that impact maize production across different seasons in South Africa. To achieve this, four agro-climatic variables (precipitation, potential evapotranspiration, minimum, and maximum temperatures) were considered for the period spanning 1986–2015, covering the North West, Free State, Mpumalanga, and KwaZulu-Natal (KZN) provinces. Results illustrate that there is a negative trend in precipitation for North West and Free State provinces and positive trend in maximum temperature for all the provinces over the study period. Furthermore, the results showed that among other agro-climatic parameters, minimum temperature had the most influence on maize production in North West, potential evapotranspiration (combination of the agro-climatic parameters), minimum and maximum temperature influenced maize production in KZN while maximum temperature influenced maize production in Mpumalanga and Free State. In general, the agro-climatic parameters were found to contribute 7.79, 21.85, 32.52, and 44.39% to variation in maize production during the study period in North West, Free State, Mpumalanga, and KZN, respectively. The variation in maize production among the provinces under investigation could most likely attribute to the variation in the size of the cultivated land among other factors including soil type and land tenure system. There were also difference in yield per hectare between the provinces; KZN and Mpumalanga being located in the humid subtropical areas of South Africa had the highest yield per hectare 5.61 and 4.99 tons, respectively, while Free State and North West which are in the semi-arid region had the lowest yield per hectare 3.86 and 3.03 tons, respectively. Understanding the nature and interaction of the dominant agro-climatic parameters discussed in the present study as well as their impact on maize production will help farmers and agricultural policy makers to understand how climate change exerts its influence on maize production within the study area so as to better adapt to the major climate element that either increases or decreases maize production in their respective provinces.

ACS Style

Omolola Adisa; Christina M. Botai; Joel Botai; Abubeker Hassen; Daniel Darkey; Eyob Tesfamariam; Alex F. Adisa; Abiodun M. Adeola; Katlego P. Ncongwane. Analysis of agro-climatic parameters and their influence on maize production in South Africa. Theoretical and Applied Climatology 2017, 134, 991 -1004.

AMA Style

Omolola Adisa, Christina M. Botai, Joel Botai, Abubeker Hassen, Daniel Darkey, Eyob Tesfamariam, Alex F. Adisa, Abiodun M. Adeola, Katlego P. Ncongwane. Analysis of agro-climatic parameters and their influence on maize production in South Africa. Theoretical and Applied Climatology. 2017; 134 (3-4):991-1004.

Chicago/Turabian Style

Omolola Adisa; Christina M. Botai; Joel Botai; Abubeker Hassen; Daniel Darkey; Eyob Tesfamariam; Alex F. Adisa; Abiodun M. Adeola; Katlego P. Ncongwane. 2017. "Analysis of agro-climatic parameters and their influence on maize production in South Africa." Theoretical and Applied Climatology 134, no. 3-4: 991-1004.

Journal article
Published: 10 November 2017 in Water
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Drought is a creeping phenomenon whose effects evolve with time, yet the start and end is often only clear in the hindsight. The present study assessed drought conditions using two categories of drought indicators computed from precipitation data sets measured by weather stations across the Western Cape Province, South Africa for the period 1985 to 2016. The first category was the Standardized Precipitation Index (SPI) accumulated over 3-, 6- and 12-months (hereafter of SPI-3, SPI-6 and SPI-12 respectively). The second category consists of the four Drought Monitoring Indicators (DMI) i.e., Drought Duration (DD), Severity (DS), Intensity (DI) and Frequency (DF). Firstly, analysis of SPI-3, SPI-6 and SPI-12 illustrate that between 1985 and 2016, the Western Cape Province experienced recurrent mild drought conditions. This suggests that the drought conditions experienced during 2015/2016 hydrological year (hereafter current) in the Western Cape Province is a manifestation of past drought conditions. Secondly, analysis of trends in DMI series depict a noticeable spatial-temporal dependence wherein the southern and western regions experienced more severe droughts compared to the eastern and northern regions of the Western Cape Province. Results also show that the DMI trends exhibit up to ~8% variability over the past decade. Overall, the current drought conditions in the Western Cape Province continues to adversely affect agricultural production while the water reservoirs are at below 30% capacity implying that the socio-economic impacts of these droughts will continue to reverberate for many months to come. Though the on-going drought conditions in the Western Cape Province is a regular part of nature’s cycle, analysis of historical drought characteristics based on drought indicators is an important first step towards placing the current drought conditions into perspective, and contribute to triggering action and response thereof. All these lay the foundation for drought monitoring and contribute towards the development of drought early warning.

ACS Style

Christina M. Botai; Joel O. Botai; Jaco P. De Wit; Katlego P. Ncongwane; Abiodun M. Adeola. Drought Characteristics over the Western Cape Province, South Africa. Water 2017, 9, 876 .

AMA Style

Christina M. Botai, Joel O. Botai, Jaco P. De Wit, Katlego P. Ncongwane, Abiodun M. Adeola. Drought Characteristics over the Western Cape Province, South Africa. Water. 2017; 9 (11):876.

Chicago/Turabian Style

Christina M. Botai; Joel O. Botai; Jaco P. De Wit; Katlego P. Ncongwane; Abiodun M. Adeola. 2017. "Drought Characteristics over the Western Cape Province, South Africa." Water 9, no. 11: 876.

Journal article
Published: 08 November 2017 in International Journal of Environmental Research and Public Health
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The north-eastern parts of South Africa, comprising the Limpopo Province, have recorded a sudden rise in the rate of malaria morbidity and mortality in the 2017 malaria season. The epidemiological profiles of malaria, as well as other vector-borne diseases, are strongly associated with climate and environmental conditions. A retrospective understanding of the relationship between climate and the occurrence of malaria may provide insight into the dynamics of the disease’s transmission and its persistence in the north-eastern region. In this paper, the association between climatic variables and the occurrence of malaria was studied in the Mutale local municipality in South Africa over a period of 19-year. Time series analysis was conducted on monthly climatic variables and monthly malaria cases in the Mutale municipality for the period of 1998–2017. Spearman correlation analysis was performed and the Seasonal Autoregressive Integrated Moving Average (SARIMA) model was developed. Microsoft Excel was used for data cleaning, and statistical software R was used to analyse the data and develop the model. Results show that both climatic variables’ and malaria cases’ time series exhibited seasonal patterns, showing a number of peaks and fluctuations. Spearman correlation analysis indicated that monthly total rainfall, mean minimum temperature, mean maximum temperature, mean average temperature, and mean relative humidity were significantly and positively correlated with monthly malaria cases in the study area. Regression analysis showed that monthly total rainfall and monthly mean minimum temperature (R2 = 0.65), at a two-month lagged effect, are the most significant climatic predictors of malaria transmission in Mutale local municipality. A SARIMA (2,1,2) (1,1,1) model fitted with only malaria cases has a prediction performance of about 51%, and the SARIMAX (2,1,2) (1,1,1) model with climatic variables as exogenous factors has a prediction performance of about 72% in malaria cases. The model gives a close comparison between the predicted and observed number of malaria cases, hence indicating that the model provides an acceptable fit to predict the number of malaria cases in the municipality. To sum up, the association between the climatic variables and malaria cases provides clues to better understand the dynamics of malaria transmission. The lagged effect detected in this study can help in adequate planning for malaria intervention.

ACS Style

Abiodun M. Adeola; Joel O. Botai; Hannes Rautenbach; Omolola M. Adisa; Katlego P. Ncongwane; Christina M. Botai; Temitope C. Adebayo-Ojo. Climatic Variables and Malaria Morbidity in Mutale Local Municipality, South Africa: A 19-Year Data Analysis. International Journal of Environmental Research and Public Health 2017, 14, 1360 .

AMA Style

Abiodun M. Adeola, Joel O. Botai, Hannes Rautenbach, Omolola M. Adisa, Katlego P. Ncongwane, Christina M. Botai, Temitope C. Adebayo-Ojo. Climatic Variables and Malaria Morbidity in Mutale Local Municipality, South Africa: A 19-Year Data Analysis. International Journal of Environmental Research and Public Health. 2017; 14 (11):1360.

Chicago/Turabian Style

Abiodun M. Adeola; Joel O. Botai; Hannes Rautenbach; Omolola M. Adisa; Katlego P. Ncongwane; Christina M. Botai; Temitope C. Adebayo-Ojo. 2017. "Climatic Variables and Malaria Morbidity in Mutale Local Municipality, South Africa: A 19-Year Data Analysis." International Journal of Environmental Research and Public Health 14, no. 11: 1360.

Journal article
Published: 10 October 2016 in Water
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The Free State (FS) and North West (NW) Provinces are often hard hit by droughts with impacts on water availability, farm production and livestock holdings. The South African government declared the two Provinces drought disaster areas in the 2015/2016 hydrological year. This is a major drawback, since both the Provinces play an important role to South African economy as they are a haven to agricultural production and have major water reservoirs in South Africa. This study was undertaken to investigate the historical evolution of drought within the FS and NW Provinces over the past 30 years. The Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) calculated based on monthly meteorological data from 14 weather/climate stations within the FS and NW Provinces were used to explore and characterize variation in drought intensity, duration, frequency and severity in FS and NW Provinces during 1985–2015. Results indicate that there exist localized positive and negative trends with spatial dependence across the selected stations. In particular, about 60% of the weather stations exhibiting a decreasing trend are located in FS Province, suggesting that FS has being experiencing increasing drought during the analyzed period compared to NW Province. Results from the analysis of drought evaluation indicators (DEIs) calculated from SPEI suggest that drought severity and frequency was more pronounced in FS while the intensity of the drought was more in NW Province during 1985–2015. In addition, based on SPEI calculations, moderate drought occurrences increased during 1985–1994 and 1995–2004 periods and decreased thereafter (2005–2015) in both Provinces. Drought classification based on parameters derived from SPEI produced similar results for mild drought occurrences during the same time scales.

ACS Style

Christina M. Botai; Joel O. Botai; Lucky C. Dlamini; Nosipho S. Zwane; Elelwani Phaduli. Characteristics of Droughts in South Africa: A Case Study of Free State and North West Provinces. Water 2016, 8, 439 .

AMA Style

Christina M. Botai, Joel O. Botai, Lucky C. Dlamini, Nosipho S. Zwane, Elelwani Phaduli. Characteristics of Droughts in South Africa: A Case Study of Free State and North West Provinces. Water. 2016; 8 (10):439.

Chicago/Turabian Style

Christina M. Botai; Joel O. Botai; Lucky C. Dlamini; Nosipho S. Zwane; Elelwani Phaduli. 2016. "Characteristics of Droughts in South Africa: A Case Study of Free State and North West Provinces." Water 8, no. 10: 439.

Review
Published: 15 April 2015 in Water
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Water resources, particularly in arid and semi-arid regions of the world are of great concern, as they are closely linked to the wellbeing of humankind. Sophisticated hydrological prediction tools are required to assess climatic and hydrometeorological conditions, as they impact the sustainability of water resources as well as water availability. Research and data collection activities from multi-hydrometeorological sensors (e.g., gauges, radars, satellites) form the basis for quantifying the impact of extreme episodes along the hydrologic phases that manifest in terms of the magnitude, duration and frequency of floods, droughts and other hydrometeorological hazards that affect water resources management. A number of hydrometeorological research activities have been reported in the literature by various researchers and research groups globally. This contribution presents (a) a review of the hydrometeorology resource landscape in South Africa; (b) an analysis of the hydrometeorology services and products in South Africa; (c) a review of the hydrometeorological research that has been conducted in South Africa for the last four decades; and (d) highlights on some of the challenges facing the sustained advancement of research in hydrometeorology in South Africa.

ACS Style

Christina M. Botai; Joel O. Botai; Shepherd Muchuru; Isaac Ngwana. Hydrometeorological Research in South Africa: A Review. Water 2015, 7, 1580 -1594.

AMA Style

Christina M. Botai, Joel O. Botai, Shepherd Muchuru, Isaac Ngwana. Hydrometeorological Research in South Africa: A Review. Water. 2015; 7 (12):1580-1594.

Chicago/Turabian Style

Christina M. Botai; Joel O. Botai; Shepherd Muchuru; Isaac Ngwana. 2015. "Hydrometeorological Research in South Africa: A Review." Water 7, no. 12: 1580-1594.

Journal article
Published: 01 January 2015 in South African Journal of Science
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ACS Style

Christina M. Botai; Joel O. Botai; Ludwig Combrinck. Satellite laser ranging measurements in South Africa: Contributions to earth system sciences. South African Journal of Science 2015, 111, 1 -9.

AMA Style

Christina M. Botai, Joel O. Botai, Ludwig Combrinck. Satellite laser ranging measurements in South Africa: Contributions to earth system sciences. South African Journal of Science. 2015; 111 (3):1-9.

Chicago/Turabian Style

Christina M. Botai; Joel O. Botai; Ludwig Combrinck. 2015. "Satellite laser ranging measurements in South Africa: Contributions to earth system sciences." South African Journal of Science 111, no. 3: 1-9.