Globally, lightning causes significant injury, death, and damage to infrastructure annually. In comparison to the rest of the world, South Africa has one of the highest incidences of lightning-related injuries and deaths. The latest... more
Globally, lightning causes significant injury, death, and damage to infrastructure annually. In comparison to the rest of the world, South Africa has one of the highest incidences of lightning-related injuries and deaths. The latest available lightning detection techniques and technologies are reviewed and include current research in South Africa and South Africa’s lightning detection challenges. Technological advances have contributed towards improving lightning detection and monitoring activities in many countries. South Africa has made considerably more progress in the field of lightning research than other African countries and possesses one of the three ground-based lightning detection networks in the southern hemisphere. However, despite these developments, rural communities in South Africa, and indeed in Africa, remain vulnerable to lightning, the occurrence of which is predicted to increase with climate change. A large proportion of the population of African countries reside...
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Central Africa is a global lightning hot spot, with the tropical areas including the top 10 highest lightning-flash-rate densities in the world. There are no lightning-locating-system networks available across most of Africa, however, and... more
Central Africa is a global lightning hot spot, with the tropical areas including the top 10 highest lightning-flash-rate densities in the world. There are no lightning-locating-system networks available across most of Africa, however, and it becomes necessary to make use of real-time, ground-based lightning early warning systems. Such a system was established in the southern Congo basin at the Kinsevere copper mine and has been operational since early 2015. The early warning system includes an electrical-field meter and a lightning-flash sensor, which produce two states of warning. Two years of data (July 2015–June 2016 and July 2016–July 2017) indicated a clear annual and daily peak in lightning activity, with an average lightning warning duration of 1.18 h and a maximum storm duration of 8.60 h. The seasonal flash occurrence was reasonably constant over the two years but was variable at a monthly level during the lightning season. Analysis of alarm state showed that the majority o...
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ABSTRACT Eucalyptus smithii is an important commercial forestry species in South Africa. The species’ shy and erratic flowering tendencies hinder its genetic improvement and seed production. Breeders and seed producers are highly... more
ABSTRACT Eucalyptus smithii is an important commercial forestry species in South Africa. The species’ shy and erratic flowering tendencies hinder its genetic improvement and seed production. Breeders and seed producers are highly dependent on paclobutrazol (PBZ) applications for encouraging flower and seed production in E. smithii orchards. During the summer of 2003/04, an E. smithii flowering field trial series was established across a range of high elevation (1568–1828 m asl), cool temperate (13.8–15.5°C mean annual temperature (MAT)) commercial forestry sites in South Africa. The main objective was to investigate the interaction between PBZ and a range of climatic and landscape factors on E. smithii floral bud (umbel) production. The main aim was to define optimum environmental conditions for E. smithii umbel production and potential orchard establishment. In the fifth and sixth years after planting, 64% and 83% of the control (nil PBZ) grafted trees and 94% and 94% of PBZ-treated trees produced umbels. In the fifth year, PBZ application increased mean (across-site) umbel production per tree by 132%. Regardless of whether PBZ was applied or not, mean umbel production varied markedly across sites. In the absence of PBZ application, E. smithii test orchards located on south-west facing slopes in high elevation (>1550 m asl) areas at the lower end of the applied MAT range were generally the most productive on the basis of umbel crop. The study demonstrated that, through careful site selection, dependency on PBZ to achieve satisfactory umbel production in reproductively mature E. smithii trees may be substantially reduced. Within the elevation and MAT ranges applied in the trial series, E. smithii orchards situated in low positions in the landscape were at high risk of being severely damaged by frosts.
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The agricultural sector is one of the crucial sectors heavily impacted by the consequences of water scarcity. Improved water resources management in croplands is important as available water resources become scarcer. Evaporation and... more
The agricultural sector is one of the crucial sectors heavily impacted by the consequences of water scarcity. Improved water resources management in croplands is important as available water resources become scarcer. Evaporation and transpiration are important processes in the hydrological cycle. Their quantification remains one of the important challenges for the agricultural and environmental sciences. Eddy covariance, a direct method of measuring fluxes, was used for estimating total evapotranspiration (ET) over maize and soybean crops in the KwaZulu-Natal midlands. Observed ET coupled with maize and soybean yields were used to determine water use efficiency for each crop for the entire growing season (2012/13). Thereafter, observed ET and crop yields were compared to the total ET and yield from simulations done using the FAO AquaCrop crop model. AquaCrop simulates attainable yields of several crops as a function of water use under rainfed, deficit of full irrigation conditions. ...
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Research Interests: Environmental Science, Computer Science, Chemistry, Analytical Chemistry, Water, and 15 morePolymers, Medicine, Energy Metabolism, Sensors, Vapor Pressure, Temperature, Relative Humidity, Pressure, Humidity, STEAM, Hygrometer, Water Vapor, Electrical And Electronic Engineering, Capacitive Sensing, and dew point
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Measurements of sensible heat flux for an extended period for unstable conditions using surface layer scintillometry (SLS) and eddy covariance (EC) and supplemented by Bowen ratio measurements for a mixed grassland community on the... more
Measurements of sensible heat flux for an extended period for unstable conditions using surface layer scintillometry (SLS) and eddy covariance (EC) and supplemented by Bowen ratio measurements for a mixed grassland community on the eastern seaboard of South Africa are presented. Measurements of SLS sensible heat flux density were compared with those obtained using EC for a wide range of Bowen ratio (β). Also presented is an analysis of the different forms of the Monin–Obukhov similarity theory (MOST) functions used in micrometeorology and suggested by various authors, done by comparing EC sensible heat and measured by SLS through the use of an iterative determination of Monin–Obukhov parameters. A comparison of the SLS-measured structure parameter of air temperature CT2 corrected for β and uncorrected was carried out, with the results showing good correspondence but with a slight bias indicating that not correcting SLS measurements of CT2 for β would also result in a slight bias in ...