Tshilidzi Manyanya | University of Venda (original) (raw)
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Papers by Tshilidzi Manyanya
Remote Sensing
The LCZ framework has become a widely applied approach to study urban climate. The standard LCZ t... more The LCZ framework has become a widely applied approach to study urban climate. The standard LCZ typology is highly specific when applied to western urban areas but generic in some African cities. We tested the generic nature of the standard typology by taking a two-part approach. First, we applied a single-source WUDAPT-based training input across three urban areas that represent a gradient in South African urbanization (Cape Town, Thohoyandou and East London). Second, we applied a local customized training that accounts for the unique characteristics of the specific area. The LCZ classification was completed using a random forest classifier on a subset of single (SI) and multitemporal (MT) Sentinel 2 imagery. The results show an increase in overall classification accuracy between 17 and 30% for the locally calibrated over the generic standard LCZ framework. The spring season is the best classified of the single-date imagery with the accuracies 7% higher than the least classified se...
Climate, 2021
Mopani District Municipality in the northeast of South Africa is largely semi-arid and frequently... more Mopani District Municipality in the northeast of South Africa is largely semi-arid and frequently affected by meteorological droughts. The recent 2015/16 event had devastating impacts on water levels, crop yields, livestock herds and rural livelihoods. We investigated the nature of the drought hazard; its impacts, including vulnerability of rural communities in Mopani District and adaptation strategies they have employed to cope with drought. A mixed methods approach with both quantitative and qualitative datasets was used. The district was divided into two distinct climatic areas: the drier eastern lowveld and the wetter western bushveld. Questionnaires were administered among community members whilst key informant interviews were conducted among relevant government and municipal officials. Climate data was used to characterize historical drought using a Standardized Precipitation and Evapotranspiration Index whilst vegetation anomaly maps were used to demonstrate impacts. Spatiall...
Weather and Climate Extremes, 2021
An extreme sub-daily precipitation event produced about 300 mm of rainfall in less than 4 h overn... more An extreme sub-daily precipitation event produced about 300 mm of rainfall in less than 4 h overnight from 13-14 February 2019 resulting in high floods in Thohoyandou, a small town northeast of South Africa. We employed station, radar, satellite and reanalysis datasets to investigate the rainfall, circulation and thermodynamic fields and understand the meteorological structure of the extreme event via a multiscale analysis. The large-scale synoptic environment was characterized by a mid-tropospheric tropical-temperate trough and attendant cloud band coupled to a surface high ridging over the southeast coast of the country. We found that whilst heavy rainfall (>50 mm/24 h) was widespread ahead of the upper trough, extreme amounts (~100 mm/ h) were localized due to a cloudburst. A small perturbation to the favorable large scale mid-tropospheric environment also contributed to localized heavy rainfall. The south-north pressure gradient was steepened by a surface low over southern Mozambique resulting in enhanced moisture fluxes deriving from the southwest Indian Ocean. The interaction of prevailing surface winds and a low-level jet with the steep topography of the adjacent Soutpansberg Mountain Range enhanced low-level convergence and lifting in the area. We also show that the highest rainfalls were uphill of the location of flooding which was contained in a poorly drained valley. Whereas the Unified Model forecasts appeared accurate for the large-scale pattern of heavy rainfall in the area, the rainfall peak was generally underestimated, whilst the timing of extreme rainfall was delayed in the 18Z simulation, which is used by forecasters operationally. Our findings contribute to understanding the occurrence of extreme weather events over northeastern South Africa and also how models treat them, towards natural disaster risk reduction.
Water, 2021
Climate change has increased the frequency of extreme weather events such as heavy rainfall leadi... more Climate change has increased the frequency of extreme weather events such as heavy rainfall leading to floods in several regions. In Africa, rural communities are more vulnerable to flooding, particularly those that dwell in low altitude areas or near rivers and those regions affected by tropical storms. This study examined flood vulnerability in three rural villages in South Africa’s northern Limpopo Province and how communities are building resilience and coping with the hazard. These villages lie at the foot of the north-eastern escarpment, and are often exposed to frequent rainfall enhanced by orographic factors. Although extreme rainfall events are rare in the study area, we analyzed daily rainfall and showed how heavy rainfall of short duration can lead to flooding using case studies. Historical floods were also mapped using remote sensing via the topographical approach and two types of flooding were identified, i.e., those due to extreme rainfall and those due to poor drainag...
4th International Conference on Advances in Agricultural, Biological & Ecological Sciences (AABES-16) Dec. 1-2, 2016 London, Dec 1, 2016
Agro-ecology has emerged as a front runner in food security and sovereignty, with the UNFCCC and ... more Agro-ecology has emerged as a front runner in food security and sovereignty, with the UNFCCC and FAO advocating its global adoption. Agro-ecological implementation is theorised to increase crop health and yield by 3-10 % in a space of 3-10 years. This study aimed to assess the practicality and validity of these assumptions using mainly GIS and remote sensing. Adopting a mixture of Ex-post-facto and Experimental designs necessitated the presence of a control element. Each agro-ecological farm was thus assessed and compared with a conventional farm in the same geographical conditions. Crop health was assessed using satellite images analysed through ArcGIS to produce NDVI and Reclassified outputs whereas yield was calculated from production records. The shift in NDVI-crop ranges indicates changes in crop health over time. Crop health and yield both showed a decrease over 80% of the conventional farms and an increase over 80% of the organic farms.
European Journal of Sustainable Development, 2014
Human social structures and their development significantly depend on the maintenance and conserv... more Human social structures and their development significantly depend on the maintenance and conservation of the environmental resources they require for survival. Forests have been known to be sources of raw materials and resources for sectors of human livelihoods such as healthcare, household uses and agriculture, among others. Understanding the influence of forests on agriculture not only improves the agricultural practices but also enhances eco-friendly development and sustainability. This paper investigates the relationship between forest edge microclimates and agricultural cropproduction. The study adopted a Bio-geographical approach buttressed on the Mono-Climax Theory (MCT) and Holdridge's Deterministic Approach (HAD). Data for this study comprised of agricultural cropproduction for 2012 collected from farmers along the edge of Thathe Forest in Limpopo, South Africa,in all the four cardinal directions. Vegetation density and composition from the forest edge in all the four cardinal directions was collected through quadrats. Linear regression between agricultural productivity, as the dependent variable, and vegetation composition and density, as independent variables, was employed to determine the relationship. Results reveal that agricultural crop production, vegetation density decrease andcomposition change as one moves from the forest edge. We conclude that Thathe forest creates an important micro-climate for agriculture. As such the forest should be conserved for sustainable agricultural production and development.
Human social structures and their development significantly depend on the maintenance and conserv... more Human social structures and their development significantly depend on the maintenance and conservation of the environmental resources they require for survival. Forests have been known to be sources of raw materials and resources for sectors of human livelihoods such as healthcare, household uses and agriculture, among others. Understanding the influence of forests on agriculture not only improves the agricultural practices but also enhances eco-friendly development and sustainability. This paper investigates the relationship between forest edge microclimates and agricultural cropproduction. The study
adopted a Bio-geographical approach buttressed on the Mono-Climax Theory (MCT) and Holdridge’s Deterministic Approach (HAD). Data for this study comprised of agricultural cropproduction for 2012 collected from farmers along the edge of Thathe Forest in Limpopo, South Africa,in all the four cardinal directions. Vegetation density and
composition from the forest edge in all the four cardinal directions was collected through quadrats. Linear regression between agricultural productivity, as the dependent variable,
and vegetation composition and density, as independent variables, was employed to determine the relationship. Results reveal that agricultural crop production, vegetation
density decrease andcomposition change as one moves from the forest edge. We conclude that Thathe forest creates an important micro-climate for agriculture. As such the forest
should be conserved for sustainable agricultural production and development.
Key terms: Micro-climate,Bio-geographical, sustainability, vegetation, agriculture.
Remote Sensing
The LCZ framework has become a widely applied approach to study urban climate. The standard LCZ t... more The LCZ framework has become a widely applied approach to study urban climate. The standard LCZ typology is highly specific when applied to western urban areas but generic in some African cities. We tested the generic nature of the standard typology by taking a two-part approach. First, we applied a single-source WUDAPT-based training input across three urban areas that represent a gradient in South African urbanization (Cape Town, Thohoyandou and East London). Second, we applied a local customized training that accounts for the unique characteristics of the specific area. The LCZ classification was completed using a random forest classifier on a subset of single (SI) and multitemporal (MT) Sentinel 2 imagery. The results show an increase in overall classification accuracy between 17 and 30% for the locally calibrated over the generic standard LCZ framework. The spring season is the best classified of the single-date imagery with the accuracies 7% higher than the least classified se...
Climate, 2021
Mopani District Municipality in the northeast of South Africa is largely semi-arid and frequently... more Mopani District Municipality in the northeast of South Africa is largely semi-arid and frequently affected by meteorological droughts. The recent 2015/16 event had devastating impacts on water levels, crop yields, livestock herds and rural livelihoods. We investigated the nature of the drought hazard; its impacts, including vulnerability of rural communities in Mopani District and adaptation strategies they have employed to cope with drought. A mixed methods approach with both quantitative and qualitative datasets was used. The district was divided into two distinct climatic areas: the drier eastern lowveld and the wetter western bushveld. Questionnaires were administered among community members whilst key informant interviews were conducted among relevant government and municipal officials. Climate data was used to characterize historical drought using a Standardized Precipitation and Evapotranspiration Index whilst vegetation anomaly maps were used to demonstrate impacts. Spatiall...
Weather and Climate Extremes, 2021
An extreme sub-daily precipitation event produced about 300 mm of rainfall in less than 4 h overn... more An extreme sub-daily precipitation event produced about 300 mm of rainfall in less than 4 h overnight from 13-14 February 2019 resulting in high floods in Thohoyandou, a small town northeast of South Africa. We employed station, radar, satellite and reanalysis datasets to investigate the rainfall, circulation and thermodynamic fields and understand the meteorological structure of the extreme event via a multiscale analysis. The large-scale synoptic environment was characterized by a mid-tropospheric tropical-temperate trough and attendant cloud band coupled to a surface high ridging over the southeast coast of the country. We found that whilst heavy rainfall (>50 mm/24 h) was widespread ahead of the upper trough, extreme amounts (~100 mm/ h) were localized due to a cloudburst. A small perturbation to the favorable large scale mid-tropospheric environment also contributed to localized heavy rainfall. The south-north pressure gradient was steepened by a surface low over southern Mozambique resulting in enhanced moisture fluxes deriving from the southwest Indian Ocean. The interaction of prevailing surface winds and a low-level jet with the steep topography of the adjacent Soutpansberg Mountain Range enhanced low-level convergence and lifting in the area. We also show that the highest rainfalls were uphill of the location of flooding which was contained in a poorly drained valley. Whereas the Unified Model forecasts appeared accurate for the large-scale pattern of heavy rainfall in the area, the rainfall peak was generally underestimated, whilst the timing of extreme rainfall was delayed in the 18Z simulation, which is used by forecasters operationally. Our findings contribute to understanding the occurrence of extreme weather events over northeastern South Africa and also how models treat them, towards natural disaster risk reduction.
Water, 2021
Climate change has increased the frequency of extreme weather events such as heavy rainfall leadi... more Climate change has increased the frequency of extreme weather events such as heavy rainfall leading to floods in several regions. In Africa, rural communities are more vulnerable to flooding, particularly those that dwell in low altitude areas or near rivers and those regions affected by tropical storms. This study examined flood vulnerability in three rural villages in South Africa’s northern Limpopo Province and how communities are building resilience and coping with the hazard. These villages lie at the foot of the north-eastern escarpment, and are often exposed to frequent rainfall enhanced by orographic factors. Although extreme rainfall events are rare in the study area, we analyzed daily rainfall and showed how heavy rainfall of short duration can lead to flooding using case studies. Historical floods were also mapped using remote sensing via the topographical approach and two types of flooding were identified, i.e., those due to extreme rainfall and those due to poor drainag...
4th International Conference on Advances in Agricultural, Biological & Ecological Sciences (AABES-16) Dec. 1-2, 2016 London, Dec 1, 2016
Agro-ecology has emerged as a front runner in food security and sovereignty, with the UNFCCC and ... more Agro-ecology has emerged as a front runner in food security and sovereignty, with the UNFCCC and FAO advocating its global adoption. Agro-ecological implementation is theorised to increase crop health and yield by 3-10 % in a space of 3-10 years. This study aimed to assess the practicality and validity of these assumptions using mainly GIS and remote sensing. Adopting a mixture of Ex-post-facto and Experimental designs necessitated the presence of a control element. Each agro-ecological farm was thus assessed and compared with a conventional farm in the same geographical conditions. Crop health was assessed using satellite images analysed through ArcGIS to produce NDVI and Reclassified outputs whereas yield was calculated from production records. The shift in NDVI-crop ranges indicates changes in crop health over time. Crop health and yield both showed a decrease over 80% of the conventional farms and an increase over 80% of the organic farms.
European Journal of Sustainable Development, 2014
Human social structures and their development significantly depend on the maintenance and conserv... more Human social structures and their development significantly depend on the maintenance and conservation of the environmental resources they require for survival. Forests have been known to be sources of raw materials and resources for sectors of human livelihoods such as healthcare, household uses and agriculture, among others. Understanding the influence of forests on agriculture not only improves the agricultural practices but also enhances eco-friendly development and sustainability. This paper investigates the relationship between forest edge microclimates and agricultural cropproduction. The study adopted a Bio-geographical approach buttressed on the Mono-Climax Theory (MCT) and Holdridge's Deterministic Approach (HAD). Data for this study comprised of agricultural cropproduction for 2012 collected from farmers along the edge of Thathe Forest in Limpopo, South Africa,in all the four cardinal directions. Vegetation density and composition from the forest edge in all the four cardinal directions was collected through quadrats. Linear regression between agricultural productivity, as the dependent variable, and vegetation composition and density, as independent variables, was employed to determine the relationship. Results reveal that agricultural crop production, vegetation density decrease andcomposition change as one moves from the forest edge. We conclude that Thathe forest creates an important micro-climate for agriculture. As such the forest should be conserved for sustainable agricultural production and development.
Human social structures and their development significantly depend on the maintenance and conserv... more Human social structures and their development significantly depend on the maintenance and conservation of the environmental resources they require for survival. Forests have been known to be sources of raw materials and resources for sectors of human livelihoods such as healthcare, household uses and agriculture, among others. Understanding the influence of forests on agriculture not only improves the agricultural practices but also enhances eco-friendly development and sustainability. This paper investigates the relationship between forest edge microclimates and agricultural cropproduction. The study
adopted a Bio-geographical approach buttressed on the Mono-Climax Theory (MCT) and Holdridge’s Deterministic Approach (HAD). Data for this study comprised of agricultural cropproduction for 2012 collected from farmers along the edge of Thathe Forest in Limpopo, South Africa,in all the four cardinal directions. Vegetation density and
composition from the forest edge in all the four cardinal directions was collected through quadrats. Linear regression between agricultural productivity, as the dependent variable,
and vegetation composition and density, as independent variables, was employed to determine the relationship. Results reveal that agricultural crop production, vegetation
density decrease andcomposition change as one moves from the forest edge. We conclude that Thathe forest creates an important micro-climate for agriculture. As such the forest
should be conserved for sustainable agricultural production and development.
Key terms: Micro-climate,Bio-geographical, sustainability, vegetation, agriculture.