List of research themes and overview

The NWU boasts a suite of operational tools for the seamless prediction of weather across scales. Using the latest community driven tools, such as the Thunderstorm Identification, Tracking, Analysis and Nowcasting (TITAN), the Weather Research and Forecasting Model (WRF), the Global Forecasting System (GFS) and the latest generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5-Reanalysis data the NWU is able to provide a suite of data products ranging from now-casting (0-15min) products for thunderstorm tracking, high resolution, in house, weather forecasts from 12 - 72 hours in advance, and climate products to better understand the long term trends and cycles of any particular region.

Lekwena Radar 

The North-West University (NWU) acquired a decommissioned WSD-88 weather radar in 2014. The project was funded by the Water Research Commision (WRC) to improve rainfall estimates in the Mooi River Catchment through a suite of instruments that allowed for high spatial and temporal analysis of rainfall events in the region. The selected site’s proximity also meant that the radar covered major metropolitan areas in Gauteng, North-West and the Free-State. This means that the NWU-Lekwena radar covers several economically important areas, from the highly populated economic hub of Johannesburg, to the mining rich regions in eastern North-West and the major farming regions in the North-West and Northern Free-State. The radar was officially commissioned by the late Minister of Environmental Affairs, Edna Molewa, in Potchefstroom on 22 March 2018. Since this time the radar has been used as a testbed for new forecasting and tracking algorithms, while capturing the severe thunderstorms and rainfall events over the Highveld.

A Living Weather Laboratory (https://www.lekwenaradar.co.za/)

Numerical Weather Prediction

The Weather Research and Forecasting Model (WRF) is an advanced, community driven, and open source weather model that can be used for both operational forecasting and meteorological research at a variety of scales. Along with The NWU-Lekwena Radar, The NWU-WRF puts the North-West University Potchefstroom at the forefront of numerical weather prediction research in Africa, as the only university running an in-house, student driven operational weather radar and an operational numerical weather prediction model. The model runs on a daily basis and provides a 48 hour weather forecast for the Southern Africa region. 

Weather Modification

The NWU is involved in research and development of software for the identification and targeting of convective storm clouds. Research around weather modification mainly involves the characterisation and identification of clouds that are suitable for seeding. This involves building accurate climatologies of seedable clouds, research into convective processes and cloud dynamics, and the microphysics and composition of clouds. 

Pyrogeography and Fire Climatology

The African continent has for years been termed the ‘Fire Continent’ due to the high number of fires that occur. Fire has also long been utilised as a management tool by the agricultural sector in what is known as ‘prescribed burning’.  The development of remote sensing technologies has allowed for the study of fires at a greater spatial resolution in the context of vegetation communities and topography in a changing climate. Fires will always be a natural phenomenon in environmental systems. However, increased fire disasters due to anthropogenic activities are having a negative impact on the environment and more so on society and the economy. Southern Africa has a varied climate in terms of rainfall and air temperature. The sub-Saharan region of Africa also has distinct wet and dry seasons, which have a notable influence on fire activity. Atmospheric conditions greatly influence the occurrence and development of wildfires. Atmospheric conditions which are warmer and drier result in a higher “fire danger”. As a result, the impacts of climate change on fire activity and fire danger also requires attention. Climate variability will result in changing fire regimes which needs to be studied.  

Climate Change in Under-represented, High-priority Areas of South Africa

A wealth of information on the extent and severity of global climate change has been produced through research over the past few decades. Global climate change trends should be observable at a regional and local level, yet certain areas remain under-represented in both national and international research. For example, arid and semi-arid regions comprise roughly 30% of the earth’s surface, and in 2000, a total of 14.4% of the global population resided in semi-arid regions alone. While semi-arid/arid regions provide marginal resources for agriculture (particularly crops), a number of economic and social factors have resulted in these areas becoming central to global agricultural productivity. A total of 63% of South Africa’s croplands are located in semi-arid regions with the Free State accounting for 32%, the North West accounting for 17%, and Mpumalanga accounting for 14%. The largest percentage of farmland in South Africa is found in the Northern Cape, where most of the land is used for livestock agriculture. As agriculture in South Africa predominantly occurs in the sensitive and marginal semi-arid/arid regions, it is vital to understand the rates of change of the climate in these highly sensitive and important areas as small changes could result in significant changes in land use.

Taken from: Strydom et al. (2019): Long-term trends and variability in the dryland microclimate of the Northern Cape Province, South Africa. Theoretical and Applied Climatology. https://doi.org/10.1007/s00704-018-2642-y

Climate Change and Water Resources

With a semi-arid climate, the country receives an average of roughly 470 mm of rainfall a year. Additionally, the mean annual runoff of the country is only about 50 × 109 m3 per annum. In South Africa, water resources are generally comprised of surface and subsurface runoff, largely influenced by rainfall variability. The annual rainfall of most parts of South Africa also tends to display high levels of spatio-temporal variability. While the underlying mechanisms of climate change are well-understood, the potential impacts on various sectors are less clear. Even when impacts are well-understood, variability in magnitude and timing can be uncertain. Evaporation, for example, is known to be dependent on air temperature and relative humidity. A change in evaporation is expected as the overall climate changes. Additionally, changes in rainfall seasonality, coupled with increased evapotranspiration is expected to further stress water supply. A warmer atmosphere is likely to enhance rainfall variability. The relationship between atmospheric warming and water vapour storage is likely to reduce rainfall in some areas, while other areas may experience an increase. At smaller spatial scales, the impact of climate change on rainfall is less clear. Understanding climate variability and change is thus of utmost importance in the context of water resources.

List of Research Themes and Overview

At the NWU Vanderbijlpark campus, we have a state of the art Automatic Weather Station (AWS) which observes standard meteorological parameters in real time whilst also part of the network of observing stations of the South African Weather Service. The AWS is also equipped with sensors that monitor key air quality indicators as the Vaal is a region of significant industrial activities and therefore pollution levels are likely to be higher. 

Automatic weather station at NWU Vanderbijlpak Campus

Extreme Weather and Climate

Research at the NWU Vanderbijlpark ranges across time and space scales from sub-daily events to climate change timescales. Climate change has increased the frequency and intensity of extreme events. Several examples of severe droughts, intense heat waves, heavy thunderstorms leading to floods and also cold conditions associated with snowfalls. Our research analyzes extreme weather and climate events to understand the driving dynamics and also how models treat them. Often tropical cyclones, cut off lows and severe thunderstorms lead to loss of lives and livelihoods and destruction of expensive infrastructure. Whilst we may not prevent them, we can at least improve the ability of weather models in forecasting them thereby contributing to natural disaster risk reduction. We have also found that South Africa’s complex topographic features often exacerbate extreme events.  

At seasonal time scales, droughts often affect large areas of South Africa and we seek to understand the meteorological processes associated with drought. In addition to analyzing the circulation fields, we have also found strong links between hot spots over the oceans and drought in the region. For example we have found that drought over eastern South Africa occurs during El Nino conditions and when sea-surface temperatures over the western tropical Indian Ocean are anomalously warmer. Tropical cyclones that affect the eastern provinces of South Africa during the late summer are also regulated by the sea-surface temperature anomalies among other variables. Thus, we conduct research to assess the performance of climate models to simulate drought conditions during the austral summer. Ensembles of climate models are  

Climate Change, Impacts, Vulnerability and Adaption

We seek to understand how changes in land cover affect the boundary layer climate of regions of significant land use and land cover change. Changes in land cover lead to changes in albedo and the partitioning of surface heat and moisture fluxes and evapotranspiration. We attribute these changes via multivariate analysis and the use of climate sensitivity tests using climate models run with and without land cover. Sensitivity experiments are important to test the role of certain processes in the climate system.

We also investigate impacts of climate change on food systems, water resources and rural livelihoods. Rapidly rising surface air temperatures have led to increased evaporation of water from open water bodies and from exposed soils thereby affecting crop and livestock production. As the fire season is lengthened due to delayed onset of the summer rains, we investigate how fire regimes are evolving as the climate changes. The risk of Heat waves also affect human health by altering the blood circulation and therefore the heart rates which may cause serious conditions in the vulnerable. This also affects the availability of farm labour. Our interest is to find out how vulnerable rural communities are to impacts of climate change and also how they are adapting or living with a new climate. It is also important to evaluate the success or sustainability of an adaptation strategy. Ultimately, our research seeks to contribute to sustainable development and natural disaster risk reduction, in a changing climate.