Latest News Archive

Please select Category, Year, and then Month to display items

SA now experiencing half-year summers

12 October 2020 | Story Leonie Bolleurs | Photo Supplied

Although several international studies have used temperature metrics to statistically classify their seasonal divisions, a study in which Adriaan van der Walt was involved, would be the first known publication in a South African context using temperature as classification metric.

Gone are the days when we as South Africans would experience a three-month spring season, easing into summer, and then cooling off for three months before we hit winter.

Adriaan van der Walt, Lecturer in the Department of Geography at the University of the Free State (UFS), focuses his research on biometeorology (a specialist discipline exploring the role and climate change in physical and human environments) as well as climatology and geographic information systems.

He recently published an article: ‘Statistical classification of South African seasonal divisions on the basis of daily temperature data’ in the South African Journal of Science.

In this study, which Van der Walt undertook with Jennifer Fitchett, a colleague from the University of the Witwatersrand, data on daily maximum and minimum temperatures was collected from 35 meteorological stations of the South African Weather Service, covering the period between 1980 and 2015.

They went to great lengths to ensure that they had a complete set of data before presenting it to demonstrate seasonal brackets.

First for South Africa

Their statistical seasonal brackets indicate that South Africans now experience longer summers (from October to March), autumn in April and May, winter from June to August, and spring in September.

Although considerable work has been done using rainfall to determine seasonality in Southern Africa, Van der Walt believes that these methods did not work well as there are too many inconsistencies in this approach, as identified by Roffe et al. (2019, South African Geographical Journal). To make matters more complicated – as a semi-arid region, and with desert conditions along the west coast – some regions do not have enough rainfall to use as a classifier.

Temperature, on the other hand, worked well in this study. “Temperature, by contrast, is a continuous variable, and in Southern Africa has sufficient seasonal variation to allow for successful classification,” says Van der Walt.

He continues: “Although several international studies used temperature metrics to statistically classify their seasonal divisions, this study would be the first known publication in a South African context using temperature as classification metric.”

Van der Walt says what we understand as seasons largely relates to phenology – the appearance of blossoms in spring, the colouration and fall of leaves in autumn, and the migration of birds as a few examples. “These phenological shifts are more sensitive to temperature than other climatic variables.”

Seasonal brackets

According to Van der Walt, they believe that a clearly defined and communicated method should be used in defining seasons, rather than just assigning months to seasons.

“One of the most important arguments of our work is that one needs to critically consider breaks in seasons, rather than arbitrarily placing months into seasons, and so we welcome any alternate approaches,” he says.

A number of sectors apply the temperature-based division to their benefit. “For example, in the tourism sector it is becoming increasingly important to align advertising with the season most climatically suitable for tourism,” says Van der Walt.

Temperature-based division is also used to develop adaptive strategies to monitor seasonal changes in temperature under climate change. However, Van der Walt points out that each sector will have its own way of defining seasons. “Seasonal boundaries should nevertheless be clearly communicated with the logic behind them,” he says.

News Archive

UFS boasts with most advanced chemical research apparatus in Africa

2005-11-23

Celebrating the inauguration of the NMR were from the left Prof Frederick Fourie (Rector and Vice-Chancellor of the UFS), Dr Detlef Müller (Development Scientist and Manager: Africa and Asia of Bruker in Germany, the supplier of the NMR), Prof Jannie Swarts (head of the head of the Division Physical Chemistry at the UFS) and Prof Herman van Schalkwyk (Dean: Faculty of Natural and Agricultural Sciences at the UFS). Photo: Lacea Loader

UFS boasts with most advanced chemical research apparatus in Africa

The University of the Free State’s (UFS) Department of Chemistry now boasts with some of the most advanced chemical research apparatus in Africa after the latest addition, a nuclear magnetic resonance (NMR) spectrometer, was inaugurated today by the Rector and Vice-Chancellor, Prof Frederick Fourie. The NMR is used to analyse molecular structures.

Last month the Department of Chemistry celebrated the installation of the most advanced single crystal X-ray diffractometer in Africa. The diffractometer provides an indispensable technique to investigate among others the solid state of compounds for medicinal application.

“Three years ago the UFS executive management realised that, if we want to build a university of excellence, we should invest in research. We started to think strategically about chemistry and decided to bring the apparatus at the Department of Chemistry on a more competitive standard. Strategic partnerships were therefore secured with companies like Sasol,” said Prof Fourie during the inauguration ceremony.

“The installation of the NMR symbolises the ability of the UFS to turn academic areas around. I hope that this is the beginning of a decade of excellence for chemistry at the UFS,” said Prof Fourie.

”The catalogue value of the Bruker 600 MHz NMR is approximately R11 million. With such an advanced apparatus we are now able to train much more post-graduate students,“ said Prof Jannie Swarts, head of the Division Physical Chemistry at the UFS.

”The NMR is the flagship apparatus of the UFS Department of Chemistry that enables chemists to look at compounds more easily at a molecular level. Research in chemistry is critically dependent on NMR, which is a technique that can determine the composition of reactants and products in complicated chemical reactions, with direct application is most focus areas in chemistry,“ said Prof Swarts.

”Parts of the spectrometer consists of non-commercial items that were specifically designed for the UFS Department of Chemistry to allow the study of unique interactions in e.g. rhodium and platinum compounds,” said Prof Swarts.

According to Prof Swarts the NMR enables chemists to conduct investigations on the following:

To evaluate for example the complex behaviour of DNA in proteins as well as the analysis of illegal drugs sometimes used by athletes.
It provides an indispensable technique to investigate compounds for medicinal application for example in breast, prostate and related bone cancer identification and therapy, which are currently synthesised in the Department of Chemistry.
It can also be applied to the area of homogeneous catalysis where new and improved compounds for industrial application are synthesized and characterised, whereby Sasol and even the international petrochemical industry could benefit. This analytical capacity is highly rated, especially in the current climate of increased oil prices.
The NMR can detect and identify small concentrations of impurities in feed streams in the petrochemical industry, e.g. at Sasol and also the international petrochemical industry. These minute amounts of impurities can result in metal catalyst deactivation or decomposition and can cause million of rands worth in product losses.
It is indispensable for studying the complexity of samples that is non-crystalline. These materials represent the vast majority of chemical compounds such as solvents, gasoline, cooking oil, cleaning agents and colorants as examples.

According to Prof Swarts the general medical technique of MRI (magnetic resonance imaging) in use at larger hospitals, is based on NMR technology.

”The NMR apparatus enabled the Department of Chemistry to characterise complex molecules that were synthesised for the multi-national company, FARMOFS-PAREXEL, and to negotiate research agreements with overseas universities,” said Prof Swarts.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
22 November 2005

Back

Economic and Management Sciences

Education

Health Sciences

The Humanities

Law

Natural and Agricultural Sciences

Theology and Religion

Open Distance Learning

Business School

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept