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 and Mexico forge links

2006-03-30

Some of the guests attending the signing of the memorandum of agreement were in front from the left Prof Wijnand Swart (Chairperson: Centre for Plant Health Management at the UFS), His Excellency Mauricio de Maria y Campos (Ambassador of Mexico in Southern Africa), Prof Magda Fourie (Vice-Rector: Academic Planning at the UFS) and Dr José Sergio Barrales Domínguez (Rector of the University of Chapingo in Mexico).
Photo: Stephen Collett

UFS and Mexico forge links
The Centre for Plant Health Management (CePHMa) in the Department of Plant Sciences at the University of the Free State (UFS) is presenting its first international conference. The conference started yesterday and will run until tomorrow (Friday 31 March 2006) on the Main Campus in Bloemfontein.

The conference is the first on cactus pear (or prickly pear) in South Africa since 1995. It coincides with 2006 being declared as International Year of Deserts and Desertification by the United Nations General Assembly.

During the opening session of the conference yesterday a memorandum of understanding (MOU) was signed between CePHMa and the University of Chapingo (Universidad Autonoma Chapingo) in Mexico. The signing ceremony was attended by the Ambassador of Mexico in Southern Africa, His Excellency Mauricio de Maria y Campos, the Rector of the University of Chapingo, Dr José Sergio Barrales Domínguez, and the Vice-Rector: Academic Planning of the UFS, Prof Magda Fourie, amongst other important dignitaries.

“South Africa and Mexico have a lot in common where agricultural practices in semi-arid areas and the role of the cactus pear are concerned,” said Prof Wijnand Swart, Chairperson of CePHMa at the opening of the conference.

He said that the MOU is the result of negotiations between CePHMa and the Ambassador of Mexico in Southern Africa over the past 12 months.

“The MOU facilitates the negotiation of international cooperative academic initiatives between the two institutions. This entails the exchange of students and staff members of the UFS, curriculum development, research and community service,” said Prof Swart.

“During the next two days, various areas of interest will be discussed. This includes perspectives from commercial cactus pear farmers in South Africa, the health management of cactus pear orchards, selection of new cultivars of cactus pear, and the nutritional and medicinal value of the crop,” said Prof Swart.

In his welcoming message Prof Swart explained that in recent years there has been increased interest in the cactus pear for the important role it can play in sustainable agricultural systems in marginal areas of the world. These plants have developed phenological and physiological adaptations to sustain their development in adverse environments.

“The cactus pear can serve as a life saving crop to both humans and animals living in marginal regions by providing a highly digestible source of energy, water, minerals and protein,” said Prof Swart.

“In an age when global warming and its negative impact on earth’s climate has become an everyday subject of discussion, the exploitation of salt and drought tolerant crops will undoubtedly have many socio-economic benefits to communities inhabiting semi-arid regions,” said Prof Swart.

“Plantations of cactus pear grown for fruit, forage and vegetable production, as well as for natural red dye produced from the cactus scale insect known as cochineal have, over the last two decades, been established in many countries in South America, Europe, Asia and Africa. The crop and its products have not only become important in international markets, but also in local markets across the globe,” said Prof Swart.

Detailed discussions on the implementation of the MOU will take place between CePHMa and the University of Chapingo after the conference.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
30 March 2006

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