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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

“Breakthroughs depend on people believing in their own ideas”

2015-07-23

TED is a renowned international non-profit organisation dedicated to disseminating “ideas worth spreading” in the form compelling talks lasting up to 18 minutes.

Lerothodi Molete’s vision is to witness the youth of Bloemfontein emerge at the forefront of technological, scientific, and entrepreneurial innovations in both South Africa and the global arena.

Molete and Bonginkosi Leeuw are the organisers of TEDxUFS. Their duty is centered on inspiring people to believe in, and express, their ideas. These University of the Free State students have taken it upon themselves to inspire the youth to “push the boundaries of society.”

The second TEDxUFS event to be hosted by the university presents a unique opportunity for students, staff members, and the general public to mingle with influential speakers from across various disciplines.

Details of the event:

Date: Saturday 1 August 2015

Time: 08:00- 18:00

Venue: Albert Wessels Auditorium, Bloemfontein Campus

The keynote speakers include: Mmusi Maimane (Federal Leader: Democratic Alliance), Gareth Cliff (Radio personality: Cliff Central), Pieter Geldenhuys (Futurist), Brian Kally (Director: Arrow Logistics), Jonathan Jansen (Vice-Chancellor and Rector: UFS), Ricardo Peach (Director: Vrystaat Arts Festival, Pamela Nomvete (Former actor and writer), Gil Oved (Founder: Creative Counsel), Pepe Marais (CEO: Joe Public), Angelo Mockie (Senior Officer: Student Affairs and musician), Philippa Tumubweinee (Senior Lecturer in Architecture: UFS), and Melody Mentz (Psychology Senior Professor: UFS).

The reason behind the #AskWhy theme

"Why is a small word but it’s a quick, broad, sharp and abrupt one,” explains Leeuw. “It is the chosen word of the non-conformist, the defiant, and the visionary. It is a confrontational word. It challenges what is thought to be impossible.”

The ability to interrogate reality is what society and economies are built on. The absence of the fear to question encourages the capacity to progress.

Motivating young people to follow their dreams is the reason why the TEDxUFS team is persistent in their endeavours. Molete believes that, in order to change anything, people need to ask why.

Background of the innovation powerhouse called TED(x)

TED is a renowned international non-profit organisation dedicated to disseminating “ideas worth spreading” in the form compelling talks lasting up to 18 minutes.

In 1984, it was introduced as a conference exploring Technology, Entertainment, and Design. Three decades later, TED covers a wide variety of topics of global significance, reflecting the contemporary era in more than 100 languages.

TEDx events are under the TED umbrella. These events are organised independently, and create a platform for deliberating on local matters. The programme assists communities, organisations, and individuals to stimulate critical dialogue.

On 25 July 2014, the UFS hosted its inaugural TEDxUFS conference at the Odeion theatre on the Bloemfontein Campus, where eleven speakers addressed an audience of 150 people on interdisciplinary topics ranging from economics to entrepreneurship, technology, art, design, and theology.

This year, 200 seats will be available for innovative revolutionary individuals in search of inspiration.

Tickets are available at 0619284253 / 079 381 4126. Prices: R80 (Student/scholars) and R350 (Public/staff)

LINKS:

Lerothodi Molete- http://whoswho.co.za/lerothodi-molete-742022

Bonginkosi Leeuw- https://www.ted.com/tedx/events/10499

TEDxUFS- http://kovsielife.ufs.ac.za/templates/archive.aspx?news=276

Mmusi Maimane- http://whoswho.co.za/mmusi-maimane-44612

Garett Cliff- http://www.garethcliff.com/

Pieter Geldenhuys- http://pietergeldenhuys.com/

Brian Kally- https://za.linkedin.com/pub/brian-kally/4b/888/959

Jonathan Jansen- http://www.ufs.ac.za/adhoc-pages/rectorate/prof-(jd)-jonathan-jansen

Ricardo Peach- http://ricardopeach.com/

Pamela Nomvete- http://whoswho.co.za/pamela-nomvete-4789

Gil Ovid- https://za.linkedin.com/pub/gil-oved/3/910/892

Pepe Marais- http://joepublic.co.za/people

Angelo Mockie- https://za.linkedin.com/pub/angelo-mockie/27/56/302

PhilippaTumubweinee- http://natagri.ufs.ac.za/templates/staffmember.aspx?DCode=101&pid=zyNJm7KI%2b1k%3d

Melody Mentz- https://za.linkedin.com/in/melodymentz

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