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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

Prof. Letticia Moja a winner in her category

2004-08-17

Prof. Moja a finalist in award
'Every member of staff is important to me'

Michelle Cahill - Bloemnuus

IF you are in need of a dose of inspiration, try and get an appointment with Prof. Letticia Moja, the Dean of the Faculty of Health Science at the University of the Free State. It will not be easy as she has an extremely tight schedule, over and above being a finalist in the 2004 Shoprite/Checkers Woman of the Year competition.

Although not a born and bred Free Stater, this dynamic woman has come to love the Free State. "Once you get past the mindset of a small town and all the negatives surrounding it, it is an absolutely wonderful experience," Moja said.

Moja was born in Pretoria and grew up in Garankuwa as the second eldest of five children. "That was nothing special. I was not the eldest and I wasn't the youngest," she quipped. She had two younger brothers, one of whom died in a car accident and then two sisters.

She went to school in Pretoria and her first contact with the Free State was when she wrote her matric at Moroka High School in Thaba Nchu. "That was one of the best schools for us at that time," she says. After completing matric, she went on to study medicine in KwaZulu-Natal.

In 1982 she returned "home" and completed her internship at the Garankuwa Hospital. Hereafter she specialised in gynaecological obstetrics at Medunsa.

She became the head of the gynaecological obstetrics unit and later opened a branch in Pietersburg.

"This was just about the most heart-rending time of my life. You saw people travelling for up to three days just to see a doctor," she says. "Here we really interacted with the community."

In 2001 she was invited by the University of the Free State to apply for the job of vice-dean of the Faculty of Health Science. "I wasn't too keen," she says, "but they kept on calling to find out if I had applied or not," she says with a smile. "Eventually I gave in and was appointed."

She thought she would work a couple of years under Prof. Kerneels Nel, then the dean of the faculty. "Unfortunately that was not to be. I had hoped that I could learn from him," Moja says.

Prof. Nel died of a heart attack in 2003 after which Moja deputised for him before being appointed as dean.

"This brought along a whole newset of challenges," she says, "Now I have to work out budgets and I need to know what human resources are," she jokes. This has prompted her to take up her studies again and she is currently doing her MBA.

"It has certainly been a challenge to go into management and without my support structure I most certainly wouldn't have been able to do it," Moja says.

Moja is actively involved in her church and serves on various committees including the Health Professional Council where she is acting president of the Medical and Dental Board and the Provincial Aids Council.

To her no job is menial. She recalls when she used to have "high tea" with her staff in Gauteng and Limpopo. "One of the cleaning ladies used to think her job was menial. That is just not so. No hospital can do without even the lowest position. Imagine stepping over rubbish while you're trying to catch a baby. To me everybody is important no matter what you do. "

Moja's eldest daughter is studying for her B.Accounting degree at Wits . Her youngest daughter is in Gr. 9 at Eunice and she has also brought along her niece, who is in Gr. 8 at Eunice. "You see, we need to be three girls in the house."
She feels honoured to have been nominated by the institution especially as it is traditionally male-dominated. "It is not about me, but about the support structure. Nobody can do it on their own. It is a team effort."
BLOEMNUUS - VRYDAG 9 JULIE 2004

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