Southern Africa Temperatures

UPDATE 2 September 2017.  Three urban centres replaced by two small towns (De Aar and Songea).

Published data were used to analyse the long-term annual temperature trends at six locations located in southern Africa.   Stations selected were located in South Africa, Tanzania and Mozambique.

The data used were all from the website of KNMI (the Royal Netherlands Meteorological Institute). Only raw data were used (ie as originally recorded, without any adjustments). Data used were all from stations located in rural areas or in small towns so as to avoid the possible influence of urbanisation on the temperatures.

 

 

The periods of the data ranged from 35 years to 81 years of complete annual data.  The earliest record, at Beira, commenced in 1913.

The plots shown below are of the annual mean temperatures at each of the six locations. On each plot a polynomial “best fit” trendline has been added. It should be noted that the trendlines near each extremity (ie near the start and end of the records) are quite sensitive to individual data points, whereas trendlines within the main body of the record are much more stable and reliable.

 

COMPARISON OF TRENDLINES

Annual Mean Temperature Trends

[ The basis of these trendlines can be seen from the analyses for the seven individual stations – see next section. ]

 

 

Annual Mean Temperature Residual Trends

[ The individual trend-lines have been adjusted by constant amounts to be approximately zero at the trend-lines around 1980.

 

 

ANNUAL MEAN TEMPERATURE TRENDS FOR INDIVIDUAL STATIONS

Upington (South Africa ) 1940-2015

upington

 

De Aar (South Africa) 1941-2015

 

Pietersburg (South Africa) 1933-2015

pietersburg

 

Inhambane (Mozambique) 1931-2013

 

inhambane

 

Beira (Mozambique) 1913-2014

beira

 

Songea (Tanzania) 1951-2-15

 

 

DISCUSSION AND COMMENTS

  • The data analysed was limited to that which were available on the KNMI website.
  • The annual mean temperature trend-lines for six stations located in South Africa, Tanzania and Mozambique and showed cyclical, but different, patterns.  Five of the stations (excluding Upington) had Lows or a plateau around 1980 and Highs around 2000-2010.
  • Upington was an exception with a Low around 1950 and a High around 2000.
  • The increase in temperature from ~1980 to ~2010 was generally about 0.5-1.0 deg C.
  • Prior to ~1980 the temperature trends were variable, with the temperature in ~1940 being generally about 0.5 deg C below that in ~1980.

 

CONCLUSIONS

  • The trend-lines for the six stations are cyclical but variable.
  • Most stations had a Low or plateau around 1980.
  • Upington was an exception, having a cyclical trend-line but with a Low around 1990 and a High around 2000.
  • The increase in temperature from ~1980 to ~2010 was generally about 0.5-1.0 deg C.

 

The Author:

This article was written by Brian Gunter of Narooma, NSW. In his previous life Brian was an engineering hydrologist involved over many years in the analysis of rainfall and river flow data for the planning of water resources projects in Australia, Asia and Africa. In recent years he has been one of the Marine Rescue NSW (previously Royal Volunteer Coastal Patrol) volunteer weather observers who operate the Narooma station for the Bureau of Meteorology.

 

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