Analysis of rainfall and temperature time series to detect long-term climatic trends and variability over semi-arid Botswana

  • Jimmy Byakatonda
  • B P Parida
  • Piet K Kenabatho
  • D B Moalafhi


Arid and semi-arid environments have been identified with locations prone to impacts of climate variability and change. Investigating long-term trends is one way of tracing climate change impacts. This study investigates variability through annual and seasonal meteorological time series. Possible inhomogeneities and years of intervention are analysed using four absolute homogeneity tests. Trends in the climatic variables were determined using Mann–Kendall and Sen’s Slope estimator statistics. Association of El Niño Southern Oscillation (ENSO) with local climate is also investigated through multivariate analysis. Results from the study show that rainfall time series are fully homogeneous with 78.6 and 50% of the stations for maximum and minimum temperature, respectively, showing homogeneity. Trends also indicate a general decrease of 5.8, 7.4 and 18.1% in annual, summer and winter rainfall, respectively. Warming trends are observed in annual and winter temperature at 0.3 and 1.5% for maximum temperature and 1.7 and 6.5% for minimum temperature, respectively. Rainfall reported a positive correlation with Southern Oscillation Index (SOI) and at the same time negative association with Sea Surface Temperatures (SSTs). Strong relationships between SSTs and maximum temperature are observed during the El Niño and La Niña years. These study findings could facilitate planning and management of agricultural and water resources in Botswana.


Correlation El Niño homogeneity test intervention analysis persistence trend analysis 



This study was supported by the Mobility for Engineering Graduates in Africa (METEGA) and Carnegie Cooperation of New York through RUFORUM in the form of research funds. The climatic data used were provided by Department of Meteorological Services (DMS) of Botswana. The authors are grateful for the support from the two entities. Gulu University is highly appreciated for granting study leave to the first author. They also wish to thank the two anonymous reviewers for their valuable comments that enriched this study.


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Copyright information

© Indian Academy of Sciences 2018

Authors and Affiliations

  • Jimmy Byakatonda
    • 1
    • 3
  • B P Parida
    • 1
  • Piet K Kenabatho
    • 2
  • D B Moalafhi
    • 2
  1. 1.Department of Civil EngineeringUniversity of BotswanaGaboroneBotswana
  2. 2.Department of Environmental ScienceUniversity of BotswanaGaboroneBotswana
  3. 3.Department of Biosystems EngineeringGulu UniversityGuluUganda

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