Long-range predictablity of Zimbabwe summer rainfall

Unganai, Leonard; Mason, Simon J.

The potential for long‐range prediction of Zimbabwe summer rainfall is investigated using an analysis of variance approach. It is assumed that the variance between seasons (inter‐annual variability) is made up of two components: the climate noise (intra‐seasonal variability) and signal (any variance above the noise). The magnitude of the climate noise is estimated by computing the variance of time‐averaged rainfall data based on a statistical model whose parameters are derived from observed daily values at each station. Results from the study indicate that up to approximately 70% of the total variance in Zimbabwe summer rainfall is potentially predictable at long range. Predictability is greatest during the last half of the rainy season, January to March, and much lower during October to December. The south section of the country shows relatively more predictability than the north. Comparisons between signal and noise are discussed in the context of long‐range predictability. The natural variability (noise) is proposed as a lower limit of the standard error of the estimate for any long‐range precipitation forecast for the country.

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Also Published In

International Journal of Climatology

More About This Work

Academic Units
International Research Institute for Climate and Society
Published Here
March 23, 2020