Indigenous knowledge in seasonal rainfall prediction in Tanzania : a case of the South-western Highland of Tanzania

Early and significant flowering of Mihemi (Erythrina abyssinica) and Mikwe (Brachystegia speciformis) trees has been identified as a signal of good rainfall in the South-western Highland of Tanzania. Farmers have singled out the behaviour of the Dudumizi bird as another indicator. This study was conducted in Rungwe and Kilolo districts in Mbeya and Iringa regions. Systematic documentation and integration of indigenous knowledge into conventional weather forecasting is a recommended strategy for improving the accuracy and reliability of seasonal rainfall forecasts under increasing climate variability. Since agriculture in Tanzania is mainly rainfed, where, when and what to plant depends on the accuracy of rainfall forecasting

Spatial and Temporal Analysis of Rainfall and Temperature Extreme Indices in Tanzania

Climate extreme indices in Tanzania for the period 1961-2015 are analyzed using quality controlled daily rainfall, maximum and minimum temperatures data. RClimdex and National Climate Monitoring Products (NCMP) software developed by the commission for Climatology of the World Meteorological Organization (WMO) were used for the computation of the indices at the respective stations at monthly and annual time scales. The trends of the extreme indices averaged over the country were computed and tested for statistical significance. Results showed a widespread statistical significant increase in temperature extremes consistent with global warming patterns. On average, the annual timescale indicate that mean temperature anomaly has increased by 0.69˚C, mean percentage of warm days has increased by 9.37%, and mean percentage of warm nights has increased by 12.05%. Mean percentage of cold days and nights have decreased by 7.64% and 10.00% respectively. A non-statistical significance decreasing trends in rainfall is depicted in large parts of the country. Increasing trend in percentage of warm days and warm nights is mostly depicted over the eastern parts of the country including areas around Kilimanjaro, Dar-es-Salaam, Zanzibar, Mtwara, and Mbeya regions. Some parts of the Lake Victoria Basin are also characterized by increasing trend of warm days and warm nights. However, non-statistical significant decreasing trends in the percentage of warm days and warm nights are depicted in the western parts of the country including Tabora and Kigoma regions and western side of the lake Victoria. These results indicate a clear dipole pattern in temperature dynamics between the eastern side of the country mainly influenced by the Indian Ocean and the western side of the country largely influenced by the moist Congo air mass associated with westerly winds. The results also indicate that days and nights are both getting warmer, though, the warming trend is much faster in the minimum temperature than maximum temperature.The paper is publishedThe authors wish to thank The Tanzania Meteorological Agency for providing data used in this study and WMO for providing guidance in the analysis of climate extreme in climate time series