Forecast Analysis of Hydro-climatic Data of Nouhao Sub-basin in East-Central of Burkina Faso

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Résumé

Forecast analysis of hydro-climatics data of Nouhao Sub-Basin shows how useful local rain gauges data collected by population during 4 to 7 years in three (03) villages on the experimental site for the local planning and forecasting. The first results show that i) the breakdown of the series determines the seasonality and occurrence of "casual" rains; ii) the auto-correlation detection test showed that casual rains are not self-correlated and validates the model; iii) the dry/rainy season cycle is from mid-October to April and from mid-April to mid-October for this experimental site, iv) the forecasts for N+1 years in 2016, 2017 and 2018, compared to the collected data, clearly show that the statistical forecast model is robust. The level of correlation is satisfactory with a positive correlation coefficient close to unity. The deficit of cumulative rainfall average around to 14%. The 2019 forecast shows a deficit compared to the previous year (2018). It is a dry year compared to the average index for the period 2012-2018. However, the 2019 forecast for the experimental area corroborates well with the Permanent Interstate Committee for Drought Control in the Sahel (ICDS/CILSS) forecasts indicating a normal to surplus year with pockets of drought in the second part of the season for part of Burkina Faso. Longer monitoring in the basin would contribute to seasonal forecasting efforts in Burkina Faso.

Mots-clés

seasonal rainfall forecasting, precipitation deficit, statistical forecasting models, Sahel drought, Burkina Faso