Spatio-temporal analysis of extreme rainfall indices in Burkina Faso using RClimDex
- African Geographical Review , 46 (1) : 1-32
Résumé
This study examines extreme precipitation trends across Burkina Faso’s Sahelian, Sudano-Sahelian, and Sudanian zones from 1991 to 2023, amid growing hydro-climatic variability in West Africa. The aim is to determine whether changes in rainfall extremes reflect gradual trends, structural shifts, or both. Three indices were analyzed: maximum 1-day precipitation (RX1day), maximum consecutive 5-day precipitation (RX5day), and the Simple Daily Intensity Index (SDII), using a non-parametric framework combining Mann – Kendall trends, Sen’s slope, and Pettitt change-point tests (p < 0.05), with spatial patterns mapped via GIS. Results show a latitudinal contrast. In the Sahelian zone, Dori recorded a significant SDII change in 2004 (p = 0.040) followed by increasing intensity. The Sudano-Sahelian zone exhibits the strongest signal: Ouagadougou shows upward trends in RX5day and SDII with a structural break in 2006. The Sudanian zone remains stable, dominated by interannual variability. Overall, climate change manifests mainly through intensified rainfall energy and multi-day accumulations. The 2004–2006 period marks a national hydro-climatic turning point, emphasizing rising flood risks in central urban areas.
Mots-clés
Extreme precipitation; climate change; hydro- climatic variability; Burkina Faso