Spatial distribution and temporal trends in precipitation concentration indices over Burkina Faso from 1993 to 2023

Understanding the spatial distribution of rainfall is essential for organising the agricultural calendar and managing water resources in river basins. This study aims to analyse rainfall concentration in Burkina Faso between 1993 and 2023. To this end, daily rainfall data for this period were obtained from the National Meteorological Agency of Burkina Faso. These data were collected from ten synoptic and climatological stations. The data were then processed using the ‘precintcon’ package in RStudio. Temporal data for concentration indices, such as precipitation concentration index (PCI), precipitation concentration period (PCP) and precipitation concentration degree (PCD), were extracted for analysis. Methods such as interpolation, the Mann–Kendall test, and linear regression were applied to the data. The study shows that PCI, annual PCD and decadal PCD are distributed irregularly throughout the year between 1993 and 2023, following a north–south gradient. Furthermore, the periods of concentrated rainfall that occur during the rainy season are spread across the arid, steppe, and Hot (Bsh) zones. This implies that maximum rainfall occurs during the rainy season in these zones, which is not the case in the other climate zones. The study also reveals that PCI and PCD exhibit interannual variability, with a slight upward trend between 1993 and 2023. This situation poses a significant risk of soil erosion and water stress, resulting in poor seedling emergence and disruption to the agricultural calendar.