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

---

Résumé

Understanding the spatial distribution of rainfall is essential for organising the agricultural calendar and managing waterresources in river basins. This study aims to analyse rainfall concentration in Burkina Faso between 1993 and 2023. To thisend, daily rainfall data for this period were obtained from the National Meteorological Agency of Burkina Faso. Thesedata 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), precipitationconcentration period (PCP) and precipitation concentration degree (PCD), were extracted for analysis. Methods such asinterpolation, the Mann–Kendall test, and linear regression were applied to the data. The study shows that PCI, annualPCD and decadal PCD are distributed irregularly throughout the year between 1993 and 2023, following a north–southgradient. 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 notthe case in the other climate zones. The study also reveals that PCI and PCD exhibit interannual variability, with a slightupward trend between 1993 and 2023. This situation poses a significant risk of soil erosion and water stress, resulting inpoor seedling emergence and disruption to the agricultural calendar.

Mots-clés

Precipitation concentration index, Precipitation concentration degree, Precipitation concentration period, Trend analysis, Spatial distribution · Burkina Faso