Spatio-temporal Analysis of Rainfall Variability in Loumbila Municipality, Central Plateau, Burkina Faso

Abstract

This study analyzes rainfall data collected in the Municipality of Loumbila, located in Burkina Faso's Central Plateau, over a 30-year period (1992-2022). The analysis reveals significant precipitation variability, characterized by alternating wet years and drought periods. This irregularity manifests as highly variable rainfall: annual totals dropping abruptly from over 800 mm to under 500 mm, with seasonal onsets and offsets delayed by 2-4 weeks. It reflects the unstable rainfall regime typical of Sahelian zones under variable intertropical monsoon influence. The methodology employs a 30-year rainfall series (1992-2022) from ANAM, analyzed using non-parametric tests (Mann-Kendall for trends, Pettitt for breaks, Q-Q/P-P plots for normality) and SPI to quantify droughts. Application of the Standardized Precipitation Index (SPI) reveals increased frequency of prolonged dry spells impacting water availability and rain-fed vegetable production. These rainfall fluctuations reduce agricultural productivity and heighten food vulnerability among rural households. Consequently, adaptation strategies emphasizing rainwater management and agricultural planning are essential to enhance Loumbila Municipality's climate resilience.