Long-Term Changes in Rainfall Regime, Extremes, and Intra-Area Spatial Heterogeneity over the Menkao Region, Kinshasa (DRC), Using CHIRPS Satellite-Based Precipitation Data (1981–2025)

Understanding rainfall-regime change in rapidly expanding African urban and peri-urban areas is essential for flood-risk reduction, drainage planning, erosion control, and climate-sensitive territorial management. This study analyses long-term rainfall variability, extremes, dry–wet structure, and intra-area spatial heterogeneity over the Menkao region of Kinshasa, Democratic Republic of the Congo, using daily Climate Hazards Group InfraRed Precipitation with Station data from 1981 to 2025. Daily spatial mean, minimum, and maximum rainfall were extracted in Google Earth Engine and analysed through a reproducible Python workflow combining trend detection, rainfall-extreme indices, change-point analysis, drought and wetness diagnostics, quantile-based assessment, and extreme-value modelling. The results show that annual rainfall totals exhibit only a weak and non-robust long-term trend, indicating that the main hydroclimatic signal is not a simple increase in total rainfall. In contrast, heavy rainfall indicators strengthened more consistently. Days with at least 20 millimetres increased by approximately 1.25 days per decade, while high-end wet-day rainfall percentiles also increased, confirming a strengthening of heavy rainfall events. The longest wet spell declined by about 1.05 days per decade, suggesting shorter but more intense wet sequences. Intra-area rainfall heterogeneity increased as well, with wet-day spatial amplitude rising by approximately 0.322 millimetres per decade and showing a regime shift around 2012–2013. December emerged as the main monthly hotspot of change. Overall, Menkao appears to be undergoing a reorganisation of rainfall behaviour marked by stronger extremes, shorter wet spells, and greater spatial unevenness rather than a clear increase in annual rainfall totals.