Spatial and Temporal Trends of Extreme Precipitation in Eastern Africa during January 1981-2023

Extreme precipitation events pose significant challenges to water resources, agriculture, infrastructure, public health, ecosystems, energy production, fishing, timber production, and other rain-dependent socioeconomic sectors across Eastern Africa, threatening the environment and regional livelihoods. This study analyzes spatial and temporal trends of extreme precipitation in Eastern Africa from January 1981 to 2023, using high-resolution CHIRPS data. Key extreme precipitation indices, including R10mm, R75p, and SDII, were calculated to assess variations in the frequency, intensity, and contribution of extreme rainfall events. The temporal analysis reveals a statistically significant increasing trend in January precipitation (0.844 mm/year, p = 0.0191), confirmed by Sen’s Slope (0.74 mm/year). R10mm increased by 0.036 days/year (p = 0.0079), with Sen’s Slope estimating 0.04 days/year. R75p showed a rise of 0.025 days/year (p = 0.0113), with Sen’s Slope at 0.02 days/year. SDII exhibited the most significant trend, increasing by 0.056 mm/day per year (p = 0.0002), with Sen’s Slope at 0.06 mm/day per year. These results indicate a rise in extreme precipitation in Eastern Africa, increasing the risk of flooding and other climate-related hazards. Spatial analysis shows distinct regional variations, with Southern Tanzania, Mozambique, Malawi, Zambia, Zimbabwe, and Madagascar exhibiting statistically significant increasing trends in January precipitation and extreme precipitation indices. These regions are becoming more vulnerable to flooding and other climate-related hazards. Moreover, correlation analysis identifies significant links between global SST anomalies and extreme precipitation trends, demonstrating the influence of large-scale climate drivers. The study indicates the growing intensity and frequency of extreme precipitation in parts of Eastern Africa, significantly influenced by the South Pacific Convergence Zone (SPCZ). This necessitates a deeper understanding of SPCZ dynamics and their impacts on precipitation patterns to enhance climate prediction and develop adaptive strategies for mitigating extreme weather events. Such efforts will contribute to safeguarding water resources, agriculture, infrastructure, public health, energy production, fisheries, transportation, and livelihoods across the region.