Two phases of long-term shift in extreme precipitation in Somalia

The occurrences of some intense rainfall episodes in Somalia in recent years, resulting in flash floods in riverine areas, prompted researchers to investigate the significance of long-term shifts in severe rainfall across Somalia in the past century. The study aimed to examine the changes in precipitation trends in Somalia by carrying out an analysis of the frequency of rainfall extremes during the two different phases 1901–1958 and 1959–2016, as well as return level analysis. The Mann–Kendall test and Sen’s slope were used to measure the changes in precipitation trends. The generalized extreme value distribution was also fitted to the two phases considered in the analysis. The study revealed that heavy rainfall events and flood risks are becoming more common in Somalia. Furthermore, the behavior of extreme rainfall has evolved over the two phases considered. This evolution is shown by the presence of change in distribution (using Kolmogorov–Smirnov and Anderson Darling tests) in phase I (1901–1958) and phase II (1959–2016) and the significant difference in the maximum likelihood estimates of the location parameter for the two phases. The findings provide some intriguing results that will be beneficial to hydrological planning and disaster management.