Assessing the Variability of Heavy Rainfall Events during Gu Rainfall Season in Somalia

Abstract

The occurrence of heavy rainfall is a significant contributing factor to the occurrence of flooding in Somalia during the rainy season, resulting in substantial socio-economic consequences. This study investigates the spatial-temporal variations of Heavy Rainfall Events (HREs) occurring from March to May (MAM), commonly referred to as the Gu rainy season, in Somalia from 1991 to 2020. The analysis employed the Empirical Orthogonal Function method to investigate the spatial-temporal variations of HREs. The findings indicate that there is an unequal distribution HREs throughout the country, with the southern regions exhibiting the highest concentration of HREs of about 340 HREs, while the northwestern regions had a relatively lower number of HREs. It was found that there is a notable variation in HREs on a monthly basis, with April and May exhibiting a higher prevalence compared to March, which appears to have a lower impact. The prevalence of HREs has been seen to be more prominent and rapidly escalating, particularly in the southern region, with a statistically significant level of 95%. Moreover, it has been found that the recurrence rate of HREs in the southern region of the country is around once every decade, whilst in the central region, the average return time of HREs is three years. Conversely, the northern region experiences HREs on an almost annual basis. Therefore, it is imperative to comprehend the spatial and temporal variations of heavy rainfall in order to effectively strategize agricultural practises and implement mitigation measures for extreme weather phenomena such as droughts and floods.

Rainfall Variability; Heavy Rainfall Events; Gu Rainfall Season; Somalia