Analysing Spatial Variability of Monsoon Rainfall over West Africa

Abstract

Climate variability and changes have become a topic of increasing importance in recent decades due to extreme climate events such as floods and droughts, which profoundly impact socioecological systems across West Africa during the monsoon months. This study analyses and updates rainfall variability and spatial trends during these crucial months using monthly gridded rainfall data from 1950 to 2022. We applied the ordinary least square regression test, Buishand's, Standard normal homogeneity and Pettitt's tests for trend and change point detection analyses at a 5% significant level. The spatial variability and trends in rainfall were examined across three time periods: 1950-2022, 1963-1992, and 1993-2022. Change-point detection analysis revealed that there had been significant changes in the monsoon months' rainfall variability within the study period except in August. The detection of both positive and negative trends, representing trends toward wetter and drier conditions respectively, provides valuable insights for understanding and managing the impacts of climate variability and change for the most vulnerable areas.