Patterns of Meteorological Drought Using Standardized Precipitation Evapotranspiration Index for Massili Basin, Burkina Faso

As a Semi-arid country, Burkina Faso is highly vulnerable to climate-related disasters such as drought and flood. Analyzing drought signature is therefore a key factor in advocating climate change adaptation at the local scale. In this study, Spatiotemporal trends of drought were conducted for the period 1960–2021 within Massili Basin using the standardized precipitation and evapotranspiration index (SPEI) package in R. The non-parametric method (Mann–Kendall) was then used to test for a monotonic trend, whereas the magnitude was estimated using Sen's method. Accordingly, the result revealed that during the period 1960-1979, the mean value of SPEI varies from 0.06 to 0.71; over 1980 to 2009, the mean value of the SPEI varies from -0.08 to -0.88 and for the last decades (2010 to 2021), the mean value of the SPEI ranges from 0.05 to 0.75. Normal to middle wet conditions is thus observed over the periods 1960-1979 and 2010-2021 while the period (1980-2009) depicts a middle drought condition. The Mann-Kendall test results show a decreasing trend of SPEI-3 and SPEI-24 with a Z value of - 0.784 and -0.530 respectively. A slightly increasing trend is observed for SPEI-6 and SPEI-12 with Z ranging from 0.598 to 1.917 respectively. The magnitude of the decrease is indicated by the sens’ slope value, which is -0.0014 for SPEI-3 and -0.00010 for SPEI-24 while the magnitude of the increase ranges from 0.00011 for SPEI-6 to 0.00037 for SPEI-12. This study highlights the importance of examining past drought features to obtain essential information to assist in designing and implementing efficient water resources management strategies over the Massili Basin.