Adeyeri OE*, Lamptey BL, Lawin AE and Sanda IS
This paper investigated the spatio-temporal trends and homogeneity analysis of rainfall over the Komadugu-Yobe basin using data from Nigerian Meteorological Agency (NiMet), Department of National Meteorology Niger (DMN) and a 10 km resolution gridded observation data from Princeton University (PGF) for the period 1979 and 2015. The data, analysed at the annual and seasonal (wet and dry seasons) timescales, were subjected to Mann-Kendal including modified Mann-Kendall trend test after testing for autocorrelation. Test for homogeneity was performed on the data using Pettitt’s, Buishand’s, Standard Normal Homogeneity Test and van Belle and Hughes’ test. An overall homogenous trend of rainfall series was observed in the basin for all the seasons considered using van Belle and Hughes’ homogeneity trend test. The global rainfall trend increases in the dry season and decreases in the annual and wet seasons for the period of study. Pettitt’s homogeneity test for the annual and wet season rainfall series showed that change points were detected in the year 2005 for nine grids out of fifteen over the basin at 5% significant level. This study therefore, shows the importance of understanding the spatial and temporal distribution and trends in rainfall for effective planning and management of water resources in the basin.
