Standardized Precipitation Index Comparison along the Limbe-Bamenda Axis of the Cameroon Gulf of Guinea

Mean monthly rainfall decline with continentality is a commonplace phenomenon that has been used in this study to compare its trend in Bamenda in the Western Highlands and Limbe on the Atlantic lowland coast. This study attempts to bridge some of the methodological gaps in the previous studies on rainfall variability in Cameroon that had emphasized only the inter-annual variability and coefficient of variation without focusing on the specific indices and contrasts between different ecological zones. In this study, a comparative analysis has been done of the standardized precipitation index (SPI) for Bamenda and Limbe, using data from 1985–2015. The analysis involved the mean annual rainfall (176.88 mm and 419.9 mm), its standard deviation (SD) (22.98 and 102.42), and the coefficient of variation (CV) (12.99% and 24.41%) for Bamenda and Limbe, respectively. The results show that the mean annual rainfall for Bamenda is decreasing, whereas that of Limbe is increasing. The mean SPI is –0.01 (mild dryness) and 0.02 (mild wetness) for Bamenda and Limbe, respectively. These results have far-reaching implications for the development of agriculture, water resources management, and other man-environment interaction variants.