Rainfall Variability and the Recent Climate Extremes in Nigeria

Abstract

Recently, large and extended weather and climate extremes were recorded in different parts of the country, causing significant socio-economic impacts. Weather patterns affecting the country are driven by the  northward and southward movement of the Inter-Tropical Discontinuity (ITD) as well as developments within the pressure systems created by the two distinct wind regimes north and south of the ITD. The climate of  Nigeria, in particular, the Sahel zone, is characterized by multiyear  persistence of anomalously wet and dry conditions. Climatic and statistical analyses were employed to investigate two extreme events, flood and droughts, in the last four decades. The results showed variations in rainfall across the various climatic zones in the country. In particular, flood and drought episodes were identified. Observation showed that the savannah and semi-arid areas of Nigeria have suffered from inter-annual to seasonal climatic variabilities and there have been droughts and effective desertification processes, particularly since the 1960s. It was further noted that these variations in rainfall usually showed completely different patterns within the same climatic zones and that stations located relatively close to one another exhibited different patterns of rainfall. Analysis of rainfall anomalies and maximum temperature departures in the last five years brought out some clues to the spate of recent and wide spread of flooding across the country. Therefore, the recent incursion of floods, in parts of the country seriously threatened lives and property, important business centres and agricultural farm lands and was a classical example of the danger that could be posed by weather and climate extremes.