Climate Variability and Meteorological Drought Incidences in Sokoto, Nigeria

Abstract

The paper attempted to determine the direction of climate variability in Sokoto using rainfall parameter. It also undertook an in-depth analysis of meteorological droughts in the study area using different time scales. The study made use of 64 years unbroken rainfall data spanning the period 1915 to 1979, obtained from the office of Nigerian Meteorological Services Department, Oshodi, Lagos. A five year moving average was used to establish climate swing direction, while the Standardization Precipitation Index (SPI) technique with time scale 3(J,A,S), 6(M,J,J,A,S,O) and 12 (Jan to Dec) were used for the drought analysis. Results obtained shows that rainfall is on the decrease in Sokoto. Analysis of the 3 month SPI shows that rainfall between the months of July to August is relatively constant and if crops were grown within this period, drought incidents would be unheard of in Sokoto. The 6 months SPI covers May to October and the result shows that precipitation deficiency varies from near normal to severe dry conditions. The 12 months SPI covers January to December and the result reveals a great inter annual variability. The research observes that drought is a time variant occurrence. For example, drought analysis shows that there was enough rainfall for crop growth within the growing season (May to October) in the years 1925, 1940, 1972 and 1975, yet, annual SPI values (January to December) shows that they were drought years with varying magnitude. The research concludes that drought analysis techniques should always be compared with yield figures for a proper understanding of drought measuring efficacy. Appropriate recommendations where proffered.