Effects of El Nino/Southern Oscillation (ENSO) on rainfall characteristics in Katsina, Nigeria

Annual rainfall amount, onset and termination dates, duration of the rainy season, the number of wet and dry days and August rainfall characteristics in Katsina, Nigeria were compared between the ENSO years, La Niña years and normal years over a period of 31 years (1972 - 2002). In ENSO years annual rainfall amount is lower than the long term mean, onset is later and the termination of the rainy season is earlier than the normal years. Duration is shorter during ENSO years than other years and August rainfall is lower in ENSO years. Generally, precipitation index (PI) indicates that ENSO years particularly 1972/73 and 1982/83 coincided with drought years in the area. Since there is some empirical relationship between ENSO and rainfall in Katsina, Nigeria, it would be possible to predict extreme rainfall events like drought if the periodicity of ENSO can be understood.