AN ASSESSMENT OF SPATIO-TEMPORAL VARIABILIY OF DROUGHT IN THE SEMI-ARID ZONE OF NIGERIA USING STANDARDIZED PRECIPITATION INDEX.

Usman, S.U.*, Abdulhamid, A.I. and Sawa, B.A.

Drought is a recurrent phenomenon in Nigeria’s semi-arid zone especially in the last few decades. In this study, spatio-temporal variation of drought in this zone from 1976 to 2013 is investigated. Standardized Precipitation Index (SPI) is used to determine both the spatial and temporal dimensions of drought based on frequency and severity of drought events at 6-month time step. The study found that in the study area, the first two decades of the study period (1976-1985 and 1986-1995) are chequered by drought and non-drought events. During the decade that followed (1996-2005), drought events were also recorded but to a lesser degree. The latest period (2006- 2013) is almost free from drought events except for a moderate drought at Sokoto. Near normal condition, which is a situation whereby rainfall is slightly above or below normal, is recently becoming prevalent in the area. This is a clear indication that a significant shift towards a wetter condition is being experienced in the area. Nevertheless, it is recommended that even though some sort of respite from drought is being experienced in the area recently, a watchful eye should be kept on it, and its coping and mitigation measures always put in place.

Key words: Drought, Standardized precipitation index, Semi-arid, 6-month SPI.