Effective Onset Rainfall and Inter-seasonal Variability over Sokoto North-Western Nigeria

Abstract

The study investigates effective onset rainfall and its inter-annual variability over Sokoto, North West Nigeria. Daily rainfall data were collected from the archive of Environmental Management Programme, Federal University of Technology? Minna from 1971-2015. The data were aggregate into pentad and analysed with intra-seasonal rainfall monitoring index (1RMI). The inter-annual were determine by subtracting the succeeding onset from the previous. The results revealed one worst off year (1987) of onset (49 pentad) and one good year (1997) of onset (27 pentad). The general pattern of the rainfall has been erratic. The average onset rainfall in the study area was found to be 40 pentad (20 July). The implication of this is that the onset rainfall has been poor. Owing to high variability of onset date of rainfall, continue monitoring and communication of exact onset date to the rain-fed fanner is recommended.