Isolines of Rainfall Kinetic Energy and Intensity in Nigeira.

Abstract

Based on the power law equations developed by Salako (2006; 2007; 2008), daily rainfall data (generally 1988-2005) were collected from 17 weather stations in Nigeria (representing all agroecological zones in the country) to compute kinetic’ energy of rainfall and IS-minute intensity, 1/5. The Wischmeicr and Smith (1978) kinetic index. EWS was similar to Brown and Foster (1987) index, E-BF. Isolines of rainfall kinetic energy and intensity were drawn with SURFER Version 8. Kinetic energy and rainfall intensity increased, generally, from the coastal region of the southeast in the northwestward direction. There were, however, abrupt changes in both characteristics between latitude 7 and lION, mainly in the derived, southern Guinea (SGS) and northern Guinea (NGS) savannas. Sholi-term rainfall intensities could be similar among regions in spite of significant differences in cumulative rainfall amount or kinetic energy. Kinetic energy measured at a monthly scale showed less spatial variation than that on daily scale, suggesting that long timescale could obscure useful details. Rainfall erosivity trends across the country suggest a possible influence of the migration of the Intertropical Convergence Zone (ITCZ). The maps presented can be used to decide spacing for locations of monitoring centers for soil and water management in the country.