Abstract:
The spatio-temporal analysis of drought in the Sudano-Sahelian region of Nigeria has been carried
out in this study. Analysis of 10 years Moderate Resolution Imaging Spectroradiometer (MODIS)
NDVI data and 46 years precipitation data obtained from Nigeria Meteorological Agency
(NIMET), reveals 22 years of drought occurrences in the study area for the 12 months Standardised
Precipitation Indx (SPI) analysis. Extreme drought situation was observed in 1973, 1983 and 1987.
The duration and severity of the drought of the 80’s are observed to be more devastating. Three
months (July-September), six months (May – October) and August SPI analysis was also carried
and varying degree of drought conditions were revealed.
Mean monthly NDVI ranged from 0.135 to 0.141 across the study area. The NDVI values greater
than 0.135 corresponded well with the rainy season from May to September. Monthly NDVI for
the month of August and September are close in value as the rate at which NDVI changes in the
study area with the onset and cessation of rainfall is slow. The equation for the relationship
between NDVI and Rainfall in this region has been established as RRmean = 723.57NDVImean+
15.937. The obtained positive and significant correlation between the NDVI and Rainfall [R2 =
0.63] indicates the close coupling between rainfall and land surface response patterns over the
region. This could be a useful tool in mean monthly rainfall estimation over the region. The NDVI
anomaly is observed to be similar to that of rainfall, as both have shown positive anomalies in
most of the years and weak negative anomalies in few years.
The study has provided useful information on the spatial and temporal extent of the prominent
drought episodes in the study area. Such information could be helpful in effective planning of rainfed
agriculture within the Sudano-Sahelian region of Nigeria.
