ANALYSIS OF RAINFALL VARIABILITY IN AKOKA, LAGOS STATE USING REMOTE SENSING DATA

Abstract

This study examined the spatial and temporal variability of rainfall in Akoka, Lagos State, over a 31-year 
period (1993–2023), using CHIRPS satellite-derived rainfall data analyzed in QGIS across 20 synoptic 
stations. The temporal assessment showed that rainfall was highest between 2003 and 2012, followed by a 
gradual decline from 2013 to 2022. Variability analysis using the Coefficient of Variation (CV) indicated 
moderate year-to-year fluctuation, with CV values ranging from 12% to 18%, confirming that rainfall in 
Akoka is variable but not extremely unstable. Seasonal rainfall, measured from March to November, was 
generally consistent, although individual years such as 2003, 2008, and 2019 showed higher variability. 
Monthly averages revealed June, July, September, and October as the wettest months, while January and 
December remained the driest with minimal spatial differences across the area. Spatial rainfall maps 
showed a clear gradient across Akoka, where tighter contour spacing reflected areas of sharper rainfall 
change and wider spacing indicated more uniform distribution. Annual totals ranged from 1,085 mm in 
2001 (the driest year) to 2,364 mm in 2019 (the wettest year). Analysis of major El Niño episodes 
demonstrated that their influence on rainfall in Akoka is inconsistent: events such as those in 1997-1998 
and 2015-2016 corresponded with reduced rainfall, while others, including 2002-2003 and 2009-2010, did 
not produce any decline. Overall, the findings highlight the complex behavior of rainfall in Akoka and 
underscore the need for continuous climate monitoring and proactive water-resource planning.