GEOSPATIAL ANALYSIS OF RAINFALL PATTERNS

ABSTRACT

This study conducts a geospatial assessment of rainfall patterns in Edo State spanning the years 1982 to 2022. The aim is to examine the possibility of significant changes in rainfall patterns within this time frame. The study area, Edo State, situated in the rainforest vegetation zone is a midwestern state in Nigeria. Data on average rainfall from 1982-2022 were collected from the Climate Hazards Group Infrared Precipitation with Station data (CHIRPS). Additionally, rainfall records for the years 2040 to 2060 were extracted from downscaled future climate data associated with the Coupled Model Intercomparison Project 6 (CMIP6). The data was analyzed, producing mean values (maximum, minimum, and average) and standard deviations using QGIS 3.8. Findings reveal a notable trend in average annual rainfall from 1982 to 2022. The study observed an increase in average annual rainfall over time, with figures rising from 1677.82 mm in 1982 to 1756.5 mm in 1992. Subsequently, peak values of 1875.03mm in 2002 and 1857.51mm in 2012 were recorded, followed by a decline, resulting in an average rainfall of 1718.81 mm in 2022. Projections indicate a further increase to 1905.45 mm by the year 2050. The Chi-square test was employed to assess significant differences across the studied year intervals, affirming the presence of significant changes in rainfall patterns. This study establishes that the rainfall pattern in Edo State has undergone significant changes during the study period and stakeholders and policymakers in Edo State should consider these evolving patterns in water resource management, agriculture, and flood risk mitigation and adaptation strategies for the region.