Spatio-Temporal Analysis of Rainfall Pattern and Vegetation Dynamics in Kogi State, Nigeria

Abstract

The spatio-temporal analysis of rainfall and vegetation dynamics of Kogi State have been studied over 33years (1983-2016). These years was divided into three intervals, viz: 1983-1990, 1991-2000, and 2001-2016 denoted as 80s, 90s and 00s respectively. The Tropical Application of Meteorology Using Satellite and ground based Observation (TAMSAT) monthly RFE (Rainfall Estimate) and Anomaly data and monthly GIMMS (Global Inventory Modeling and Monitoring Studies) NDVI monthly data all covering the period 1983-2016 was used in this study. The aim of the study is to ascertain how the spatial and temporal changes in rainfall over the years was analyzed using ARCGIS 10.3 and maps were produced for the respective intervals stated above. Also, spatial distribution of rainfall anomaly was analyzed with ARCGIS 10.3 and maps were as well produce. The GIMMS NDVI data was equally subjected to ARCGIS in order to know the spatial distribution and dynamism of vegetation over the years in the study area. The relationship between rainfall and vegetation indices of the State was determined using regression analysis. Results shows that the extreme north western and southern part of the state experienced high rainfall in the 80s, the central region of the state had moderate rainfall, while the northern part experienced low rainfall. In the 90s, only the southern part experienced high rainfall (1241.09-1410.29mm), the north eastern experienced a reduction (as they had moderate rainfall unlike the 80s where they had high) having moderate rainfall with the central region (1025.06-1123.26mm). In the 00s, almost all the Local Government Areas experienced the same rainfall amount with the 90s except an increase experienced by Yagba East and West. In the 80s, North western, Central and Northern experienced positive anomaly (-30.03-30.46mm) while the South eastern, Southern and Northern part experienced negative anomaly (-81.68 – -30.03mm). In the 90s, Southern, South-eastern and Central experienced positive (-11.52-25.17mm) while the North-western had negative (-43.62 – -11.52mm). In the 00s, the North-western, Northern and South-eastern experienced positive (20.60-50.52mm) while the Southern and Central region experienced negative (2.686-26.60mm).