Rainfall seasonality effects on vegetation greenness in different ecological zones

Abstract

This study assesses the spatial and temporal changes in precipitation and its effects on vegetation greenness over six ecological zones in Nigeria. Both vegetation and climatological satellite datasets were used for this study. Satellite climatological data include African Rainfall Estimation Algorithm (RFE) and Climate Hazards Group Infrared Precipitation with their respective Stations (CHIRPS), while Moderate Resolution Imaging Spectroradiometer (MODIS) was used to examine variations in vegetation greenness over time. Both rainfall variability estimation and the normalized difference vegetation index (NDVI) analysis were carried out. The results show that there is a significant spatiotemporal variation in precipitation in the different ecological zones. It is obvious that precipitation influences vegetation greenness in all ecological zones, but much more in Sahel and Sudan ecological zones. The results from correlation reveal a significant relationship between NDVI and CHIRPS with R2 > 0.50, especially in the Sahel, Sudan, and Guinea savannah ecological zones. The relationship between RFE and NDVI further revealed a slightly moderate degree of relationship with 0.40 < R2 > 0.49. This study demonstrates that precipitation has a significant influence on vegetation productivity and greenness. The study concludes on the note that rainfall seasonality determines variations in vegetation greenness to a significant extent in all the ecological zones.