Abstract

Land surface temperature and vegetation cover are two vital climatic variables that change independently of each other. Global concern over climate change has however necessitated the need to study how the change in any one of the variables affects the other. This work is aimed at assessing the spatio-temporal trend of the relationship between vegetation cover and land surface temperature, concerning the Northern Guinea Savanna vegetation zone of Adamawa state, Nigeria. Twenty years (2000 to 2019) data series of Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data (MOD09A1), the day time land surface temperature data (MOD11A) and the night time land surface temperature (MYOD11A1) were used to spatially compute the Normalized Difference Vegetation Index (NDVI) and day-time and night-time Land Surface Temperature (LST) for each of the respective years of the study period. Both the day-time and night-time LST were correlated with the NDVI using simple linear regression analysis. The temporal analysis of the results indicates nonlinear changes in both the NDVI, day-time LST and nighttime LST. The results also indicate a negative correlation between LST and NDVI in both cases. The day-time result gives a vegetation cover reduction of 0.0063 per kelvin change in LST with fitting coefficient R2 = 0.3026 whereas the night-time results indicate a reduction of 0.0103 vegetation cover per kelvin rise in LST with a fitting coefficient R2 = 0.3697. The relatively low coefficient of determination is considered to be a result of other intervening variables such as the variation in the land surface emissivity and the station elevation.

Keywords: Land Surface Temperature (LST); Moderate Resolution Imaging Spectroradiometer (MODIS); Normalized Difference Vegetation Index (NDVI); Northern Guinea savanna