Characterization of the Sahelian and Guinea Savannah ecosystem of Nigeria based on land surface temperature and normalized difference vegetation index

Drought and desertification are expected to increase in Sahelian Africa, where there are significant rainfall deficits and extreme temperatures. This study examined the trends in vegetation and climate variables during the period 1986–2023 in Kano, Katsina and Jigawa states, Nigeria. We used Landsat 5 TM, 7 ETM ⁺ and 8 OLI/TIRS and processed spectral indices with Google earth engine platform. For the pilot site in Kano, the year 2015 had the highest minimum (40.19°C), maximum (43.04 °C) and mean (42.63 °C) land surface temperatures (LST), while 2005 had the lowest of these values. The LST for the three states showed a long-term increase over the study years but the normalized difference vegetation index in 1986 was generally low, being 0.19 in Kano, 0.15 in Katsina and 0.17 in Jigawa states, becoming lower still in 2010. Low vegetation condition index close to 0 was dominant in the three study sites, suggesting typically poor vegetation growth and coverage. Mild to severe drought was noticed in Jigawa state, while Kano and Katsina experienced mild drought. Continuous monitoring of these indices would be necessary to assess the overall health of the vegetation, providing insights into environmental changes and their potential impacts on the ecosystem.