Drought analysis using normalized difference vegetation index and land surface temperature over Niamey region, the southwestern of the Niger between 2013 and 2019

Semi-arid regions are highly susceptible to drought due to their low annual precipitation and ecological vulnerability to climate change. This study focuses on the Niamey region in southwestern Niger and employs the Vegetation Health Index (VHI) to assess drought severity and its changes. Using data from the Landsat 8 OLI/TIRS, including the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST), we derived the Vegetation Condition Index (VCI), Temperature Condition Index (TCI), and Vegetation Health Index (VHI) for 2013 and 2019. Analysis of the Vegetation Health Index (VHI) time series for 2013 and 2019 reveals that the region experienced severe drought, with 62.31 km2 and 42.35 km2, respectively, facing a lack of precipitation. Notably, extreme droughts in 2019 covered a large area of 55.75 km2, accounting for 13.94 % of the region, indicating an increase in drought frequency from 2013 to 2019. Furthermore, the NDVI values for the study area in 2013 ranged from 0.50 to - 0.18, while those in 2019 ranged from 0.57 to - 0.20. Additionally, the relationship between LST and NDVI appeared to be linear and inversely proportional in both 2013 (R2 = 0.34, P = 0.58) and 2019 (R2 = 0.06, P = 0.25). Rising LST demonstrated significant effects on plants, with surface features playing a crucial role. The significance of this research is to understand that drought has an impact on agriculture, water resources and development. Remote sensing data monitor drought with high resolution over large areas and showed patterns in drought distribution during the study period in Niamey. This study could provide valuable insights into land and environmental planning in tropical regions.