Research on the temporal and spatial variation characteristics of drought in the Hexi Corridor region based on TVDI

This study is based on Landsat 8 data from 2013 to 2023. By fitting Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) data, we constructed the NDVI-LST feature space to obtain Temperature-Vegetation Drought Index (TVDI) data for the Hexi Corridor region over the 11-year period. We analyzed the temporal and spatial distribution evolution characteristics of drought in the Hexi Corridor and explored future evolution trends using the TheilSen Median trend analysis method and the Mann-Kendall test. The results indicate that:(1) From 2013 to 2023, the average TVDI in the Hexi Corridor region was 0.61, indicating an overall moderate drought level. (2) The annual average TVDI values exhibited significant fluctuations and a slow-increasing trend, showing a gradual intensification of drought phenomena. (3) In 87.63% of the area, future land drought conditions remain stable; 6.94% of the area is becoming progressively drier, while 5.43% is becoming increasingly wet.