The drought monitoring cased on TVDI model: A case study of Luxi, Yunnan Province, Southwestern China

Abstract

Drought is a very complex natural disaster caused by regional water budget or imbalance between supply and demand. Due to the unique geographical environment and climate characteristics, Yunnan plateau always break the drought disasters. Monitoring is the key to simulating, warning, pretecting and reducting the disaster. In this study, the Ts-NDVI feature of Luxi County was established by the data of normalized vegetation index (NDVI) and temperature of land surface (Ts) based on the Landsat 8. Meanwhile, based on the resluts of space feature, temperature vegetation drought index (TVDI) calculated as an index parameter. Furtheremore, combined with the information of meteorology and the DEM data of land using types, the drought conditions were verified. The results show that: (1) As a widely recognized drought index, the TVDI is highly feasible to monitor the drought situation in Luxi County; (2) The results of Ts- NDVI and TVDI are shown by using remote sensing image data in the study area in 2013 and 2018. Using Landsat 8 remote sensing image data in 2013 and 2018 to calculate and construct Ts-NDVI feature and TVDI, the results show that the study can be divided into five drought grades: wet, normal, light drought, drought and heavy drought; (3) As time goes on, the drought has been reduced from 2013 to 2018; The proportion of severe drought declined during the study period, especially in the central and northern areas of the county. Except for the continuing severe drought in the southern region, the rest of the region has been alleviated. Normal and light drought increased greatly, mostly in the northern region, and wet areas mostly in the central region.