Temporal and Spatial Variation of Drought in Northwest Arid Region Based on Temperature Vegetation Drought Index
The northwest arid region has scarce rainfall and frequent droughts all year round,which seriously affects the local eco-logical balance,agricultural production and sustainable economic development.In order to clarify the spatiotemporal distribution charac-teristics of drought in the northwest arid region,based on the enhanced vegetation index(EVI)and land surface temperature(LST)was constructed to construct a temperature vegetation dryness index(TVDI)model to obtain the spatiotemporal variation characteristics of drought in the northwest arid region from June to September from 2000 to 2022,and the Sen+Mann-Kendall trend analysis method was used to clarify the drought trend,analyze the relationship between different land use types and drought.The results show these as follows.The spatial distribution of TVDI in the northwest arid region shows the characteristics of"low in the northwest and high in the southeast",with the average multi-year TVDI value of 0.67,which is at the level of medium drought.TVDI in the northwest arid region shows a trend of drought intensification,with an increase rate of 8.8 × 10-4 a-1,the significantly intensified area accounts for approximately 21.04％of the total area,and the slightly intensified area accounts for approximately 62.33％of the total area.TVDI values of unused land are high-er than other land types,and the higher the degree of drought,the higher The greater the contribution of unused land to TVDI.
万方数据
维普
