## 3 Results
### Analysis of Future Continuing Trends in TVDI in MUSL  
As shown in Figure 8, the Hurst exponent of the four seasons and the whole year in the MUSL ranged from 0.16 (summer) to 0.92 (winter). The averages for summer, fall, and winter were 0.45, 0.57, and 0.56, respectively, indicating that summer was mainly characterized by anti-persistence, while autumn and winter exhibited positive persistence. TVDI time series in spring and throughout the year appear close to white noise, suggesting that temporal and geographical changes in drought during spring and the entire year are largely random. The lowest value (0.36 in summer) and the highest value (0.73 in autumn and the whole year) of the Hurst exponent are both located in Yanchi County. This can be attributed to the area's location within the agro-pastoral ecotone, where increased  
Figure 7: (**a**) Types of trends in drought changes and (**b**) trends in the significance for various utilizing land categories in MUSL (2001–2020). (**T**) The whole year; (**S**p) spring; (**Su**) summer; (**A**) autumn; (**W**) winter.  
agricultural irrigation during summer, coupled with high temperatures leading to heightened vegetation evapotranspiration and inadequate precipitation, results in decreased soil moisture content and deteriorating vegetation development, thus exhibiting poor drought persistence. Conversely, the warm and humid climate in autumn facilitates vegetation recovery, leading to sustainable drought persistence. The Hurst exponent values for each land use type are concentrated above 0.51 in autumn and winter. Autumn and winter exhibit a significantly higher number of pixels with favorable relationships compared to spring and summer, with the proportion of pixels displaying negative relationships in autumn being less than 20%, significantly lower than the other three seasons and the entire year. The percentage of pixels for all land types with a Hurst exponent greater than 0.6 shows a pattern of increase, decrease, and subsequent increase from summer to winter, peaking in fall, indicating a progression from a small to a large percentage of strong positive, persistent pixels: autumn > winter > spring > summer. Forest grassland and unused land exhibit reverse persistence throughout the year, spring, and summer, while the proportion of pixels with Hurst exponent greater than 0.6 for cropland and building land in the entire year exceeds 36%.  
To establish its inter-annual and seasonal change trend distribution of future drought in MUSL, the Hurst exponent is combined with a slope spatial change pattern mapping (Figure 9a). Annual and seasonal TVDI in MUSL are expected to mostly transition from dry to wet conditions and continual drying, with drought alleviation concentrated in central Ordos and Shenmu City. The springtime transition zone, primarily occurring in the middle of Otog Banner, Otog Front Banner, along with the surrounding counties of Dingbian and Jingbian, constitutes 54.39% of the whole; regional drought is projected to improve by 72.13% in summer, with fall and winter showing similar trends except for persistent wetting in the southeast for Yanchi District and the southern portion of Dingbian District.  
Figure 8: (**a**) Spatial Hurstexponentin different seasons and (**b**) percentage of Hurst exponentpixels for different land use types in MUSL (2001–2020). (T) The whole year; (Sp) spring; (Su) summer; (A) autumn; (W) winter.