## 4 Results of the Experiment
### Analysis of Spatial Variability in Drought
#### 4.3.1 Monthly-by-Month Drought Changes in Vegetation in Laibin City
By March, the central and eastern parts of the vegetation area encountered moderate drought, covering 25.57% of the region, with most areas experiencing light drought and no drought in the eastern part of the city. In April, drought conditions worsened on a small scale, progressing from moderate to severe drought in the central and eastern parts. By May, the drought began to alleviate, particularly in the eastern region, which showed signs of relative wetness. However, in June, the drought intensified significantly, leading to a large area experiencing severe drought, reaching the highest percentage in the past three years. July saw a slight relief in drought conditions compared to June, with most areas in the vegetation zone facing light drought (64.79% of the area), while moderate drought was concentrated in the central  
Figure 8: Month-by-month drought level results of vegetation in Laibin in 2021.  
and eastern parts, covering 25.47% of the region. By November, half of the area experienced drought conditions of medium drought level or higher, with severe drought affecting a larger area, accounting for 30.62% of the region. In December, there was a significant alleviation of drought conditions, with the eastern region no longer facing drought and wet areas emerging. Figure 10 shows the monthly drought level results of Laibin City in 2022. Figure 11 illustrates the fluctuation in the ratio of drought-affected areas in Laibin City throughout 2022. In 2023, there was no significant drought in January, and the vegetation area of Laibin City remained normal and locally wet. The drought worsened in February, with most of the area experiencing moderate drought. In March, the drought eased, with large areas of light drought in the eastern part of the city. In April, the situation worsened, with light drought prevailing, and moderate drought in the central, east-central, and northwestern parts of the city, accounting for 39.54% of the area. In May, the drought continued to worsen, transitioning from medium drought in April to severe drought in most areas of the vegetation in Laibin City, with medium drought covering 68.66% of the total area. The drought persisted in June, July, August, and September, mainly as medium drought. The largest area of severe drought was recorded in June, covering 30.04% of the area. In August, the largest area of medium drought was observed, also covering 30.04% of the area. The most extensive moderate drought area was recorded in August, accounting for 78.27% of the area. In October, the drought significantly eased, while in November, light drought dominated. In December, the drought intensified, with moderate drought prevailing, covering 73.12% of the area. Notably, in the last three years, only in 2023, there was a significant drought in December in the vegetation area of Laibin City. Figure 12 shows the monthly drought level results of Laibin City in 2023. Figure 13 illustrates the change in the proportion of the drought area in Laibin City in 2023. Figure 11: Map of changes in the percentage of drought area of vegetation in Laibin by month in 2022. Figure 12: Month-by-month drought level results of vegetation in Laibin in 2023.