# Monitoring Water Area Dynamics in Kashgar (2003-2023) Using Multi-Source Remote Sensing Data
## 3 Results and Analysis
### Drivers of Water Body Area Change in the Kashgar Region
Evaptranspiration peaked in 2021 (2153.88 mm), diverging from the temperature peak, while the lowest value occurred in 2007 (1265.339 mm). Figure 13b illustrates the temporal trends of surface water area and mean annual evapotranspiration in the Kashgar region from 2003 to 2023. A discernible downward trend in surface water area contrasted with an upward trend in evapotranspiration, indicating largely inconsistent patterns. Further analysis revealed a negative correlation between surface water area and mean annual temperature (correlation coefficient = 0.0631), as shown in Figure 13c. This suggests that evapotranspiration may act as an indirect driver of surface water area changes. Figure 11: (**a**) Spatial distribution of precipitation in Kashgar, (**b**) temporal trend of average annual precipitation in Kashgar (2003–2023), (**c**) temporal covariation of water body area and precipitation in Kashgar (2003–2023), (**d**) correlation between water body area change and annual precipitation in Kashgar (2003–2023). The source of surface water recharge in Kashgar remains a subject of ongoing debate within the scientific community, with no definitive consensus reached. This study aims to elucidate the relationship between surface water recharge in Kashgar and regional climate change by investigating the correlation between changes in Kashgar's water area and climatic factors in its surrounding regions. This analysis seeks to provide a scientific foundation for a deeper understanding of the region's hydrological cycle characteristics. Given Kashgar's topography, which is characterized by higher elevations in the southwest and lower elevations in the northeast, with most rivers and lakes originating from the southwestern mountainous areas and distributed along the slopes, this study selected annual average precipitation data from Taxkorgan County and Yecheng County, located in Kashgar's southwestern mountainous region. The objective is to analyze the potential relationship between the trends in these climatic variables and changes in Kashgar's water area. Figure 14a reveals a statistically significant positive correlation between changes in Kashgar's surface water area and the average annual precipitation in Taxkorgan County (R\({}^{2}\) = 0.5687, \(p\) = 2.4 \(\times\) 10\({}^{-33}\) < 0.05). This strong correlation indicates that precipitation in Taxkorgan County is a significant driver of surface water area fluctuations in Kashgar. Similarly, Figure 14b demonstrates a significant positive correlation between changes in Kashgar's surface water area and average annual precipitation in Yecheng County (R\({}^{2}\) = 0.5461, \(p\) = 1.2 \(\times\) 10\({}^{-33}\) < 0.05). This finding further supports the conclusion that precipitation in Yecheng County plays a crucial role in influencing surface water dynamics in Kashgar. This study also investigated the relationship between changes in Kashgar's water area and average annual temperature and evaporation in Taxkorgan and Yecheng County. Figure 12: (**a**) Spatial distribution of temperature in Kashgar, (**b**) temporal trend of average annual temperature in Kashgar (2003–2023), (**c**) temporal covariation of water body area and temperature in Kashgar (2003–2023), (**d**) correlation between water body area change and annual temperature in Kashgar (2003–2023). Counties. However, these analyses did not reveal statistically significant correlations (\(p>0.05\)), suggesting that temperature and evaporation in these surrounding areas are not primary drivers of surface water area fluctuations in Kashgar. In contrast, precipitation in the surrounding areas emerged as the key factor influencing changes in Kashgar's water area. Figure 14: (**a**) Correlation between changes in Kashgar’s water area (2003–2023) and average annual precipitation in Taxkorgan County, (**b**) correlation between changes in Kashgar’s water area (2003–2023) and average annual precipitation in Yecheng County.