Wind erosion caused by the change of Chaiwopu lake on the northern foothill of Tianshan Mountain, based on SBAS-InSAR

Abstract

In arid regions, terminal lakes play a crucial role in maintaining the local ecological environment. However, due to the impact of climate change and human activities, terminal lakes are prone to shrinkage and drying up. The exposed lakebeds became new sources of sand and dust, leading to severe land degradation. This study extracted the water surface area of the Chaiwopu Lake in Urumqi and calculated the fractional vegetation cover (FVC) in the surrounding areas based on Landsat images from 2000 to 2022. The changes in FVC and lake area before and after the implementation of the policies on fallow and groundwater extraction restriction in 2014 were analyzed. Using the SBAS-InSAR method, the surface deformation during the period of minimum lake area from 2014 to 2018 was estimated, and the process of wind erosion and accumulation in the dried lake basin was analyzed. The results showed that from 2011 to 2014, Chaiwopu Lake experienced rapid shrinkage, and the lake almost disappeared. After 2014, the lake rapidly recovered, reaching 70% of its original area by 2021. With the recovery of the lake, the vegetation coverage in the surrounding area has changed from decreasing to increasing. During the period of lake shrinkage, the dried lake basin experienced severe wind erosion, with the maximum erosion rate exceeding 40 mm/year. The sand and dust from the dried lake basin accumulated around the lake under the influence of wind, further accelerating land degradation in the surrounding areas. After 2021, the restored lake and wetland surface covered the once-dry lake basin again, and the largest dust source in the region nearly disappeared. The study results indicated that the restoration of the lake and surrounding vegetation can eliminate the sources of sand and dust and prevent their transportation, effectively preventing land desertification.