Monitoring of surface deformation in a low coherence area using distributed scatterers InSAR: case study in the Xiaolangdi Basin of the Yellow River, China

摘要

The Xiaolangdi Basin of the Yellow River, located between Mengjin County and Jiyuan City in Henan Province, is composed of a reservoir, a barrage dam, flood discharge buildings, and a water diversion and power generation system, among which, the Xiaolangdi project is the only control project in the lower reaches of the Yellow River that has a large storage capacity. In this study, distributed scatterers InSAR (DS-InSAR) deformation analysis was used to process 27 images of ESA Sentinel-1A data for the period between September 10, 2018, and July 19, 2019. Using the generalized likelihood ratio test (GLRT) to select the statistical homogeneous pixels (SHP) and the eigenvalue decomposition method to optimize the interference phase, the time series surface deformation of the study area was obtained. The results showed that the maximum deformation rate in the study area was - 40.71 mm/year, the maximum deformation rate of the Xiaolangdi project was - 10.09 mm/year, and the larger deformation rates in the area around the Xiaolangdi Reservoir were mostly within the range - 35 to - 20 mm/year. Furthermore, small baseline subset (SBAS) InSAR and DS-InSAR are used for verification and analysis, and the monitoring results have high consistency. Therefore, to sum up, the time series deformation of low coherence areas may be monitored using DS-InSAR.