Time-Series InSAR Technology for Ascending and Descending Orbital Images to Monitor Surface Deformation of the Metro Network in Chengdu

Abstract

Over the past decade, Chengdu has become one of the fastest growing urban centers in China. However, the massive expansion of the infrastructure and the transportation network has resulted in surface subsidence which typically presents as a hard to detect geological hazard. As an all-day, all-weather, high-precision, and wide-range surface deformation monitoring tool, interferometric synthetic aperture radar (InSAR) technology has unique advantages with respect to monitoring long-period surface subsidence. In this article, the Sentinel satellite data from March 2018 to March 2021 for the ascending and descending orbits are used to obtain the deformation fields of Chengdu's surface in two different satellite line of sight directions using the time-series InSAR technique. The results are then used to invert the surface deformation field in the vertical direction and analyze it via the Peck and Logistic models. In addition, wavelet transform technology was used to investigate the relationship between deformation and climate. The results show that the surface deformation in Chengdu is stable, and the rate of deformation in the center of the urban area is within 5 mm/year. The main reason for the emergence of ground settlement funnels is the construction of subways and real estate development. It was also observed that the deformation of the buildings shows a clear periodic pattern, which is closely related to the seasonal rainfall and temperature in Chengdu.

Keywords

• Chengdu
• logistic model
• peck model
• surface deformation
• time-series interferometric synthetic aperture radar (InSAR)
• wavelet transform (WT)