General Survey of Large-scale Land Subsidence by GACOS-Corrected InSAR Stacking: Case Study in North China Plain

摘要

Satellite-based InSAR (Interferometric Synthetic ApertureRadar) provides an effective way to measure large-scale land surfacemotions. Currently, the atmospheric phase delay is one of the most criticalissues in InSAR deformation monitoring. Generic Atmospheric CorrectionOnline Service (GACOS) is a free, globally available and easy-to-implementtool to generate high-resolution zenith total delay maps, which could beused for InSAR atmospheric delay correction. The mean velocity could then beestimated by stacking multiple GACOS-corrected interferograms. We appliedthe proposed GACOS-corrected InSAR stacking method in the North China Plainand analysed its performance. Within the 549 interferograms, more than85 % gained positive correction performances. The correlation between thephase-dZTD indicator and the performance reached 0.89, demonstrating asignificant relationship. Deformation maps revealed by InSAR stacking withand without GACOS corrections showed that GACOS could mainly remove thetopography-related and long wavelength signals.