Permafrost Environment Dynamic Monitoring Around the Zonag Lake Using SAR Interferometry

The Zonag Lake burst in September 2011 and the water level decreased for many years after that. Part of the bottom of the lake was exposed after the bursting of Zonag Lake, in which the permafrost had formed due to the cold climate. Zonag Lake provides an ideal venue for observing the dynamic change and permafrost layer formation using InSAR. In this paper, SBAS-InSAR technology was used to monitor the surface deformation of Zonag Lake area with 106 Sentinel-1A images from 2017 to 2020. The backscattering, coherence and deformation have been jointly used to analyze the dynamic change of Zonag Lake. The experimental results show that the degraded area was undergoing differential ground deformation, the deformation is mainly uplift, with a velocity ranging from -78.3 to 72.8 mm/year. The distribution of the deformation shows spatial heterogeneity and uplift signal are mainly detected at the exposed bottom. Obvious seasonal deformation tread was detected, which is related to the freeze-thaw cycle of the active layer. Based on the annual deformation, the increased permafrost layer thickness (PLT) of the exposed bottom was retrieved, with the value ranges from 0 to 4.2 m. This work could provide valuable information for discussing the formation and evolution of permafrost.