High-Resolution Detection of Periglacial Landforms Deformation Using Radarsat-2 and GF-7 Stereo Optical Imagery

Abstract

In cold mountain environments, rock glaciers and talus represent common periglacial landforms. Accurate monitoring of their activity is crucial for understanding alpine kinematics. Presently, spaceborne SAR satellites monitor periglacial landform deformations mainly utilizing medium-resolution data. However, capturing surface structure deformations accurately and comprehending the movement mechanisms remain challenging. This study employs high-resolution GF-7 optical stereo images and Radarsat-2 SAR data, introducing a multibaseline persistent scatterer and distributed scatterer combined multitemporal InSAR (MT-InSAR) method to identify rock glaciers and talus landforms, as well as to analyze their deformations. Initially, rock glaciers and talus are outlined using GF-7 optical images, and digital surface models are extracted. The developed MT-InSAR method then detects the line of sight and slope-parallel deformations of these landforms. Radarsat-2 monitoring reveals that 47.5% of identified rock glaciers are classified as active, while talus deformations are less active compared to rock glaciers. By utilizing high-resolution optical and SAR satellite data, we first documented the intricate deformation features within standard rock glaciers, such as the front, lateral margins, and optionally ridge-and-furrow deformations, as well as their interaction with the surrounding terrain topography. This discovery offers evidence of gravity-driven forces impacting rock glacier movement. We have also conducted a deformation analysis of the talus, obtaining spatial deformation characteristics of typical talus. It was observed that the deformation of the talus is jointly influenced by the conditions of surface debris cover and the slope of the terrain. This study highlights the value of high-resolution optical and SAR satellites in studying periglacial geomorphology dynamics.