A Permafrost Status Observed by ALOS-2 Interferometric Data in the Northern Qinghai-Tibet Plateau Between 2015–2020

As a global warning, the Qinghai-Tibet Plateau (QTP) permafrost is undergoing degradation, which can be a threat to the high-altitude infrastructure. Multitemporal interferometric synthetic aperture radar (MT-InSAR) is an effective tool to monitor freeze-thaw deformation cycles of permafrost. In this study, we employ small baseline synthetic aperture radar interferometry (SBAS) in the northern Qinghai-Tibet Railway (QTR), including Tuotuohe, Beiluhe, Wudaoliang and Xidatan regions with 73 scenes of L-band ALOS-2 stripmap SAR images between 2015 to 2020. The experimental results show that the maximum deformation of permafrost from Tuotuohe to Beiluhe area can reach -35 mm/year. Besides we combined optical data (GF-1, GF-2) found that the permafrost of some regions is undergoing degradation, which may cause thermal melting landslides. And our results can provide significant insight for monitoring permafrost deformation in QTP.