Ground surface deformation in permafrost region on the Qinghai-Tibet Plateau: A review

Ground surface vertical deformation in permafrost regions encompasses seasonal fluctuations in hydrothermal properties within the active layer and the long-term ground ice change near the permafrost table, serving as a crucial “window” for permafrost observation. This review summarizes research progress regarding deformation in the permafrost region on the Qinghai-Tibet Plateau (QTP), highlighting methods for acquiring deformation data, spatiotemporal characteristics, and its link with permafrost dynamics. Published results indicate that the seasonal deformation amplitude in the QTP's permafrost regions ranges from 0 to 120 mm, with regional means of 3.1–19 mm. The long-term deformation trend ranges from −65.9 to 74.6 mm/a, with an average subsidence value of 1.1 to 13 mm/a. The long-term subsidence rate of the QTP exhibits an increasing trend, closely related to permafrost thermal conditions and ground ice melting near the permafrost table. Variations in hydrothermal characteristics within the active layer, ground ice content, mean annual ground temperature and the different land cover types contribute to spatiotemporal differences in deformation over permafrost terrain. Previous research indicates that the deformation in permafrost regions provides valuable insights into active layer thickness, soil moisture dynamics, freeze-thaw processes, ground ice melting, and permafrost boundary delineation. However, the lack of accurate data and understanding of the process mechanism have brought challenges to obtaining permafrost change information based on deformation. Future research endeavors should prioritize enhancing the accuracy of deformation monitoring and deeper understanding the mechanisms linking permafrost internal hydrothermal dynamics and deformation.