Characterization and evaluation of permafrost thawing using GPR attributes in the Qinghai-Tibet Plateau

Recognizing the status of permafrost thawing and providing information for permafrost treatment in the Tibetan Plateau is a key problem. In this paper, a GPR experiment is designed to explore effective geophysical attributes for characterizing and evaluating the impact of key factors on permafrost thawing. A new algorithm for the assessment of rapid relative water content is also presented. After processing the GPR data, the weighted average frequency attribute, sweetness attribute and relative wave impedance attribute, which better characterize the effect of different factors on permafrost thawing, are selected. The weighted average frequency attribute can distinguish the thawing front and evaluate the extent of thawing in addition to the completely thawed fringe; the sweetness attribute can help to characterize thawing in water ice mixed with permafrost and evaluate the impact of free water on permafrost below the thawing front. The relative wave impedance attribute highlights the completely thawed fringe and other smaller internal stratifications in the permafrost thawing zone. Using the rapid relative water content assessment algorithm, it is easy to evaluate the extent of thawing using only GPR data. In addition, a thermokarst lake strengthens the degree of permafrost thawing. Permafrost thawing accelerates on sunny slopes. This study shows that roadbeds inhibit permafrost thawing and that a thermosyphon significantly inhibits permafrost thawing.