Detection of permafrost sensitivity of the Qinghai–Tibet railway using satellite radar interferometry

Abstract

Climate change and human involvement are changing the dynamics of permafrost environments, with potential impact on the safety and stability of infrastructure. The Qinghai–Tibet Railway (QTR) has been designed to withstand the dynamic permafrost conditions. Yet, in situ measurements of the track stability at elevations of about 5 km are scarce. Here we investigate whether satellite radar interferometry can be used to detect indications of permafrost-related instabilities over an 80 km segment at the highest part of the QTR. An analysis method using all available pixels over the track is developed and implemented. We find inhomogeneous deformation along the track, with vertical rates of up to 10 mm year−1. We also find seasonal displacements over a range of 15 mm. We conclude that the satellite time series are able to detect variability with characteristics similar as expected from permafrost dynamics. While the signal cannot be unambiguously attributed to permafrost, the approach demonstrates the value of continuous satellite observations for the operational safety of the QTR.