Properties of ground surface temperature within the Engineering Corridor traversing the Xing'an permafrost region in Northern Northeast China

Abstract

Permafrost degradation emerges as a critical threat to sustainable infrastructure development in cold regions. Engineering activities across Northern Northeast China have been shown to modify ground surface temperature (GST), thereby profoundly altering the thermal stability of underlying permafrost layers. To this end, GSTs at different latitudes were investigated at sites along the Engineering Corridor covering the National Highway from Jiagedaqi to Mohe and China-Russia crude oil pipelines. Electrical resistivity tomography was also conducted to examine permafrost distribution and influencing factors. Results indicated that adverse snows on the surface facilitated higher GSTs associated with frost numbers less than 0.5, further accelerating Xing'an permafrost degradation. The insulation provided by snow layers contributed to progressively warmer temperatures at northern latitudes, enhancing the mean annual GST from 2.28 °C to 7.08 °C and advancing the timing of the coldest temperatures. Heat absorption in the gravel land in summer and heat preservation by snow cover in winter promoted the talik in the ambient topsoil and surrounding pipelines. Snowfall intensified the surface offset, with the highest recorded in January (25.1 °C) and the lowest in April (2.2 °C) in gravel lands, consistently demonstrating a positive monthly difference. Additionally, accumulated water significantly increased the thawing depth and lowered the load-bearing capacity in slopes, further triggering cracks and tilting. These findings indicated that long-term monitoring should be carried out to determine the spatiotemporal variations of GST for validating complex permafrost distribution and facilitating a better understanding of infrastructure-induced permafrost response and consequent degradation.