Figure 1

Distribution map of permafrost in Northeast China and location of the study area, according to the degree of permafrost coverage, divided into continuous permafrost (> 90%), discontinuous permafrost (50–90%), sporadic permafrost (10–50%), isolated patches (0–10%); data from Jaroslav O. et al.³⁶, Arcgis10.2 https://developers.arcgis.com.