Mapping the permafrost stability on the Tibetan Plateau for 2005–2015

Abstract

Data scarcity is a major obstacle for high-resolution mapping of permafrost on the Tibetan Plateau (TP). This study produces a new permafrost stability distribution map for the 2010s (2005–2015) derived from the predicted mean annual ground temperature (MAGT) at a depth of zero annual amplitude (10–25 m) by integrating remotely sensed freezing degree-days and thawing degree-days, snow cover days, leaf area index, soil bulk density, high-accuracy soil moisture data, and in situ MAGT measurements from 237 boreholes on the TP by using an ensemble learning method that employs a support vector regression model based on distance-blocked resampled training data with 200 repetitions. Validation of the new permafrost map indicates that it is probably the most accurate of all currently available maps. This map shows that the total area of permafrost on the TP, excluding glaciers and lakes, is approximately 115.02 (105.47–129.59) ´ 104 km2. The areas corresponding to the very stable, stable, semi-stable, transitional, and unstable types are 0.86 ´ 104, 9.62 ´ 104, 38.45 ´ 104, 42.29 ´ 104, and 23.80 ´ 104 km2, respectively. This new map is of fundamental importance for engineering planning and design, ecosystem management, and evaluation of the permafrost change in the future on the TP as a baseline.