A GIS-aided response model of high-altitude permafrost to global change

Two models are used to simulate the high-altitude permafrost distribution on the Qinghai-Xizang Plateau. The two models are the "altitude model", a Gaussian distribution function used to describe the latitudinal zonation of permafrost based on the three-dimensional rules of high-altitude permafrost, and the "frost number model", a dimensionless ratio defined by manipulation of freezing and thawing degree-day sums. The results show that the "altitude model" can simulate the high-altitude permafrost distribution under present climate conditions accurately. Given the essential hypotheses and using the GCM scenarios from HADCM2, the "altitude model" is used for predicting the permafrost distribution change on the Qinghai-Xizang Plateau. The results show that the permafrost on the plateau will not change significantly during 20-50 a, the percentage of the total disappeared area will not be over 19%. However, by the year 2099, if the air temperature increases by an average of 2.91 degrees C on the plateau, the decrease in the area of permafrost will exceed 58%-almost all the permafrost in the southern plateau and in the eastern plateau will disappear.