Exploring the Evolution of Permafrost on the Tibetan Plateau (1979-2100) Using the TTOP Model

The permafrost in the Tibetan Plateau is extremely sensitive to the response of climate warming. Predicting the evolution of permafrost in the Tibetan Plateau in the future can provide a reference for future engineering construction and resource management in the Tibetan Plateau. In this study, the random forest regression model and the temperature at the top of permafrost (TTOP) model are combined, the random forest regression model is used to simulate the long-term series of land surface temperature, the multiple climate model data in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and TTOP model are used to simulate the history (1979-2018) and predict the future (2019-2100) the distribution of permafrost in the Tibetan Plateau. The results show that since 1979, due to climate warming, more than 20% of the permafrost in the Tibetan Plateau has disappeared. Under the four Shared Socioeconomic Pathways (SSPs): SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, permafrost will degrade at different rates. The degradation rate under SSP1-2.6 is the slowest, and about 20.1 % of the permafrost will disappear by 2100. The degradation rate under the SSP5-8.5 is the fastest, and about 82.4 % of the permafrost will disappear by 2100. Under the SSP2-4.5 and SSP3-7.0, 37.57 % and 69.1 % of the permafrost will disappear by 2100, respectively. The above results can provide a reference for engineering construction in the Tibetan Plateau.