Analysis and Prediction of Permafrost Changes in Qinghai-Xizang Plateau by CMIP6 Climate Models

Abstract

The model outputs from the sixth phase of the International Coupled Model Intercomparison Project （CMIP6） are used to diagnose the near-surface permafrost on the Qinghai-Xizang Plateau in this study.The models' ability to simulate climate variables related to permafrost and permafrost for the current period （1985 -2014） was assessed in comparison with observations and permafrost maps of the Qinghai-Xizang Plateau， and the multi-model ensemble averaging method was applied to predict the future trends of near-surface permafrost on the Plateau under four SSP scenarios for the periods 2021 -2040， 2041 -2060 and 2081 -2100.The results show that all CMIP6 models can simulate the distribution characteristics and trends of climate variables related to permafrost well， but， the simulation of air temperature has more obvious cold bias， and the simulation of snow is significantly larger.The current permafrost distribution calculated using the surface frost index （SFI） is in good agreement with the permafrost map of the Qinghai-Xizang Plateau， and the surface permafrost area from 1985 to 2014 is about 134.52×104 km2 （including the area of lakes and glaciers）.With increasing temperatures， the permafrost on the Tibetan Plateau shows a regional degradation trend in the 21st century.Under the SSP1-2.6， SSP2-4.5， SSP3-7.0， and SSP5-8.5 scenarios， permafrost in the eastern， southern and northern margins of the Qinghai-Xizang Plateau showed regional degradation.Between 2041 to 2060， the permafrost area decreases by 13.81×104 km2， 19.51×104 km2， 18.02×104 km2， and 24.84×104 km2， respectively， and by the end of the 21st century， the plateau permafrost is severely degraded on a large scale， with only 69.3%， 52.5%， 34.4%， and 26.3% of the current permafrost area remaining.

Keywords

• qinghai-xizang plateau
• cmip6
• surface frost index （sfi）
• permafrost
• projection