The Distributive Characteristics of Frozen Ground in the East of Qinghai-Xizang Plateau
Wang Shading and Luo Xiangrui (Lanzhou Institute of Glaciology and Geocryology, Chinese Academy of Sciences) Guo Pengfei (906 Hydrogeological and Engineering Geological Brigade, Ministry of Geology and Minerals)
The investigated area is located in the eastern fringe of permafrost area of Qinghai-Xizang Plateau, developed predominantly continous permafrost, isolated permafrost and seasonal frozen ground. The permafrost underlies an area of about 144 000 km2 or 61 % of the investigated area. The distribution of the permafrost depends chiefly on the vertical zonation, while the latitudinal zonation and longitudinal zonation, are also revealed in some extent. Generally, the lower limit of permafrost will be risen 130 m with 1 °decrease of latitude. Because of the difference in precipitation, the lower limit of permafrost in western investigated area is higher than that in eastern. According to areal differences in the frozen ground distribution as well as geomorphological and climatic factors, four regions may be recognized: Isolated permafrost region in the northeast mountain ares, predominantly continous permafrost region in the Burehanbuda Shan and Anymaqen Shan, predominatly continous permafrost region in the Bayankela Shan and sporadic permafrost region in the southeast mountain area.