The area of high-elevation permafrost on the Tibetan Plateau (TP) ranks first in the world among middle- and low-latitude permafrost regions. The average temperature of permafrost on the TP is about -2 ℃, this warm permafrost is sensitive to climate change and human disturbance. Permafrost degradation has resulted in increased environmental and hazard risks. Therefore, mapping the permafrost on the TP is therefore of critical importance. 

Due to the harsh natural environment, the ground measurement data such as mean annual ground temperature (MAGT) at a depth of zero annual amplitude (10–25 m) in permafrost area of TP is very limited, which leads to the large uncertainty of permafrost map in this area. With the accumulation of ground observation data and remote sensing big data, it is possible to mapping the permafrost at TP with a high accuracy. 

Recently, RAN Youhua from Northwest Institute of Eco-Environment and Resources of Chinese Academy of Sciences (CAS), LI Xin from Institute of Tibetan Plateau Research of CAS, together with their collaborators collected and compiled the MAGT measurement data at 237 boreholes that widely distributed over the TP, and produced a new permafrost stability distribution map for the 2010s (2005-2015). 

Based on the predicted MAGT at a depth of zero annual amplitude (10–25 m) and the high altitude permafrost zonation system, the permafrost in TP was divided into very stable, stable, semi-stable, transitional, and unstable. In order to better describe the permafrost in the TP, a new permafrost zonation scheme is adopted in this new map. The high altitude permafrost zonation system is proposed by CAS Member CHENG Guodong.  

According to this new map, the total area of permafrost on the TP, excluding glaciers and lakes, is approximately 115.02×10⁴ 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 system based on MAGT is not only closely related to the permafrost thickness, the vertical connectivity and the development degree of periglacial landform, but also reflects the permafrost thermal stability which is very important in environment and engineering application. 

The new permafrost stability map is of fundamental importance for supporting engineering planning and design measures intended to reduce permafrost-related hazards and to enhance water resource management. It is also can be used to evaluate the permafrost change in the future on the Third pole as a baseline.  

The simulated MAGT and permafrost stability map in this study has been published onScience China Earth Sciences entitled as “Mapping the permafrost stability on the Tibetan Plateau for 2005-2015”.  

 Figure 1. Mean annual ground temperature (MAGT) on the Tibetan Plateau (Image by RAN Youhua) 

Figure 2. The permafrost thermal stability type map on the Tibetan Plateau. (Image by RAN Youhua) 

Contact:

RAN Youhua

E-mail: ranyh@lzb.ac.cn 

Address: Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China