The spatial distribution of permafrost in the Qinghai-Tibet Plateau (QTP) is strongly controlled by local climatic topographic, geologic, and hydrologic factors, as well as surface conditions.
However, current studies and simulation models cannot be used to accurately estimate the permafrost distribution at the boundary regions, especially in the areas of the northern or southern permafrost limits.
Therefore, there is little sufficient data on the permafrost boundary regions to validate the models makes questionable of the simulation results in such areas. As a result, a field investigation of permafrost limit regions is essential for evaluation of the degradation and change of permafrost in the QTP.
Recently, scientists from Northwest Institute of Eco-Environment and Resources of Chinese Academy of Sciences mapped the distribution and variations of permafrost boundary and evaluate its degradation in the Xidatan region of the QTP, using ground penetrating radar (GPR) profiles with borehole drilling and thermal monitoring.
Results indicate the lowest elevation limit of permafrost occurrence is 4369 m above sea level in 2012, and the total area of permafrost in study area has been reduced by 13.8%.
Besides, results also show that not only global warming but also some non-climatic factors such as hydrologic processes and anthropic disturbances induce permafrost degradation and the rising of permafrost limit.
Scientists also show the northern permafrost boundary in the QTP may continue rising in the future if the air temperature continues to increase.
The primary goals of this study are to delineate the permafrost distribution in the northern boundary of the QTP, and evaluate changes in northern permafrost limit over the last four decades.
The study entitled “Variations in the northern permafrost boundary over the last four decades in the Xidatan region, Qinghai-Tibet Plateau” was published in Journal of Mountain Science.