Responses of active layer thickness on the Qinghai-Tibet Plateau to climate change
XU Xiaoming;WU Qingbai;ZHANG Zhongqiong;State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences;University of Chinese Academy of Sciences;
The change of active layer thickness has significant influence on the ecosystem,energy balance and carbon cycle between ground and atmosphere,therfore Stefan formula was used to simulate the distribution and spatial variation of active layer thickness on the Qinghai-Tibet Plateau from 1981 to 2010. It is found that the active layer thickness is 2. 39 m in average in permafrost regions,which is the smallest in Qiangtang Basin and the largest in the marginal zones of permafrost regions. Active layer thickness is larger in the Qilian Mountains,the West Kunlun Mountains and the Nyainqentanglha Mountains. Owing to climate change,active layer thickness on the plateau has an increasing tendency; during the 30 years from 1981 to 2010,the active layer thickness had changed from-1. 54 to 2. 24 m,with a change rate of-5. 90 to 10. 13 cm·a~(-1) and an average rate of1. 29 cm·a~(-1). The change of active layer thickness is basically consistent with the change of mean annual air temperature,which indicate that climate change has a great impact on the active layer thickness.