Permafrost Warming in the Context of Step-wise Climate Change in the Tien Shan Mountains, China

摘要

The Tien Shan Mountains, the largest mountain range in the Xinjiang Autonomous Region of north-western China, significantly influence the climate of central Asia. Recent permafrost changes in the region of the headwaters of the Urumqi River, as well as its relationship to climatic factors, were studied based on ground temperatures measured in a 60 m deep borehole, air temperatures and precipitation over a period from 1992 to 2011. The results showed that the maximum active-layer thickness (ALT; 1.70 m) occurred in 2009 and 2011, with an increase of 0.45 m compared with 1992. The change in ALT was related to the variation in the climatic conditions, and the increase in the deep-seated permafrost temperature. The permafrost temperature increased from -1.7 degrees C in 1992 to -1.1 degrees C in 2011, and the permafrost base moved upwards by approximately 14 m from 1992 to 2011. The long-term step-wise change in the air temperature may be the main cause of the permafrost warming in the headwaters of the Urumqi River. Copyright (c) 2015 John Wiley & Sons, Ltd.