Changes of Ice-thickness and Volume for Representative Glaciers in Tianshan Mountains in the Past 50 Years

Changes of glacier volume is directly related to glacial water resources and contribution of glacier changes to river runoff. With the support of GPR-3S technology, this paper studied ice-thickness and volume changes of the four typical glaciers in the three areas of Tianshan Mountains in recent years based on radar survey data, high-resolution remote sensing image, topographic maps and observation data. Furthermore, a comparison was made between the changes of these glaciers and the possible causes for the differences were analyzed. Results indicated that Urumqi Glacier No.1 underwent thinning of 0.15 m a -1 with the ice-volume loss of 26.2 × 10 6 m 3 and retreated by 3.8 m a -1 during 1962-2006. During 1986-2009, the ice tongue of Heigou Glacier No.8 on the south slope of Mt. Bogda thinned by 0.57 m a -1 , corresponding to the loss in ice-volume of 25.5×10 6 m 3 . At the same time, the terminus retreated by 11.0 m a -1 . The ice-thickness of Glacier No.4 of Sigong River located on the north slope of Mt. Bogda decreased to 0.32 m a -1 with an ice-volume loss of 14.0×10 6 m 3 over the period 1962-2009. The glacier terminus retreated by 11.0 m a -1 in the same period. For Qingbingtan Glacier No.72 in the Tomor region, the ice tongue thinned by 0.22 m a -1 , corresponding to a loss of ice-volume of 14.1 × 10 6 m 3 during 1964-2008. The glacier terminus retreated by 40.0 m a -1 in the same period. Results indicated that Qingbingtan Glacier No.72 retreated most intensively, followed by Heigou Glacier No.8, which differed slightly from Urumqi Glacier No.1 and Keqikaer Glacier. However, its changing magnitude was slightly larger than that of Glacier No.4 of Sigong River and Hami Miaoergou Glacier, indicating that such differences were directly influenced by regional climate change and physical features of glaciers.