Comparison of changes in glacier area and thickness on the northern and southern slopes of Mt. Bogda, eastern Tianshan Mountains

Rapid shrinkage and dramatic volume loss of the glaciers on Mt. Bogda in the eastern Tianshan Mountains have resulted in water shortages in the surrounding arid regions of China. Understanding ice thickness and its variation is important to the analysis of changes in glacial volume, which are directly related to regional hydrology and water resources. Fan-shaped Diffluence Glacier and Heigou Glacier No. 8 are located on the northern and southern slopes of Mt. Bogda, respectively. In this paper, the spatial distribution of the ice thickness of these two glaciers and the changes in their area and volume are discussed based on a 2009 survey result and comparison to previous investigations. The mean ice thickness of the tongue of Fan-shaped Diffluence Glacier was about 82.3 m and the calculated ice volume was 385.2 × 106 m3 in 2009. It had thinned by 14 ± 8 m (0.30 ± 0.17 m a− 1) from 1962 to 2009, equivalent to an ice volume loss of 65.5 ± 37.4 × 106 m3. The mean ice thickness of the tongue of Heigou Glacier No. 8 was 58.7 m and the calculated ice volume was 115.1 × 106 m3 in 2009. The tongue of Heigou Glacier No. 8 thinned by 13 ± 6 m (0.57 ± 0.26 m a− 1) from 1986 to 2009, which corresponds to an ice volume loss of 25.5 ± 11.8 × 106 m3. The greater thinning and retreat of Heigou Glacier No. 8 than those of Fan-shaped Diffluence Glacier is partially due to topographic characteristics. The difference can be attributed mainly to the greater increase in temperature on the southern slope than on the northern slope.