Mass balance sensitivity to climate change: A case study of glacier No. 1 at urumqi riverhead, Tianshan Mountains, China

In this paper the degree-day mass balance model is applied to the sensitivity test of mass-balance/ELA (equilibrium line altitude) to climate change of Glacier No. 1 at Urumqi Riverhead, the Tianshan Mountains, China. The results demonstrate that the mass balance of Glacier No. 1, which is of continental type and accumulates in warm seasons, is less sensitive than that of a maritime glacier. On Glacier No. 1, air temperature rise of 1°C or precipitation increase by 20% can cause the ELA shift 81 m up or 31 m down respectively. Air temperature and precipitation play the different roles in the mass balance formation, in which the mass-balance hypsometry follows the temperature variations by the means of rotation against the elevation axis and it shifts in parallel with precipitation change. Assuming a future temperature rise of 2 °C the mass losing trend on Glacier No. 1 can not be radically alleviated even if there is a precipitation increase by 30%. This research was supported by the National Natural Science Foundation of China (No. 49571018), the Chinese Academy of Sciences (No. KZ951-B1-212), the National Key Project (No. 96-912-01-02), and the Special Grant for Cryospheric Research of Chinese Academy of Sciences.