Variations in equilibrium line altitude of the Qiyi Glacier, Qilian Mountains, over the past 50 years

Based on observations of the equilibrium line altitude (ELA) of the Qiyi Glacier in the Qilian Mountain, we established a statistical model between ELA and its major influencing factors, warm season air temperature (air temperature averages for September, July and August) and cold season precipitation (total precipitation in the period January through March). Warm season air temperature was the leading climatic factor influencing ELA variations. The glacier ELA ascends (descends) 172 m when warm season air temperature increases (decreases) by 1A degrees C, and ascends (descends) 62 m when cold season precipitation decreases (increases) by 10%. In the period 1958-2008, the glacier ELA showed a general increasing trend, ascending 230 m and reaching its highest altitude in 2006 at 5131 m a.s.l., close to the glacier summit. If future climate is similar to that in the period 2001-2008, the Qiyi Glacier will not stabilize until it retreats by 2.08 km.