Koxkar [Candidate]
Integrated CryoNet Cluster Information

The Koxkar Site is a specialized field site focus on the physical processes of large valley glaciers in Central Asia. The site is located in western Tien Shan, China where many large dendritic valley glaciers are developed with outstanding characteristics, such as extensive supraglacial debris cover, narrow accumulation area, thermal karst structure, etc. These large glaciers, with small numbers in the regional glacier family, occupy over 81% of the total ice mass and control the dynamics of the glacier storage and meltwater resources in the region, and thus, is of great importance to the developments of the downstream societies.

The Koxkar Glacier is a representative of such valley glacier under surveillance of the Koxkar site. It originats from Mt. Koxkar (6342 m a.s.l.) and flows southeast to the terminus of 3020 m a.s.l. The glacier extends 25.1 km in length and covers an area of 73.2 km². The equilibrium line occurs at 4300 m a.s.l. in the icefall from whose foot a 15.5-km-long, debris-mantled glacier tongue appears. The supraglacial debris covers an area of about 20.8 km², which accounts for 68.2% of the total ablation area. The thicknesses of debris layer range from less than 0.01 m on the upper reach of the ablation area and on ice-cliff faces to more than 3.0 m near the glacier snout (Figure 2). The Koxkar glacier catchment covers an area of 116.5 km², out of which glacierized area, rock slope and grassland account for 62.8%, 33.9% and 3.3%, respectively.The mean annual air temperature observed near the terminus of the glacier is 0.30 ºC, whilst the mean summer temperature is 8.62 ºC. The melt season over the Koxkar glacier starts in late-April and continues for six months until late-October. Mean annual precipitation near the terminus is ~ 524 mm, of which > 80% occur during the melting period (Han et al. 2008). The mean runoff measured near the snout is ~102.86 × 106 m3 a-1, of which 93.6% occur during the ablation season.

Short term measurements on meteorology, glacial runoff and mass budget were carried out during June 2003 and August 2006, aiming at deriving relevant glacier natures to evaluate the meltwater runoff. Since April 2007, however, systemetic observations on glacier and meltwater variations were performed and three observational stations were established to provide continuous records of meteorological and hydrological data.

Han Haidong, Ding Yongjian, Liu Shiyin, Wang Jian. 2015. Regimes of runoff components on the debris-covered Koxkar glacier in western China. Journal of Mountain Science, 12(2): 313-329.

Han Haidong. 2013. AIWA 1.0: A universal graphical user interface for distributed hydrological modeling. Computers & Geosciences, 59: 108-115.

Han Haidong, Liu Shiyin, Wang Jian, Wang Qiang, Xie Changwei. 2010. Glacial runoff characteristics of the Koxkar glacier, Tuomuer-Khan Tengri Mountain Ranges, China. Environmental Earth Sciences, 61(4)?665-674.

Han Haidong, Wang Jian, Wei Junfeng, Liu Shiyin. 2010. Backwasting rate on debris-covered Koxkar Glacier, Mt. Tuomuer, China. Journal of Glaciology, 56(196)?287-296.

Han Haidong, Ding Yongjian, Liu Shiyin.2006. A simple model to estimate ice ablation under a thick debris layer. Journal of Glaciology, 52(179)?528-536.