Chen Yaning, Li Weihong, Deng Haijun, Fang Gonghuan, Li Zhi
State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Rep. 2016 Oct 20;6:35458. doi: 10.1038/srep35458.
The Tienshan Mountains, with its status as "water tower", is the main water source and ecological barrier in Central Asia. The rapid warming affected precipitation amounts and fraction as well as the original glacier/snowmelt water processes, thereby affecting the runoff and water storage. The ratio of snowfall to precipitation (S/P) experienced a downward trend, along with a shift from snow to rain. Spatially, the snow cover area in Middle Tienshan Mountains decreased significantly, while that in West Tienshan Mountains increased slightly. Approximately 97.52% of glaciers in the Tienshan Mountains showed a retreating trend, which was especially obvious in the North and East Tienshan Mountains. River runoff responds in a complex way to changes in climate and cryosphere. It appears that catchments with a higher fraction of glacierized area showed mainly increasing runoff trends, while river basins with less or no glacierization exhibited large variations in the observed runoff changes. The total water storage in the Tienshan Mountains also experienced a significant decreasing trend in Middle and East Tienshan Mountains, but a slight decreasing trend in West Tienshan Mountains, totally at an average rate of -3.72 mm/a. In future, water storage levels are expected to show deficits for the next half-century.
天山作为“水塔”，是中亚主要的水源地和生态屏障。快速变暖影响了降水量和降水类型以及原有的冰川/积雪融水过程，进而影响了径流和蓄水量。降雪量与降水量之比（S/P）呈下降趋势，同时降水类型由雪转雨。在空间上，天山中部的积雪面积显著减少，而天山西部的积雪面积略有增加。天山约97.52%的冰川呈现退缩趋势，在天山北部和东部尤为明显。河流径流对气候和冰冻圈变化的响应方式复杂。似乎冰川覆盖面积比例较高的集水区径流主要呈增加趋势，而冰川覆盖面积较小或无冰川覆盖的流域观测到的径流变化差异较大。天山中部和东部的总蓄水量也呈显著下降趋势，而天山西部呈轻微下降趋势，平均下降速率为-3.72毫米/年。未来，预计在接下来的半个世纪蓄水量将出现亏缺。
