近期新疆哈密代表性冰川变化及对水资源影响

Changes of representative glaciers in Xinjiang Hami and their impact to water resources

新疆哈密是资源性缺水地区,冰川是该区主要的供给水源。为了对该区冰川和水文水资源的现状和未来变化做出合理评价和预估,以榆树沟6号冰川和庙尔沟冰帽为代表,结合野外实测资料以及近年来在冰川变化领域所取得的相关研究成果,综合分析了在气候变暖背景下新疆哈密地区冰川近年来的变化过程及对水资源的影响。结果表明,1972—2011年,榆树沟6号冰川厚度平均减薄20 m,减薄速率约为0.51 m/a,冰川末端退缩254 m,年均退缩约6.5 m。由于强烈消融,冰川表面径流发育明显,且在末端有冰碛湖形成。相比之下,庙尔沟冰帽消融速率相对较小,对气候变暖的敏感度较低,这与冰帽类型和所处海拔较高有直接关系。综合分析发现,流域有无冰川覆盖及覆盖的比率大小,直接造成哈密地区不同流域近期河川径流变化的差异。

Water scarcity is a big problem in Hami, Xinjiang and glaciers are the major water supply. In order to make reasonable evaluation and forecast of glaciers and water resources in Hami, taking Yushugou Glacier No. 6 and Miaoergou ice cap as representative, the study comprehensively analyzed the recent glacier changes in Hami and their impact on water resources under the background of climate warming based on in-situ observation and previous studies. Results indicated that the thickness of Yushugou Glacier No. 6 decreased by 20 m, or 0.51 m/a with the terminus retreat of 254 m, or 6.5 m/a during the period 1972--2011. Due to serious ablation, the surface meltwater runoff of Yushugou Glacier No. 6 was obvious and a moraine lake was formed at the terminus. By comparison, the melting rate of Miaoergou ice cap was smaller than Yushugou Glacier No. 6, which was directly related to the glacier types and the high altitude of Miaoergou ice cap with low sensitivity to climate warming. The comprehensive analysis found that the difference of recent runoff changes in various rivers was directly caused by whether there was any glacier coverage and its ratio in the drainage basins of Hami.