气候背景下冰川在博斯腾湖水量平衡中的作用

Effect of glaciers change to water balance of Lake Bosten under climatic backgrounds

基于博斯腾湖水量平衡关系,对博斯腾湖水量变化做了分析,认为博斯腾湖近年水位的显著变化与占其入湖水量85%的开都河流量变化有直接关系．冰川作为开都河上游重要的水资源形势,造就了开都河稳定的基流．部分冰川在近20年全球和区域气候变化影响下发生了较大退缩,消退的冰雪直接补给了开都河径流,对开都河连年丰水起了重要作用．随着相对海拔较低的中小冰川的退缩,冰益变薄雪线升高,冰雪储量减少,冰川对气温升高的敏感性开始降低,融水补给量可能随之减少,气候变暖所带来的融水补给效应将减弱,最终影响到博斯腾湖的入流补给．

According to the water-balance analysis carried out in Lake Bosten, discharge of Kaidu River tributary accounts for 85% of the lake＇s inflow, and thus plays a crucial role in the fluctuation of its water-level. Glaciers, as an important component of the water resources in the upper reach of Kaidu River valley, has had a considerable effect upon by the global and regional climate change of recent years. Water melted away from glaciers has channeled into the downstream section of the river and exceeds the base flow to have entered the Kaidu River over the past twenty years, during which time the lake keep a high inflow level. Small-sized glaciers are more sensitive to temperature rising. With the gradual diminishing and eventual disappearance of these small and middle scale glaciers situated in a fairly low-altitude location, the ELA （snow-line） will rise and the icecap will become thin. The volume and distribution area of the glacier will decrease, which will make the glacier less sensitive to climate change （in other words, preventing the glacier from melting to such a degree） , and bring less glacier-melt water discharge. As a result, the water-supply from melting glaciers that will flow into Lake Bosten will lessen.