近年来祁连山中段冰川变化

Change of Glaciers in the Central Qilian Mountain

基于遥感和实测的方法,对近50 a来祁连山中段,包括黑河流域和北大河流域的冰川变化特征进行了分析。研究表明:1956—2003年,祁连山中段所研究的910条冰川面积共缩小了21.7%。其中,黑河流域冰川面积缩小了29.6%,北大河流域冰川面积缩小了18.7%。小冰川面积变化较大冰川要大,其对气候变化的敏感性较强。由于祁连山中段东西跨度较大,气候和地形等因素的不同,直接造成了冰川变化的区域差异。近期野外考察发现,位于黑河上游的葫芦沟流域,1956—2010年冰川面积缩小了30.1%,近7 a冰川面积缩小的比率达到前期的近5倍,且其中的十一冰川由于消融严重,已经完全分离成2条独立的冰川。雪冰融水径流是该流域中重要的水源,在稳定河川径流、调节其年际变化和年内分配方面发挥着重要作用。

Change of glaciers in the central Qilian Mountain in recent 50 years,including the Heihe River Basin and the Beidahe River Basin,was analyzed based on the remote sensing data and field survey.Results indicated that the total area of 910 glaciers investigated was reduced by 21.7% with a reduction rate of 0.002 km2·a-1 during the period from 1956 to 2003,in which the total area of glaciers was reduced by 29.6% in the Heihe River Basin and 18.7% in the Beidahe River Basin.Reduction rate of the small glaciers was generally higher than that of the large ones,indicating that the small glaciers were more sensitive to climate change than the large ones.There was a regional difference in area change of glaciers due to the different geographical locations of the glaciers,local climate conditions and topographic factors in the central Qilian Mountain.Recent field survey revealed that the total area of glaciers in the Hulugou River Basin located in upper reaches of the Heihe River was reduced by 30.1% during the period from 1956 to 2010,and the reduction of glacier area in recent 7 years was 5 times of that in previous years.Shiyi Glacier located in this region was separated into two independent glaciers due to the serious ablation.Glacier melt runoff is the vital water source and plays an important role in stabilizing stream flow and regulating annual variation and distribution.