近50年来祁连山冰川变化——基于中国第一、二次冰川编目数据

Glacier changes in the Qilian Mountains in the past half century:Based on the revised First and Second Chinese Glacier Inventory

基于修订后的祁连山区第一次冰川编目（1956-1983年）和最新发布的第二次冰川编目数据（2005-2010年）,对祁连山区冰川变化进行分析。结果表明：①祁连山区现有冰川2684条,面积1597.81±70.30 km^2,冰储量约84.48 km^3。其中,甘肃省和青海省各有冰川1492条和1192条,面积分别为760.96 km^2和836.85 km^2。②祁连山区冰川数量和面积分别以面积〈1.0 km^2的冰川和面积介于1~5 km^2的冰川为主;冰川平均中值面积海拔为4972.7 m,并自东向西由4483.8 m逐渐上升为5234.1 m。③疏勒河流域冰川面积和冰储量最大,占祁连山冰川总量的31.91%和35.11%;其次是哈尔腾河流域,巴音郭勒河流域冰川面积最小,为2.20 km^2;黑河流域是祁连山区冰川平均面积最小的四级流域,冰川平均面积仅0.21 km^2。④近50年间祁连山冰川面积和冰储量分别减少420.81 km^2（-20.88%）和21.63 km^3（-20.26%）。面积〈1.0 km^2的冰川急剧萎缩是该区冰川面积减少的主要原因,海拔4000 m以下山区冰川已完全消失,海拔4350~5100 m区间冰川面积减少量占冰川面积总损失的84.24%。冰川数量和面积在各个朝向均呈减少态势,其中朝北冰川面积减少最多,朝东冰川面积减少最快,而西北朝向冰川变化最为缓慢。⑤祁连山冰川变化呈现明显的经度地带性分异,东段冰川退缩较快,中西段冰川面积减少较慢。

According to the Second Chinese Glacier Inventory （SCGI） that were mostly compiled based on Landsat TM/ETM＋images, the Qilian Mountains contained 2684 glaciers covering an area of 1597.81d：70.30 km^2 and ice volume of-84.48 krn3 from 2005 to 2010. While most glaciers are small （85.66% are smaller than 1.0 km^2）, some larger ones （12.74%, with each having 1.0 and 5.0 km^2） cover 42.44% of the total glacier area. The Laohugou No. 12 Glacier （20.42 km^2） located on the north slope of the Daxue Range is the only one larger than 20 km^2 in the Qilian Mountains. The average median altitude of glacier was 4972.7 m a.s.1, and gradually rose from east to west. Glaciers in the Qilian Mountains are mostly distributed in Gansu and Qinghai provinces, which have 1492 glaciers （760.96 km^2） and 1192 glaciers （836.85 km^2）, respectively. In 11 watersheds, the Shule River contains most of the glaciers in either area or volume. However, the Heihe River, the second longest interior river in China, has the minimum average area of glacier. Comparison of glaciers from the SCGI and the revised glacier inventory based on topographic maps and aerial photos taken from 1956 to 1983 indicated that all the glaciers in the Qilian Mountains were receding, which is consistent with other mountains and plateaus in western China. In the past half century, the area and volume of glaciers decreased by 420.81 km^2 （-20.88%） and 21.63 km^3 （-20.26%）, respectively. The glaciers which are smaller than 1.0 km^2 constituted the main body of glacier number depression and area recession. Due to shrinkage, the glaciers below 4000 m a.s.1, completely disappeared.