科其喀尔冰川表碛区冰崖形态调查

Investigation of Ice Cliffs in the Debris-covered Area of Koxkar Glacier,Tianshan

采用随机抽样的方法对科其喀尔冰川表碛区冰崖的规模及形态进行了调查.在冰崖比较集中的表碛区东侧任意选取了20个冰崖,利用测绳、皮尺并结合GPS测量的方法对冰崖的长度和高度进行了调查,同时用地质罗盘对冰崖的坡向和坡度进行了测量,从而了解冰崖的长度、高度、坡面面积、坡向和坡度等形态特征及其关系.对冰崖形态的分析表明,消融区内冰崖的规模相差很大,且随着海拔高度的增加,冰崖规模有减小的趋势;这可能主要与地形起伏随海拔高度的差异性变化有关,消融区下部冰崖表面消融过程较为活跃也是一个重要的因素.通过对冰崖的坡向和规模之间的分析可以看到,坡向为NW和NNE方向的冰崖最多,其规模也较大,而太阳直接辐射是影响冰崖发育坡向和发育规模的重要因素.

In this paper, investigation of scale and shape of 20 random selected ice cliffs in the debris -covered area of Koxkar Glacier is presented to explore the basic characteristics of ice cliffs. Tapelines, together with GPS equipments, are used in length and height measures of ice cliffs, and geological compass is utilized to survey orientation and slope angle of ice cliffs. Bare ice area of the ice cliffs is calculated from the length and height data. Analysis on these basic conformation data of ice cliffs shows that the scale of ice Cliffs varies dramatically. The ice cliffs present a trend of decrease in size with altitude. The mechanism is the hypsography changing with altitude and the ice abla- tion decreasing from the lower ablation area tO the upper ablation area. Moreover, investigation on the relationship between orientation and scale of the ice cliffs indicates that orientations of most ice cliffs are NW and NNE, along which ice cliffs also have the great scale. Analysis suggests that the direct solar radiation is the dominant factor that governs the distribution and evolution of ice cliffs.