中文摘要：

根据1959年和2009年在喜马拉雅山珠穆朗玛峰北坡绒布冰川获得的冰川消融数据, 分析了该冰川消融速率变化特征.结果表明： 1） 在珠峰绒布冰川表碛覆盖区, 表碛厚度随海拔升高而降低. 2） 不同厚度表碛下的冰川消融速率差别较大; 当表碛厚度〉8.5 cm时, 消融速率随表碛厚度的增加而减小; 促进冰川消融的表碛厚度阈值大于5 cm. 3） 从冰川消融速率的空间分布看, 绒布冰川大部分区域的消融速率〈20 mmd-1, 最大消融速率出现在海拔5 400~5 450 m处. 4） 绒布冰川消融速率受表碛厚度和气温综合影响, 低海拔处表碛太厚, 高海拔处气温较低, 冰川消融在上述两海拔处均受抑制, 冰川消融速率较小; 在中海拔处, 表碛相对较薄, 气温相对较高, 冰川消融速率最大; 冰川日均消融速率与日均正积温正相关. 5） 喜马拉雅山南坡冰川消融速率大于北坡冰川消融速率.

英文摘要：

Based on the ablation data obtained in 1959 and 2009, ablation rates of the Rongbuk Glacier, a debris-covered glacier located on the northern slopes of the Mt. Qomolangma, were analyzed in this paper. Debris thickness decreased along with altitude. Ablation rates varied considerably with various thicknesses of debris. When debris thickness was larger than 8.5 cm, glacier ablation rate decreased with the increasing thickness of debris. The threshold debris thickness which could accelerate the glacier melting was larger than 5 cm. Both temperature and debris thickness comprehensively controlled the glacier ablation rate, which could be illustrated in detail as follows： In the low and high parts of this debris-covered glacier, ablation rates were both relatively lower since thicker debris and lower temperature at these two parts mentioned above suppressed glacier ablation, resulted from less energy supplied to the melting front;Nevertheless, in the middle part of the glacier, thin debris together with relatively high temperature led to higher glacier ablation rate. Ablation rate was less than 20 mmd-1 in most parts of the glacier with a maximum ablation rate at the altitude range of 5 400~5 450 m a.s.l. Daily ablation rate was positively correlated with daily mean temperature. Glacier ablation rate in the southern Himalayan was larger than that in the northern Himalayas.