天山乌鲁木齐河源1号冰川物质平衡高度变化特征及其对径流的影响

利用天山乌鲁木齐河源1号冰川1980-2010年的物质平衡、水文气象实测资料, 分析了1号冰川1980-2010年的各高度带物质平衡特征, 进而分析了1984-2010年纯积累和纯消融的变化特点及其与气象要素、冰川融水径流变化的关系. 结果表明: 1号冰川物质平衡处于持续的负平衡, 纯积累量与年降水的相关系数为-0.16, 纯消融量与年均温的相关系数为0.61, 与夏季(6-8月)气温的相关系数为0.78. 2010年1号冰川为有观测记录以来的最强消融年(b_n=-1 327 mm), 整个冰川处于消融区(平衡线高度大于海拔4 484 m, 积累区面积为0), 同时东、西支冰川各高度区间的物质平衡变化也与往年度显著不同, 说明2010年是1号冰川物质平衡变化的特殊年份, 也有可能1号冰川的物质平衡变化进入了一个新的亏损变化阶段. 对其径流数据的分析还表明, 温度对径流的影响大于降水对径流的影响.

Characteristics of the altitude-dependent mass balance and their impact on runoff of the Glacier No.1 at the headwaters of the Ürümqi River,Tianshan Mountains

Based on the observation of surface mass balance from 1980 to 2010 on the Glacier No.1 at the headwaters of the Ürümqi River, Tianshan Mountains, together with hydrological and meteorological data, the relationships between net ablation and climatic factors and between net accumulation and climatic factors during 1984-2010 are studied. In addition, characteristics of mass balances in different altitude ranges and their impact on runoff of the glacier are analyzed. It is found that in the Glacier No.1 mass balance is in a continuous deficit situation. A statistical analysis shows that the correlation coefficient is -0.16 between net accumulation and precipitation; the correlation coefficient is 0.61 between net ablation and annual mean air temperature; the correlation coefficient is 0.78 between net accumulation and the summer mean air temperature; in 2010 both annual net accumulation and accumulation area reached the minimum in the record since observation; in 2010 both annual net ablation and ablation area reached the maximum in the record since observation. 2010 was the strongest ablation year (b_n=-1 327 mm), when the Glacier No.1 was totally in the ablation zone (ELA>4 484 m). Most notably, mass balances in various altitude ranges of the glacier, whatever in east branch or in west branch, were significantly different from those in previous years. These suggest that 2010 was a special year of mass balance and that mass balance of the glacier seems to enter a new stage. It is also revealed that the influence of air temperature on runoff is greater than that of precipitation.