过去44年乌鲁木齐河源一号冰川物质平衡结果及其过程研究

Study on Mass Balance and Process of Glacier No.1 at the Headwaters of the Urumqi River in the Past 44 Years

通过1997-2003年度天山乌鲁木齐河源一号冰川物质平衡的观测结果,分析比较了过去44年间一号冰川物质平衡、累积物质平衡的变化过程,以及反映气候-地形要素和冰川发育条件要素的平衡线高度和冰川积累区比率,认为一号冰川负平衡波动期随时间推移而递增,目前处于其观测历史上物质平衡亏损最为强烈的时期。

Glacier No.1 is located at the headwaters of the Urumqi River,Tianshan Mountains,and it wascomposed of 2 glacier braches before 1993,but it has been divided into two separate glaciers since the end of1993 due to the shrinkage of the west glacier branch. Its area was reduced from 1.95 km2 in 1962 to 1.742 km2(1.115 km2+0.627 km2) in 1994 and 1.708 km2 (1.101 km2+0.607 km2) in 2001. The glacier area was reducedby 0.034 km2 in recent 7 years from 1994,and the annual reduction was 2.8%. In this paper,the observed resultsof mass balance of Glacier No.1 during the period from 1997 to 2003 are discussed. The mass balance of GlacierNo.1 in past 44 years,change process of cumulative net balance as well as equilibrium line altitude (ELA) andaccumulation area ratio (AAR),which reflect the topographic and climatic factors and glacier growth conditions,are compared and analyzed. The results show that 8 fluctuations of positive mass balance and 9 fluctuations ofnegative mass balance of Glacier No.1 occurred in past 44 years,and the glacier was still in ninth fluctuation ofnegative mass balance in 2003. The fluctuations of positive mass balance occurred during the period of1963~1996,and the durations of the last three fluctuations during the period from 1975 to 1996 became shorterand shorter,i.e.,from 3 years to 2 years and 1 year. The fluctuation of negative mass balance occurred during thewhole 44-year period from 1960 to 2003,their durations were for 1,2,3,5 and 7 years respectively and becamelonger and longer,i.e.,from 3 years to 5 and 7 years,and the glacier is currently in the most serious deficit sinceobservation.