Mass Balance and Water Exchange of Hailuoguo Glacier in Mount Gongga and Their Influence on Glacial Melt Runoff
XIE Zi chu 1, SU Zhen 2, SHEN Yong ping 2, FENG Qing hua 1 (1.Institute of Resources and Environment of Hunan Normal University. Changsha Hunan 410081, China; 2.Cold and Arid Regions Evironmental and Engineering Research Institute, CAS. Lanzh
Hailuogou Glacier, which lies in an area with largely varied elevation, is a glacier with rich accumulation, heavy melting and large flow velocity. In the early 1990's, its mass balance was calculated by using different methods, and the results differ remarkably. Since more data were obtained in the last 10 years, it is possible to calculate its mass balance with new methods. Using the ELA 0 method and the observed melting data obtainel in 1990—1998, then we get b n= -488 mm. If we use the maximum entropy method and the observed meteorological as well as hydrological data obtained in 1988—1997, then b n= -451 mm. These two values are very close and their average value b n= -470 mm which is close to the mass balance of the glaciers in the High Asia periphery mountain areas in the last 10 years. Based on the parameters for mass balance, the calculated amplitude of mass balance for Hailuogou Glacier is 2 544 mm, and the water exchange level is 3 819 mm which the liquid water accounts for one third of. this ratio is the high values for glaciers in the High Asia. Meanwhile, the stability cofficient, which is the ratio of the seasonal water exchange amount to the multiple year amount, is low ( k =0 20). The negative mass balance of the glacier has giver rise to an increase in discharge. It is estimated that the discharge in 2020s will fall back to the original level just before increasing (critical level). The sensitivity analysis on the response of glacier mass balance to meteorological Variations shows that, a 1 K increase of air temperature or a 10% reduction of precipitation, the responsive values for b n are -214 mm and 354 mm respectively. On the condition that the climate continues getting warmer and more meist, the time at which the discharge reaches to the critical level will proloug to about 2050s. Then the area and volume of the glacier will greatly decrease, which will have great impact on the ecological environment of the upper reach of the Yangtze River.