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冰川冻土 ›› 1985, Vol. 7 ›› Issue (1): 27-40.

• 研究论文 • 上一篇    下一篇

天山乌鲁木齐河源1号冰川的运动特征

孙作哲, 陈要武, 尤根祥, 韩建康   

  1. 中国科学院兰州冰川冻土研究所
  • 收稿日期:1984-10-11 出版日期:1986-02-25 发布日期:2012-04-26

Flow Characteristics of Glacier No.1 at the Headwater of Urumqi River, Tianshan

Sun Zuozhe, Chen Yaowu, You Genxiang, Han Jiankang   

  1. Lanzhou Institute of Glaciology and Geocryology, Academia Sinica
  • Received:1984-10-11 Online:1986-02-25 Published:2012-04-26

摘要: 天山乌鲁木齐河源1号冰川位于天山中部喀拉乌成山脉北坡的乌鲁木齐河源,是一条冰斗-山谷冰川。全长2.33公里,面积1.84平方公里,由东、西两支冰川组成。冰斗后壁最高峰海拔4483.6米,冰舌末端3734米。冰面较为平整、洁白,裂隙不甚发育。 1号冰川的运动观测开始于1959年。1962年张长庆对前三年的运动资料进行了总结。1973年8-9月王文颖对该冰川的15个流速点作了短期观测,并和1962年的运动状况作了对比。本文在1980年以来两年多的冰川运动进行观测的基础上,应用冰川学的基本理论,对所得资料进行分析研究,以期对1号冰川的运动特征有较为深刻的认识。

Abstract: The flow measurement of Glacier No. 1 has been taken since 1980 and data have been analysed on the basic theory of glaciology. Following characteristics are noticeable:1. Both tributaries of Glacier No. 1 have two areas with high speed. At the western one, the first located on c-profile is due to the narrowing of the channel, the second occupies the region beyond i-profile because the cirque back-wall is with steep slope. The variation of the longitudinal velocity profile on the eastern tributary,with high velocity areas occurring near i′-and d′-profile respectively, is less serious than that on the western. The transverse profiles of flow velocity, in general, opposite to the situation of ice motion in valley glacier, show obvious asymmetry which reflects the character of the channel.2. Velocity vectors near the snow-line run parallel to the slope of ice surface, while in accumulation area they are inclined into the ice and in the glacial tongue area they point from inside the ice to ice surface. This is similar to that found in other cirque and valley glaciers. Velocity vectors in Glacier No.1, with exception of b-profile on western tributary, all converge towards flow centre-line. This anomaly in ablation area is caused by the narrowing of the channel in the lower reaches. Divergence of vectors, which should appear in the glacial tongue area, is offset by the convergence.3. Velocity on c-profile at western tributary has a day and night variation with a propertion of 2,42: 1. From measurements we see that as a process ice flow contains a series of jerks.Comparison between the two meassurement years, i. e. 1980-1981 and 1981-1982, shows that the velocity on western tributary became lower, while on eastern tributary, in contrast, went up. Daily mean velocity obtained during ablation seasons in 1980 was 30% less than in 1973. And annual velocity in May 1980-May 1981 was lowered 31-73% than the arerage of 1959-1962. This resulted from the thinning of ice and the flattening of ice slope. Comparison of maps drawn in 1973 and in 1980, shows that thinning of ice mass at different degree took place at both tributaries. In ablation area, the eastern tributary thinned more strongly than the western one, while in accumulation area, conversely. Near the snow-line of the western tributary, ice surface lowered by 8 m, and velocity decreased by 67%.4. There exists obvious emergence velocity on Glacier No. 1. It can offset ice ablation by 0.25-0.5 or so. Thus, it is reasonable to think that in order to keep the balance in ice mass in ablation area, ice must be continuously transported here, It depends on both horizontal and emergence movement components.