Some Relationships of the Fluctuation of Glacier No.1 with Climatic Change at the Source of Urumqi River, Tianshan
Zhang Xiangsong, Sun Zuozhe, Zhang Jinhua and Kang Xingcheng (Lanzhou Institute of Glaciology and Geocryology, Academia Sinica)
Three ways of research on the complicated relationship between glacial fluctuation and climatic changes are applied at present! (1) Explaining the direct relationship between glacial fluctuation and climatic changes so as to provide a climatic model for the explanation of glacial behaviour;(2) Quantitatively modelling the response of glacial behaviour on change of mass balance and theoretical analysis of very sensitive respondent properties of glacial terminus on climatic changes; (3) Explaining the variation of Switzerland glaciers in 1891-1965 with the relationship between glacier and weather. The areal distribution of Glacier No.l has large influence on the annual change of mass balance,because the range of annual variation of the altitute of the equilibrium line locates just within the maximum area of the distributive region of the glacier. The empirical relationship between, the altitude (EL) of equilibrium line and the net mass balance (M) has been found as: EL= 4038.1 - 0.16 M. Correlation coefficient is -0.78. Comparative results of topographic maps of different periods indicate that Glacier No.l has continuously retreated since 1962. But the retreating rate is obviously different: 5 .96 m/yr. during Sep. 1962-Aug. 1977; 3.28 m/yr.during Aug.1973-Aug.1980 and 4.83 m/yr.during Aug.1980-Aug.1981. Inference of climatic changes and glacial behaviour in drainage area of Urumqi River from tree ring data during the Little Ice Age is shown in Table 2. From these three methods we come to the conclusion that the state of degradation of Glacier No. 1 at present will still continue for a considerable time, at least before 1990.