SCIENTIA GEOGRAPHICA SINICA ›› 2023, Vol. 43 ›› Issue (4): 754-762.doi: 10.13249/j.cnki.sgs.2023.04.019

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Impact factors of the threshold altitude for glacier development on the eastern Tibetan Plateau

Cui Hang1,2(), Mu Haizhen1,2   

  1. 1. Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, Qinghai, China
    2. Qinghai Province Key Laboratory of Physical Geography and Environmental Process, College of Geographical Sciences, Qinghai Normal University, Xining 810008, Qinghai, China
  • Received:2022-01-20 Revised:2022-04-15 Online:2023-04-30 Published:2023-04-20
  • Supported by:
    National Natural Science Foundation of China(41801032);National Natural Science Foundation of China(42161003)

Abstract:

Elevation is a very important factor for glacier development on the Tibetan Plateau and the glacier equilibrium line altitude (ELA) is the lowest limit for glacier development. However, on the Tibetan Plateau, previous studies about how many meters above the ELA of mountains can develop glacier is still scarce. Based on the glacier-climate model, the threshold altitude for glacier development (Ht) in the north and south slope of Burhan Budai Mountain, Dalijia Mountain, La Ji Mountain, east and west slope of Gongga Mountain, and Haizi Mountain on the eastern Tibetan Plateau are 5320 m, 5390 m, 4740 m, 4881 m, 4894 m, 5114 m and 5414 m, respectively and the ELA of these mountains are 5231 m, 5305 m, 4736 m, 4793 m, 4878 m, 5085 m and 5406 m respectively. Thus, the difference (Δh) between the Ht and ELA of these mountains are 89 m, 85 m, 4 m, 24 m, 16 m, 29 m and 8 m, respectively. Based on the comparative analysis of the topography, climate and relief of the five mountains in the study area, our results indicate that the changes in ice volumes on the Gongga Mountain and Burhan Budai Mountain are consistent with their positive difference of glaciation. With greater positive difference of glaciation, the size of glaciers in Gongga Mountain is larger than that of Burhan Budai Mountain. Generally speaking, the difference in slope above ELA during last glacial maximum (SELA) makes the Δh of Dalijia Mountain and Haizi Mountain, which were occupied by ice cap during late Quaternary, smaller than that of Burhan Budai Mountain, La Ji Mountain and Gongga Mountain, which mainly developed valley glaciers since the late Quaternary. Compared with other mountains in the study area, the extremely low annual precipitation at the ELA of Burhan Budai Mountain makes its Δh the largest. The Δh of the Dalijia Mountain is the smallest due to the relatively abundant annual precipitation at ELA and the relatively gentle SELA. In the marine glacial area, the lower average summer temperature at ELA and the gentler SELA make its Δh smaller than that of Gongga Mountain. The differences of Δh between east and west slope of Gongga Mountain are mainly affected by their annual precipitation at ELA. In continental glacial area, the differences of Δh between Burhan Budai Mountain, La Ji Mountain and Dalijia Mountain are dominated by the changes in annual precipitation at ELA. As a consequence, the differences of Δh between different mountains in the study area are controlled by changes in annual precipitation at ELA and SELA. This article preliminarily researches the impact of climate differences (or changes) on Δh based on the comparison of different mountains. Climate is the greatest factors impacted on the development of glaciers. Changes in climate will cause changes in the surface environment of earth and this will introduce errors for model because of our simulation commonly based on modern conditions. In addition, quantitative paleoclimatic reconstructions are scarce in glaciated areas, which restrict the application of the model. Further research should be applied to explore the changes in Ht under climate fluctuations based on more robust paleoclimate data.

Key words: the Tibetan Plateau, glacier development, equilibrium line altitude

CLC Number: 

  • P512.4