Classification of Mountain Glaciers Based on Energy

WANG Zong-tai (Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China)

glacier classification; glacier system; glacier energy; internal energy; specific internal energy of glacier.

In this paper, the energy conversion of glacial cryogenic thermodynamic systems in the change of glacier state is calculated and analyzed by using the thermodynamics theory. It is considered that a glacier is a cryogenic thermodynamic system, and its internal energy is called glacier energy. The analyzed results reveal that the change of internal energy of glaciers is different with the change of physical properties of glaciers. Thus, the annual change of internal energy per unit glacier area near the glacier zero equilibrium line is called as the "specific internal energy of glacier", and expressed by u 〔J/(cm 2/a)〕. The calculation equation is as:u=P(334.88+2.093Δt)+55 506.36 d. Where, P is the annual precipitation near the zero equilibrium line; d is the annual saturation deficit near the zero equilibrium line; and Δt is the temperature difference between the initial state and the final state of the glacier near the zero equilibrium line. Glaciers are the low-temperature thermodynamic systems. The energy conversion of glaciers is calculated and analyzed based on the thermodynamic theory; thus, the u values of 34 mountain glaciers in the different regions in the world are derived to be as the indexes of the energy classification of glaciers. According to the statistical results, the glaciers are classified into 2 main types, i.e., the high-energy glaciers when their u values are higher than 100 000 J and the low-energy glaciers when their u values are lower than 100 000 J. The classification is not only an academic study, but also can provide the quantitative parameters for economic activities and engineering application. The 2 types of glaciers are quite different in physical properties and energy effects, for example, the high-energy glaciers are developed under the warm-humid climatic conditions, the glaciers are characterized by the violent melt, rapid movement, abundant water resources, low stability, strong capability of erosion and deposition, frequent occurrence of glacial disasters, etc., and the situation of the low-energy glaciers are contrary. Six sub-types of glaciers are classified, and there are only four in China.