Three-dimensional numerical simulation of glacial trough forming process  

作　　者：YANG ShaoHua SHI YaoLin 

机构地区：[1]Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences, University of Chinese Academy of Sciences

出　　处：《Science China Earth Sciences》2015年第9期1656-1668,共13页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.41174067)

摘　　要：The glacial trough is a common glacier erosion landscape, which plays an important role in the study of glacier erosion processes. In a sharp contrast with the developing river, which is generally meandering, the developing glacial trough is usually wide and straight. Is the straightness of the glacial trough just the special phenomenon of some areas or a universal feature? What controls the straightness of the glacial trough? Until now, these issues have not been studied yet. In this paper, we conduct systematic numerical models of the glacier erosion and simulate the erosion evolution process of the glacial trough. Numerical simulations show that:(1) while the meandering glacier is eroding deeper to form the U-shaped cross section, the glacier is eroding laterally. The erosion rate of the ice-facing slope is bigger than that of the back-slope.(2) The smaller(bigger) the slope is, the smaller(bigger) the glacier erosion intensity is.(3) The smaller(bigger) the ice discharge is, the smaller(bigger) the glacier erosion intensity is. In the glacier erosion process, the erosion rate of the ice-facing slope is always greater than that of the back-slope. Therefore, the glacial trough always develops into more straight form. This paper comes to the conclusion that the shape evolution of the glacial trough is controlled mainly by the erosion mechanism of the glacier. Thereby, the glacial trough prefers straight geometry.The glacial trough is a common glacier erosion landscape, which plays an important role in the study of glacier erosion pro- cesses. In a sharp contrast with the developing river, which is generally meandering, the developing glacial trough is usually wide and straight. Is the straightness of the glacial trough just the special phenomenon of some areas or a universal feature？ What controls the straightness of the glacial trough？ Until now, these issues have not been studied yet. In this paper, we con- duct systematic numerical models of the glacier erosion and simulate the erosion evolution process of the glacial trough. Nu- merical simulations show that： （1） while the meandering glacier is eroding deeper to form the U-shaped cross section, the glacier is eroding laterally. The erosion rate of the ice-facing slope is bigger than that of the back-slope. （2） The smaller （bigger） the slope is, the smaller （bigger） the glacier erosion intensity is. （3） The smaller （bigger） the ice discharge is, the smaller （big- ger） the glacier erosion intensity is. In the glacier erosion process, the erosion rate of the ice-facing slope is always greater than that of the back-slope. Therefore, the glacial trough always develops into more straight form. This paper comes to the conclu- sion that the shape evolution of the glacial trough is controlled mainly by the erosion mechanism of the glacier. Thereby, the glacial trough prefers straight geometry.

关 键 词：glacial trough erosion action numerical simulation finite element method 

分 类 号：P343.6[天文地球—水文科学] TU457[天文地球—地球物理学]