Metamorphism and Microstructure of Seasonal Snow:Single Layer Tracking in Western Tianshan,China

作     者：HONG Wen WEI Wen-shou LIU Ming-zhe LU Heng HAN Xi ZHANG Yan-wei 

作者机构：Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences Graduate School of Chinese Academy of Sciences Institute of Desert MeteorologyChina Meteorological Administration Tianshan Station for Snow Cover and Avalanche Research College of Environment and Planning Shangqiu Normal University 

出 版 物：《Journal of Mountain Science》 (山地科学学报（英文）)

年 卷 期：2014年第11卷第2期

页      面：496-506页

核心收录：

学科分类：0709[理学-地质学] 0819[工学-矿业工程] 07[理学] 070601[理学-气象学] 0303[法学-社会学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 0705[理学-地理学] 0815[工学-水利工程] 0706[理学-大气科学] 0816[工学-测绘科学与技术] 0813[工学-建筑学] 0704[理学-天文学] 0833[工学-城乡规划学] 0713[理学-生态学] 0834[工学-风景园林学（可授工学、农学学位）] 

基　　金：supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of China (Grant No.2012BAC23B01) National Natural Science Foundation of China (Grant No.41171066) the R&D Special Fund for Public Welfare Industry of China(Grant No.GYHY201206026) 

主　　题：动力变质作用 西天山 积雪 金相组织 跟踪 中国 季节性 单层 

摘      要：Snowpack is a combination of several snow layers. Accordingly, snowpack natural metamorphism is composed of several stages. The aim of this study is to investigate the natural snow metamorphism at the snow layer unit. The field investigation was conducted at the Tianshan Station for Snow Cover and Avalanche Research, Chinese Academy of Sciences(43°16 N, 84°24 E, and 1,776 m a.s.l.), during the winter of 2010-2011. A complete metamorphic procedure and the corresponding microstructure of a target snow layer were tracked. The results indicate that: the ideal and complete metamorphic process and the corresponding predominant snow grain shape have 5 stages: 1) unstable kinetic metamorphism near the surface; 2) unstable kinetic metamorphism under pressure; 3) stable kinetic metamorphism; 4) equilibrium metamorphism; 5) wet snow metamorphism. Snow grain size sharply decreased in the surface stage, and then changed to continuously increase. Rapid increase of grain size occurred in the stable kinetic metamorphism and wet snow metamorphism stage. The characteristic length was introduced to represent the real sizes of depth hoar crystals. The snow grain circularity ratio had a variation of rapid increase–slow decrease–slow increase, and the snow aggregations continuously increased with time. Snow density grew stepwise and remained steady from the stable kinetic to the equilibrium metamorphism stage. The differences in metamorphism extent and stages among snow layers, led to the characteristic layered structure of snowpack.