中文摘要：

青藏高原的季节性冰盖不仅改变局部大气下垫面和气-水-地热交换形式;同时也是交通、水利工程建设不可忽略的因素。作者首次开展青藏高原北麓河地区热融湖塘冰的生消过程和冰内部晶体及气泡特征的现场观测。结果发现热融湖塘冰盖层内存在两类典型气泡,并分为大气泡区和小气泡区,气泡含量随冰的生长而减少。整个冰层为柱状晶体,粒径随深度增加而增大。冰密度随气泡含量的不同而变化较大。本文综合气象和地质因素来分析其形成机理。

英文摘要：

The ice cover in Qinghai-Tibet Plateau is a key factor influencing environmental and ecological conditions since it alters the heat and energy exchange between local atmosphere and permafrost,as well as determines the design and construction of civil engineering. This paper presents the in-situ observations of ice growth and decay,inner crystal and gas bubble of ice cover in a thermokarst lake,in the Beiluhe Basin,Qinghai-Tibet Plateau. It is found that two typical types of gas voids are detected,and the gas content decreases with the increase of depth. The entire ice cover is consisted of columnar-crystal ice,and the size of crystal increases following the growth of ice cover. A large discrepancy of ice density in different locations due to the gas content variation is found. Finally,the forming mechanism of this phenomenon was discussed based on special meteorology and stratigraphy of the Plateau.