祁连山大通河源区冻土特征及变化趋势  

The characteristics and changing tendency of permafrost in the source regions of the Datong River,Qilian Mountains

作　　者：王生廷 盛煜[1] 吴吉春[1] 李静[1] 陈继[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049

出　　处：《冰川冻土》2015年第1期27-37,共11页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(41271084);国家自然科学基金创新研究群体项目(41121061);国家重大基础研究发展计划(973计划)项目(2013CBA01803)资助

摘　　要：大通河源区位于祁连山中东部,属高山多年冻土区,利用源区内冻土钻探及监测资料对源区冻土发育的基本特征及变化趋势进行了分析和探讨.冻土地温分析表明,源区冻土年平均地温随海拔的变化梯度约为3.82℃·km^-1,且冻土地温与表层覆被条件关系密切.盆地平原地带多年冻土厚度约为17～86 m,且以海拔每上升100 m冻土厚度增加约10 m的梯度增加.多年冻土活动层厚度受海拔地带性作用不显著,更多地受局地因素的控制,地表覆被条件成为其主要影响因素.在气温升高以及人类活动日益增多的影响下,源区冻土整体处于退化状态,多年冻土年平均地温以0.0075℃·a^-1的速率上升.The source regions of the Datong River are located in the mid-east part of the Qilian Mountains with alpine permafrost. The characteristics and changing tendency of the permafrost were analyzed by using data from boreholes and surface observation. Regression analysis indicates that the mean annual ground temperature of permafrost in the source regions decreases with altitude with a gradient of about 3. 82 ℃ · km^-1. The mean annual ground temperature within the permafrost is affected by surface condition closely. The permafrost depth in the source regions is also significantly dependent on altitude. With the rising of elevation by 100 m,the thickness of permafrost increases about 10 m. In the plain areas,the depth of permafrost is ranging from 17 to 86 m.Active layer thickness is closely related to local factors,especially land cover condition. There is no clearly zonality relationship between active layer thickness and altitude. Under the impact of rising temperature and human activities,permafrost in the source regions is overall in the state of degradation,and the mean annual ground temperature is increasing at a rate of about 0. 0075 ℃ ·a^-1.

关 键 词：大通河源区 冻土分布 年平均地温 活动层 退化 

分 类 号：P642.14[天文地球—工程地质学]