青藏高原多年冻土区地下水及其变化

青藏高原的高海拔多年冻土的分布格局及其动态变化、季节冻结融化作用与地下水的补给、径流和排泄关系密切，对各种尺度的水文地质环境具有控制或重要影响。作为一个隔水层或弱透水层，冻土层在地下水形成、演化、运移和水动力过程方面具有抑制作用，从而对地下水的分布、动态和水循环产生重要影响。而且，冻土可通过其中的水分迁移、冰分凝和地下冰结构重组等方式，形成和改变地下冰储量及地下水动静储量，调节水文地质循环。气候变暖显著和人类活动日益增加，冻土退化显著，已经普遍影响到了高原冻土生态水文地质环境，并引发了一系列水文（地质）、生态和环境问题，亟待系统、长期和细致的观测、试验和模型研究。

Groundwater in the permafrost regions on the Qinghai-Tibet Plateau and it changes

On the Qinghai-Tibet Plateau, the occurrence and distribution of elevational permafrost and its dynamic changes and the seasonal freezing-thawing processes in the active layer are closely related to the recharge, flow paths, and discharge of groundwater. Therefore, permafrost controls or affects the hydrogeology on the plateau. As an aquitard, permafrost greatly limits the development, evolution, movement and hydraulics of groundwater, affecting the occurrence, dynamics and circulation of groundwater. In addition, permafrost can modulate the hydrogeological cycles by forming and changing the storage of ground ice and groundwater through moisture migration, ice segregation, and ground ice structures and textures in permafrost. Under a warming climate and with increasing anthropogenic activities, significant permafrost degradation has been observed and more dramatic degradation of permafrost is anticipated. These changes may affect the ecology and hydrogeology in the permafrost regions with a series of hydrological and hydrogeological, ecological and environmental impacts. These issues urgently call for more systematic, long-term and in-depth research on the observations of, experiments on and modeling in permafrost and ecological hydrogeology on the plateau as a whole, and in several key regions or watersheds, such as the sources areas of the Yangtze River and the Yellow River, as well as in the upper reaches of the Heihe watershed on the northern flanks of the Qilian Mountains.