Abstract:
As the core area of the "Asian Water Tower", the Tibetan Plateau serves as the source region of major rivers including the Yangtze, Yellow, Yarlung Tsangpo, Ganges, and Mekong rivers. Highly sensitive to global climate change, the Tibetan Plateau experiences pronounced warming, which profoundly alters watershed hydrological cycles and triggers cascading ecological impacts in mid-lower reaches. The groundwater system, a critical component of hydrological processes, plays a vital role in maintaining baseflow stability and ecosystem equilibrium in river source areas. This study provides a comprehensive review of the structure of the groundwater system, groundwater circulation characteristics in cold regions, and changes in groundwater storage on the Tibetan Plateau. Studies show that the total terrestrial water storage on the Tibetan Plateau is decreasing, while groundwater storage is increasing in some areas. Climate change has accelerated the conversion of surface solid water, such as glaciers and snow, into groundwater. Groundwater discharge through baseflow maintains river runoff during the dry season, and this cycle will be further intensified as permafrost degrades. However, the representation and simulation of the "variable aquifer" in permafrost remains a significant challenge for groundwater modeling. Shallow groundwater levels are essential for maintaining the alpine grassland ecosystem, and the increase in permafrost activity layer thickness leads to a decline in groundwater levels, which could trigger vegetation community succession. Moreover, as snow and ice melt and permafrost degrades, soil moisture and subsurface flow increase on mountain slopes, raising the risk of geological disasters such as landslides. Future research should focus on enhancing observation networks, integrating diverse data sources, and developing groundwater system models that incorporate permafrost elements. Promoting interdisciplinary research across hydrology, geology, ecology, and engineering will improve the understanding and management of groundwater changes. These efforts will provide scientific support for addressing climate change, ensuring sustainable water resource management, and protecting the ecosystem in the "Asian Water Tower" region.