青藏高原热喀斯特湖与多年冻土的相互作用

为深入理解热喀斯特湖与多年冻土间的相互作用，本文以青藏高原北麓河盆地典型热喀斯特湖区域为例，构建考虑热传导和热对流过程的水-冰-热耦合模型，对热喀斯特湖作用下的多年冻土退化特征及热喀斯特湖的水均衡进行模拟，计算地质环境和气候变暖对热喀斯特湖水均衡和冻土的影响。研究结果表明：热喀斯特湖周围冻土逐步退化并形成贯穿融区，导致地下水循环模式发生改变；在地表温度作用下，形成的活动层厚度为3.35 m;热喀斯特湖在整个模拟时段内表现为负均衡，其排泄量在285～388 a间显著增加；地层渗透性能决定了热喀斯特湖和生态环境的发展方向；气候变暖加速多年冻土向季节冻土转变。研究结果可为进一步认识寒旱区生态水文过程提供科学依据。

Interaction of thermokarst lake and permafrost in Qinghai-Tibet Plateau

In order to clarify the interaction of thermokarst lake and permafrost, a water-ice-heat coupling model considering heat conduction and convection processes was established at a typical thermokarst lake area in the Beiluhe Basin. The degradation characteristics of permafrost and the water balance of thermokarst lake were simulated. Furthermore, the effects of the geological environment and climate warming on permafrost and water balance of thermokarst lake were analyzed. Results showed that the permafrost around the thermokarst lake degraded gradually, resulting in a melt-through zone, causing the groundwater circulation mode to change. The thickness of the active layer was 3.35 m under the effect of the ground-surface temperature. Thermokarst lake exhibited a negative balance during the entire simulation period and its discharge increased significantly during the 285—388 years. Additionally, the formation permeability determined the development directions of thermokarst lake and ecological environment; climate warming accelerated the conversion of permafrost into seasonal frozen soil. This study can provide references to understanding of eco-hydrological processes in cold and arid regions.