变化环境下黄河源区关键水文过程机理及分布式模型研究

In the Yellow River source region, permafrost, alpine wetland and meadow ecosystem has developed a unique system of hydrology and water resources. The current climate change and human activity intensifies vegetation and permafrost degradation, which has a profound impact on hydrology physical processes. In this project, field experiments, numerical simulation and multi-source data will be conducted to study the mechanism of runoff production and routing process at different land surface conditions with different climate conditions. Isotope experimental technique, accompanied with historical experimental data, will be used to examine the mechanism of the interaction among wetland-surface water, soil water, ground water, and frozen melt water at different structure conditions. As a consequence, various modules including surface water, wetland water, frozen soil water, snow and groundwater can be integrated for constructing a distributed hydrological model suitable for high cold regions under the changing environment, and uncertainty factors of the hydrologic simulations under changing environment will be systematically analyzed to clarify the evolution mechanism of hydrological processes in high cold basins. Finally, characteristics of water cycle variation and its potential impacts on the Huanghe River streamflow will be assessed under environment changes. This project will make innovative advances in the evolutional mechanism of watershed hydrologic processes, distributed hydrological simulation, water resources assessment and other fields under the changing environment.

气候变化和人类活动导致黄河源区冻土、高寒沼泽湿地和草甸生态系统退化加剧，对流域水文物理过程产生了深刻的影响，水资源时空分布格局改变。本项目将通过野外观测实验、数值模拟技术和多源数据揭示黄河源区不同下垫面单元、不同气候条件下的产汇流过程演变规律。利用同位素实验观测技术，结合历史实验观测数据，辨识不同条件下沼泽湿地水体、土壤水、地下水及冻土消融的水热交换机制；发展地表水、沼泽湿地水体、冻土水、积融雪以及地下水等水循环模块，构建高寒地区变化环境的分布式水文模型，系统分析变化环境下源区水文模拟的不确定因素，阐明高原沼泽湿地流域水文过程对环境变化的响应机制；最终评估环境变化下黄河源区的水循环要素变化规律及其对径流的影响。本项目将在研究变化环境下高寒流域水文过程演变机理、模拟理论技术和水资源评估等领域取得创新。

本项目通过系统性水循环综合观测和同位素实验及机理研究，分析了黄河源区关键下垫面要素近年来的现状及变化趋势，并建立其与环境因子的关系；在不同冻土分布和冻土退化程度的地区开展多层次的水文机理实验，对同位素（2H、18O、222Rn及3H）及多源数据进行综合分析，对典型流域多水源间的水力联系和水流路径进行示踪研究，揭示了热融湖塘-多年冻土层的动态水文过程转化规律，辨识了热融湖塘及流域的水量平衡模式，查明了多水源水力联系径流分配通道，进一步阐明冻土区水文过程对冻土退化的响应机制；揭示了关键气象和下垫面要素变化对源区河流水文要素的影响，探明了黄河源区变化环境下湖沼湿地、冻土等水文产汇流条件变化过程与机理，揭示了沼泽湿地与冻土退化导致的包气带水分运移规律变化机制；构建了集成高寒地区冻土、湖沼和积融雪等典型水文过程的分布式水文模型，探明有无土壤冻融情况下各子流域地表径流、壤中流和基流的变化规律，量化了冻土退化的对不同径流成分的影响机制，定量区分了人类活动和气候变化对黄河源区径流的影响。项目在变化环境下高寒流域水文过程演变机理、高寒流域分布式水文模拟、环境因子的水文过程反馈等方面取得了创新性成果，为探求气候变化和高强度人类活动干扰下的高寒地区水循环规律提供研究工具和理论基础。在本项目的支持下，发表基金标注的学术论文108篇，其中高水平论文89篇，授权发明专利10项。获得教育部自然科学奖一等奖1项，水利部大禹水利科技进步奖一等奖1项、二等奖1项。培养了博士研究生9名，硕士研究生51名。