环境示踪剂辅助的高寒山区融雪径流过程模拟研究

Snowmelt off the alpine cold mountains contributes significantly to the river flowing in the inland arid basins. And the quantitative research on response of river flowing to the processes of snowmelt has been the important issues of Catchment hydrology. Our objective here is to develop a tracer aided model of snowmelt runoff generation in small headwater catchments in inland area, NW China. Water samples from stream, snowmelt, rainfall, soil water, and groundwater will be collected between March and November from 2015 to 2016, which is the period of seasonal snow melting and concentrated rainfall within Hongnigou Catchment, and then be analyzed for environmental tracer (2H, 18O, dissolved silica) in laboratory. Two and three component hydrograph separations will be used to identify the temporal and spatial sources of streamwater during snowmelt based on the data of 2H, 18O and dissolved silica. Three end member mixing analytical approach will be employed to trace flow paths in the catchments based on the environmental tracer data. The distributed information of snow, vegetation, land use and soil type will be extracted from remote sensing data. The high resolution digital elevation model (DEM) will generated from Airborne LiDAR data. And then the stream network and topography data will be extraced by the DEM. The tracer aided catchment model(TACD) will be developed based on the understanding of source waters and flow paths in Hongnigou catchment. The dissolved silica data will be served as response data to assess and validate the model.

高寒山区的融雪径流是内陆干旱区的重要补给水源，河川径流对融雪过程响应的定量研究一直是流域水文学的重要议题。基于融雪径流的形成过程和机制来刻画流域产、汇流过程的分布式融雪径流模型已成为流域融雪径流研究的研究热点。本研究选取黑河上游红泥沟小流域为研究对象，采用环境示踪剂定量识别融雪期间河道径流的水分来源和流动路径，结合不同水文输入方式和冻土下垫面对融雪径流过程的影响，建立基于环境示踪剂辅助的分布式融雪径流概念模型。通过融雪水/降雨、土壤水、地下水、河水的稳定同位素（18O）数据与分布式水文模型相耦合，构建环境示踪剂辅助的融雪径流数值模型，最后利用可溶性SiO2示踪结果对融雪径流模型进行校正和检验。通过该研究，以期为改善高寒山区基于物理过程的分布式水文模型提供一种新方法和新思路，为流域生态－水文过程的相互作用机理、水文过程对气候变化的响应机制等研究提供支撑。

本研究选取黑河上游红泥沟小流域为典型研究区，基于环境同位素和反应溶质示踪剂，选取夏季典型降雨-径流事件，定量识别河道径流水分来源和流动路径的动态变化。在此基础上，构建基于物理过程的分布式降雨-径流模型。论文主要开展了以下几个方面研究：高精度DEM刻画高寒小流域河网特征、高寒小流域表层土壤特征、流域季节性冻土土壤冻结过程中的水热变化特征及数值模拟、环境同位素和反应示踪剂指示的降雨-径流事件的形成过程、分布式降雨-径流模型的构建及径流水分来源模拟，以期为高寒山区径流形成机制的分析、气候变化和人类活动对径流过程的影响预测及流域水资源的科学管理等提供依据。