典型流域径流组分多源示踪技术及不确定性研究

Using the method of hydrogen, oxygen stable isotopes combining with water chemical ion determination and physical hydrology measurement, the paper made a tracer method study on the isotopic composition, the distribution and change regulation of runoff components (surface runoff, soil and groundwater runoff) under rainfall condition of two typical watershed: the mountains and the plain. And two-components and three-components isotope hydrograph separation mode had been constructed. The reliability of models were studied by using the Monte Carlo methods and the problem about reliability of model output result from the temporal and spatial variability of tracer concentrations of components. Through the indoor model simulation and the wild field test of combining research tools, and use parallel experiment design concept, the factors of aeration zone which largely influence the results of hydrograph separation model were studied. With lager underground lysimeter in test base, different depth (0-5 m) aeration zone soil water samples were taken and hydrogen and oxygen stable isotopes and determined water chemical ion content were analyzed. The research on the isotopic composition of water seeping out of different quality of a material soil column under the natural rainfall condition, the variation characteristics, and its influenced factors, discovery of the movement features of aeration zone water and changes discipline on the condition of different rainfall intensity and different underlying surface soil type can provide the scientific basis for the more accurate separation of the runoff components.

径流成分的划分结果对流域汇流计算甚至水资源评价均会产生显著影响。以稳定同位素及水化学离子等作为示踪剂的多源示踪技术是确定径流成分来源的重要手段，但目前对示踪法应用中的不确定性研究不足，缺乏对不确定性的完整、科学的量化描述。本研究拟对径流组分的示踪剂浓度的时空变化性所引起的模型计算结果的不确定性进行分析，并运用Monte Carlo 方法对模型的可靠性进行模拟研究。对径流组分划分模型的计算结果影响较大的包气带因素，通过室内模型模拟和野外现场试验相结合的研究手段，运用并行实验设计理念，借助大型地中蒸渗仪对不同深度（0-5m）的土壤水进行采样并进行对比分析，尽可能降低由于土壤水中的同位素横向弥散因素浓度分布的各向异性问题对模拟结果的影响。研究成果将为更合理地划分径流成分提供科学依据，为区域水资源评价、涉水工程建设及水资源的合理开发利用提供技术支撑，具有良好的理论和应用价值。

本项目着眼于应用同位素示踪方法划分实验流域的径流组分，以淮河五道沟实验基地作为主要的研究区。以稳定同位素及水化学离子等作为示踪剂的多源示踪技术来确定径流成分来源。本研究对径流组分的示踪剂浓度的时空变化性所引起的模型计算结果的不确定性进行分析，并运用Monte Carlo 方法对模型的可靠性进行模拟研究。对径流组分划分模型的计算结果影响较大的包气带因素，通过室内模型模拟和野外现场试验相结合的研究手段，运用并行实验设计理念，借助大型地中蒸渗仪对不同深度（0-5m）的土壤水进行采样并进行对比分析，尽可能降低由于土壤水中的同位素横向弥散因素浓度分布的各向异性问题对模拟结果的影响。研究成果为更合理地划分径流成分提供科学依据，为区域地表/地下水资源评价、涉水工程建设及水资源的合理开发利用提供技术支撑，具有一定的应用价值，为传统流量过程线的图解划分结果提供了一个更有物理依据的校正手段。