概念水文模型的假设检验和尺度分析

The prevailing approaches in current hydrologic modeling studies are conceptual models. These models generally employ assumptions and simplifications to approximate the real hydrologic systems. The applicability of such models, however, is usually evaluated with the model efficiency in simulating real hydrological processes. Such black-box type approach cannot provide detailed information for the accuracy of the basic assumptions in conceptual hydrologic models. This study will apply a multi-dimensional model based on equations of mathematical physics that more accurately describe the hydrologic system combined with field measured hydrologic data to examine applicability of conceptual hydrologic models. This approach is able to generate detailed spatial and temporal information of hydrologic variables through simulating actual hydrologic processes in watersheds so that it is able to provide systematic information for conceptual model examination. In this study, the model HydroGeosphere featured 3D subsurface domain, 2D surface domain, unsaturated/saturated subsurface flow simulation approach and a fully distributed modeling structure will be used to simulate the well-gauged Hemuqiao watershed in Zhejiang Province. Field observation and sampling combined with laboratory analysis for soil hydraulic properties will provide basic information for the modeling study. The modeling results will thus provide detailed spatial and temporal distribution of key hydrological variables, both surface and subsurface. Such distributed information can then be used to examine the basic assumptions and simplifications of the Xinanjing model, a representative conceptual hydrologic model, and to determine its applicability for various hydrologic, geomorphic and meteorological conditions from theory. This approach overcomes the limitation of inadequate information in data-based model evaluation approaches therefore reduces uncertainties in the analysis. It is also allows hydrologists gain insights of the physical mechanisms of hydrologic approaches, which will contribute to future development of hydrologic modeling approaches.

目前通用的流域水文模型以概念模型为主，它们均是通过一定的假定及简化来近似真实水文系统的运作。对于这类模型的适用性目前主要通过实际模拟效果来检验，因而对其基本假定的检验是经验性的黑箱方法，不能提供其物理机理的详细信息。本研究将使用基于数学物理方法的多维模型结合野外流域观测来检验概念模型的假设适用性。运用这种模型来模拟实际流域可以提供水文变量的时空分布细节，以此产生概念模型检验的系统信息。选用HydroGeosphere模型和浙江和睦桥流域试验场来进行这项工作，结合野外观测、采样和室内土壤水力特性分析，以及数值模拟得到该流域地表及地下的水文参量多维时空分布，进而用于分析以新安江模型为代表的概念水文模型，并检验其主要近似假定在不同水文、地理、及气象条件下的适用性。运用这种方法可以避免观测资料信息量不足的问题，减少分析中的不确定性，解释水文模拟方法的物理机制，以促进水文模拟方法的进一步发展。

目前通用的流域水文模型以概念模型为主，它们均是通过一定的假定及简化来近似真实水文过程。本研究结合野外流域观测数据，使用基于数学物理方法的动力学模型来检验概念模型基本假定的合理性。运用动力学模型来模拟实际流域可以提供水文变量的时空分布细节，以此产生概念模型检验的系统信息。本研究选用HydroGeosphere模型和新安江概念模型，以江苏宜兴梅林实验小流域为对象，结合野外观测、采样和室内土壤水力特性分析，以及数值模拟得到该流域地表及地下的耦合水文过程，并用于分析概念水文模型对耦合产流过程的模拟效果，检验其主要近似假定的适用性。（1）根据梅林流域地理、地质、植被、土壤等基本数据，进行流域描述，运用HydroGeosphere划分网格并建立地表地下耦合水文模型。在流域选取数场代表性洪水过程，率定HydroGeosphere模型参数并应用该模型模拟水文过程。通过模拟获取详细的入渗、蒸发、产流、土壤水分、地下水位等重要水文变量在流域空间的三维分布及产流过程中的时间变化。同时，本研究对历史的观测数据进行详细分析，开展了流域野外原位观测和近地表的水文地质勘查实验，获取了完整的耦合模拟参数集合。建立了典型流域的精细化模型分布式耦合系统和与之平行的概念水文模型系统。运用经典新安江概念模型系统，并针对蓄水容量曲线概化流域内土壤缺水的时空变化，进行了模拟评估。通过对比分析，蓄水容量曲线的率定和精度评估可以配合高精度的耦合模拟近似调整，从而实现低运算效率但高精度的分布式耦合模拟概化到高效率运算的概念水文模型系统。结果表明蓄水容量曲线的率定和精度评估可以配合高精度的耦合模拟近似调整，从而实现低运算效率但高精度的分布式耦合模拟概化到高效率运算的概念水文模型系统。概念模型对敏感的变化饱和度区域响应积极，而对不满足蓄满产流特征的区域响应迟缓但显著依赖概化的土层厚度和土壤下渗速率。该研究有助于我们运用基于物理的分布式模型来研究改进概念性模型参数，进一步提高概念模型的精度和适用性。