瞄准无资料地区流域水文模拟这一国际前沿和热点问题。以完善无资料地区水文模型参数估计方法和径流模拟不确定性评估体系为总目标。选择海河流域的典型子流域为研究对象。围绕流域特征与水文模型参数的物理联系，参数移植误差对径流模拟不确定性的可能影响这两个关键科学问题。以可变下渗容量模型为工具，从历史观测资料分析入手，采用实地调查、统计分析、数值试验和模拟等多种手段相结合的方法，开展四个方面的研究：（1）根据土壤水运动机理和水力学原理，研究基于流域特征直接计算物理意义较强的水文模型参数方法；（2）利用相似流域法，建立模型参数的移植技术；（3）通过矩法和适线法，分析参数移植误差的概率统计特征；（4）由集合预报方法，定量评估无资料地区径流模拟的不确定性。研究成果不仅能够促进水文学、气候学、地貌学等多学科交叉融合与发展，而且在某种程度上可以完善水文模拟技术，对流域的水资源预测、规划和管理等具有重要的科学意义。

Predictions in Ungauged Basins has become a hot issue for hydrologists over the world. The overall object of the project is to estimate the model parameters and to assess the uncertainty of streamflow simulation in the ungauged basins. The typical sub-catchments in the Hai River basins are taken as the study areas. The two key scientific problems of the project are: the physical relationship between catchment characteristics and model parameters, and the impact of the error of parameters regionalization on the uncertainty of streamflow simulation. Based on the Variable Infiltration Capacity model, using integrated approaches of observed data analysis, field investigation, statistics-based analysis, numerical experiment and simulation, etc, the specific research targets of the project are as follows: 1) based on the mechanism of soil water moving and principle of hydraulics, to construct a framework for estimation of model parameters with obvious physical means using the catchment characteristics; 2) to study the model parameters regionalization approach, using the similarity-based methodology; 3) using moments method and curve fitting methodology, to analyze the statistical characters of the errors of parameters regionalization; 4) to assess the uncertainty of streamflow simulation in the ungauged basins, using the ensemble prediction method. The expected achievements of the project will not only rich the knowledge of hydrology, climatology & geomorphology, and improve the hydrologic simulation technology, but also be of significance for water resources prediction, planning & management.