山区水资源主要来自降雨、积雪、冰川融水产生的径流。无论以何种产流为主的流域，基流都是其河川径流的重要组成部分，是枯水季节径流的主要来源。开展雨-雪-冰不同产流下河川基流过程模拟研究对流域水资源管理和河流健康维护具有重要意义。不同产流下可靠的基流分割是面临的关键问题。本项研究创新地引入具有物理意义、含有较少参数、参数化简便的非线性库理论，构建基流过程模拟方程，发展不同产流下分布式水文模型中河川基流过程模拟方法；将源于降雨径流流域的数字滤波法，拓展到雪-冰产流流域，建立适用于雪-冰产流流域的数字滤波基流分割方程；利用改进的模型，在干旱-高寒山区以雪冰产流为主的玛纳斯河流域和半湿润-湿润区以降雨产流为主的沙颍河流域，检验和完善理论研究成果，研究雨-雪-冰不同产流下河川基流过程的季节、年际变化特征及控制机理，量化地下水对河川径流的贡献，揭示干旱-高寒山区和半湿润-湿润区河川基流过程特征的异同。

The alpine mountain areas are the origins of runoff. Runoff in most of the rivers in the mountain areas, is mainly from melt-waters of snowpacks and glaciers, and/ or from rainfall in alpine mountain areas. Base flow is the main component of runoff, particularly during low flow periods, no matter what types of runoff generation. To carry out the simulation of base flow process for different runoff generation from rainfall, snow and/or glacier, has a significant meaning for the basin water resources management and the river health maintenance. However, reliable separation of base flow under different hydrological conditions is the key problem. The nonlinear aquifer storage-discharge approach will be used in the study, which has a physical meaning with only two parameters and is easy to parameterize. The parameters in the exponential function that describes the aquifer storage-discharge relationship could be optimized independent of the SWAT model by using observed streamflow data during recession periods. The functions of base flow calculation will be constructed based on the aquifer storage-discharge relationship and the methods of base flow simulation in the distributed hydrological model under different hydrological conditions will be developed. Moreover, the equations of the digital filter used for base flow separation applicable for the basins dominated by snowmelt and glacier melt will be developed, which is based in signal analysis and processing for rainfall-dominated basins. By collecting the data, the improved model will be established for the typical catchments in the Manas River Basin (dominated by snow/ glacier melt) in the arid-cold mountain areas, Shaying River Basin (dominated by rainfall) in the semi humid-humid areas, and will be calibrated, validated and assessed. Based on the simulation by the improved model, the spatial and temporal variations in base flow will be analyzed, the mechanism will be discussed, the contribution of base flow to runoff will be quantified, and the similarities and differences of the base flow characteristics between the arid-cold mountain areas and semi humid-humid areas will be revealed.