【作者】 史海匀；

【导师】 王光谦；

【作者基本信息】 清华大学 ， 水利工程， 2013， 博士

【摘要】 流域模拟是研究水沙自然规律、解决水利工程问题和提高流域管理水平的主要手段，也是数字流域建设工作的核心和基础。分布式流域模型作为流域模拟的最有效工具之一，在研究人类活动对流域水沙过程的影响等热点和难点问题时发挥了重要作用，但仍需研究提高模拟精度的方法。本文围绕清华大学数字流域模型开展工作，着眼于蒸发能力和降雨这两个基本输入变量，建立了适用于地势陡峻、测站稀疏地区的流域水文信息空间分布计算方法；同时，定量研究了人类活动对流域水沙过程的影响。主要研究成果如下：本文建立了空间分布式蒸发能力计算方法，可为数字流域模型提供更准确的蒸发能力输入。该法由新的修正道尔顿模型和气象要素空间分布计算方法两部分组成：一是提出了用于计算单点蒸发能力的基于水-气温差和气温修正的道尔顿模型；二是考虑地形对气象要素的影响，结合距离权重反比法，建立了利用有限气象站数据计算气象要素空间分布的方法。该法可为计算地势陡峻、测站稀疏地区的蒸发能力空间分布提供参考方法。本文建立了空间分布式降雨计算方法，可为数字流域模型提供更准确的降雨输入。考虑地形对降雨的影响，提出了利用数字高程模型数据对卫星栅格数据进行空间降尺度的方法；考虑降雨的有效影响距离，结合距离权重反比法，提出了基于点（雨量站）面（卫星栅格）降雨数据融合技术的降雨空间分布计算方法。该法结合了不同来源不同空间尺度降雨数据各自的优点，可为计算地势陡峻、测站稀疏地区的降雨空间分布提供参考方法。经检验，上述流域水文信息空间分布计算方法能够在一定程度上提高流域模拟精度。然而，在某些土地利用变化可观的地区，淤地坝等水利水保工程的作用不容忽视。本文定量模拟了以淤地坝为代表的人类活动对流域水沙过程的影响：分析了流域水沙变化特征及其原因，归纳了不同类型的水沙年景；给出了淤地坝的数量及其空间分布，建立了淤地坝与数字河网的一一对应关系以及淤地坝之间的拓扑关系；考虑淤地坝上游来水被全部拦蓄的情形，给出了淤地坝的最大作用比例；分析了现有淤地坝建设情况与降雨空间分布之间的关系，可为今后的水利水保工程建设决策提供数据支持。更多还原

【Abstract】 Watershed simulation is one of the major approaches for studying the natural lawsof water and sediment, solving the practical problems of hydraulic engineering, andraising the level of watershed management. And it is also the core and foundation ofdigital watershed. As one of the most important tools for watershed simulation,distributed watershed models have played a major role in the studies of the key anddifficult issues (e.g., the human impact on the processes of runoff and sediment).However, it is still important and necessary to develop methods for improving theaccuracy of watershed simulation. Based on the Digital Watershed Model (DWM), thisstudy developed the new methods for computing the spatially distributed potentialevaporation (PE) and rainfall; and meanwhile, this study quantitatively researched thehuman impact on the processes of runoff and sediment.A new method for computing the spatially distributed PE, including the modifiedDalton model and the functions for extending meteorological variables, was proposed,which would be useful to provide the more accurate PE inputs for the DWM. First, inorder to compute the PE for a single point, the Dalton model was modified by includingthe influences of the related meteorological variables. Second, through analyzing theimpacts of elevation on the related meteorological variables, the functions for extendingthe meteorological data recorded at a station to any given altitude were developed; andthe inverse distance weighting (IDW) method was applied to integrate the extendedmeteorological variables. The new method would be valuable for computing the spatialdistribution of the PE over regions with steep terrain and sparse meteorological stations.A new method for computing the spatially distributed rainfall through merging theraingauge measurements and the satellite observations was proposed, which would beuseful to provide the more accurate rainfall inputs for the DWM. Considering thetopographic influence on rainfall, a method for the satellite observations downscaling byusing the Digital Elevation Model (DEM) data was developed. Considering the effectiveinfluence radius of a rain, the above two rainfall data were merged by using the IDWmethod. The new method could integrate the advantages of the two rainfall data and would be valuable for computing the spatial distribution of rainfall over regions withsteep terrain and sparse meteorological stations.The methods for computing the spatially distributed PE and rainfall were proved tobe helpful to improve the accuracy of watershed simulation. However, in some regionswith considerable land use change, the impact of soil and water conservation measures(e.g., check dams and reservoirs) could not be ignored. And therefore, this studyquantitatively analyzed and modeled the human impact (e.g., check dams) on theprocesses of runoff and sediment. First, change characteristics of the processes of runoffand sediment as well as the causes were analyzed, and periods of natural state anddisturbed state were defined. Second, the amount and spatial distribution of check damswere given, and the topological relationships between check dams and river reacheswere established. Third, the maximum impact of check dams was evaluated, consideringthe situation that water from upstream was completely intercepted by check dams.Fourth, the relationship between check dam construction and the spatial distribution ofrainfall was analyzed, which would be useful for the decision making of the future soiland water conservation measures in such regions.更多还原