In this study , we demonstrate a technique using the multi - temporal c band hh polarized radarsat scansar data to estimate the relative soil moisture change . the experiment data from sgp97 covered a whole range of vegetation growing season and different type agriculture fields 研究证明，星载合成孔径雷达( sar )得到的地表后向散射系数与地表介电常数有直接相关关系，从而能够在水文模型要求的精度范围内有效提取地表土壤水分信息。
On the platform of digital basin derived from raster dem data , - a grid - based hydrological model and a subcatchment - based hydrological model were used to study the effects of spatial variability on runoff process on such aspects as precipitation , model parameters and soil evaporation 在构建的数字流域平台基础上，建立分别基于子流域离散和栅格离散的数字水文模型，从而分析研究降水、模型参数和土壤蒸发的空间不均匀性对模拟水文过程的影响。
The objectives of this study are : ( 1 ) collect the basis data about soil physical properties , soil moisture , infiltration and evapotranspiration in the catchment scale for developing a catchment hydrological model , based on the dtm , ( 2 ) provide the hydrological information in the catchment scale for developing agricultural production , vegetation rehabilitation , and reasonable land using in this region . the main conclusions drawn from this study are : ( 1 ) the soil physical properties , including bulk density , saturated soil moisture , field capacity , and wilting moisture , were measured at 56 plots across the catchment 为此，本文以黄土高原沟壑区典型小流域?王东沟为研究对象，通过大量的野外测定和室内分析，系统研究了流域土壤容重、土壤饱和含水量、田间持水量、萎蔫湿度、土壤入渗性能、土壤含水量和蒸散量的空间变异性，以期为该区农业生产、植被恢复和土地合理利用等提供科学的依据，同时为建立基于数字高程模型( dtm )为基础的流域水文模型积累基础资料。
Abstract : digital basinis made from digital elevation model considering spatial variability within a catchment . on the basis of digital basin , the digital approach to describing hydrological processes within a catchment is investigated . digital hydrological model is regarded as a modern physically - based modeling technique that includes a large amount of information . the case study on the shiguanhe catchment in the huaihe river basin , intensified observation field of gewex asian monsoon experiment project , has shown that the digital mode lperforms very well not only in simulating runoff processes at any specific site , but also in simulating spatial distribution and temporal variation of hydrological elements and state variable ( especially soil moisture ) , if compared with traditional hydrological models . that provides solid foundation for full use of now available observation in formation and in - depth mining of hydrological data 文摘:考虑流域下垫面空间变异性,基于数字高程模型构建了数字流域,并在此基础上对描述流域水文物理过程的数字方法进行了探讨.文章认为,数字水文模型是一种有物理基础的包含大容量信息的现代模拟技术.史灌河流域实例研究表明,数字水文模型可以十分方便地输出水文要素和状态变量的空间分布与时间序列,这对充分利用现有观测信息进行水文信息的深层挖掘创造了条件
The present study investigates the problems cause by the model structure in the automatic calibration of conceptual hydrologic models and the use of hydrological response units ( hrus ) in chms to improve the model performance via integrated gis approach while keeping the number of basic model parameters and the model structure as original 本文对概念性水文模型自动参数率定中模型结构方面以及水文响应单位( hru )的利用方面导致的问题进行了调查，在保持模型原有结构和基本模型参数的基础上通过集成gis提高了模型的精度。
Developing and establishing macro - scale distributed hydrological model are required in order to make certain the regional water and energy cycle , study and resolve the hydrology and water resources problems under the changing environment according to the climatic prediction of gcm . as a branch of hydrologic cycle , land - surface hydrologic processes are nearly relative to atmospheric circle by water and energy exchange between land - surface and atmosphere 为了确定大尺度区域水文循环及能量收支、能够根据gcm给出的气候预测，研究和解决变化环境中的水文水资源问题，评估和监测大流域的径流过程和水资源量的动态变化规律，需要研制和建立大尺度分布式水文模型。
Traditionally , the saturated zone is modeled as a simple lumped continuity equation : , dsitqsdt where t is time , s is the total storage in the reservoir , i is the spatially integrated volume of incoming wa - ter , and q is the discharge subsurface runoff which only depends on the total storage s . this kind of subsurface runoff model has many different parame - terizations 10 12 , however it has a very common char - acteristic that the subsurface runoff is just a sin - gle - valued storage - discharge function 对于大尺度水文模型而言,目前常常采用的是集总式的地下径流机制,其连续性方程一般可表示为d , dsitqst ? 1这里t是时间, s表示整个流域潜水面土壤层的饱和区域总的水分储存量, i t表示t时刻土壤的非饱和区域向整个潜水面的水分补充量, q s表示仅依赖于水分储存量s的地下径流量量
It is found that the automatic detection of drainage networks from digital elevation models is affected by flat areas and closed depressions . a variety of methods have been proposed to treat these two features , but it can be seen that the flat areas and closed depressions are processed only after they have been created , so that many spurious and parallel drainage courses are generated 数字高程模型( dem )已在分布式流域水文模型中得到了越来越广泛的应用，但dem中的闭合洼地和平坦区域影响着流域河网的自动提取。目前已提出好多方法来处理这两种地形，但均针对已经形成的dem单元网格进行处理，结果往往生成伪河道及平行河道。
Based on a large number of the papers published in journals of china from 2002 to 2005 and the important national projects and project research reports of the national natural science foundation of china in the recent years , this paper reviews the main study results and progressions in the china in the elements of hydrologic cycle such as precipitation , evapotranspiration and runoff , water balance , stream sediment , lake , swamp , wetland , glacier , frozen earth , and groundwater and subsurface water 摘要根据2002 - 2005年中国公开发表的关于水科学研究的论文及国家重大攻关项目和国家自然科学基金项目的科研报告，综述了近年来中国在水文循环诸要素如降水、径流、蒸发，水文模型，河流与泥沙、湖泊、沼泽与湿地、冰川与冻土以及地下水与土壤水等方面研究取得的主要成果和进展。
It is assumed that model parameters calibrated from measured precipitation - runoff data in a specific period , reflect the situation of land surface and the human activity in that period . firstly , daily data of precipitation , pan evaporation , and discharge in 1960 ' s are used to calibrate the parameters of the xin ' anjiang model . then the parameters calibrated are applied to the computation of daily discharge from 1950 ' s through 1990 ' s , in which daily measured data of precipitation and pan evaporation are taken as the input of the xin ' anjiang model 这种径流过程代表下垫面和人类活动水准不变情况下气候波动对径流的影响，然后利用计算的长系列径流过程与实测径流过程对照，其差别反映下垫面的自然变化过程是十分缓慢的，可以忽略，因此这种差别主要代表了人类活动的影响，从前后期率定水文模型所得参数的差别及参数所代表的物理意义来分析下垫面及人类活动的变化，从而将气候波动和人类活动对地表水资源影响程度定量分解出来。
