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391.
392.
The spatial distribution of soil physical properties is essential for modeling and understanding hydrological processes. In this study, the different spatial information (the conventional soil types map-based spatial information (STMB) versus refined spatial information map (RSIM)) of soil physical properties, including field capacity, soil porosity and saturated hydraulic conductivity are used respectively as input data for Water Flow Model for Lake Catchment (WATLAC) to determine their effectiveness in simulating hydrological processes and to expound the effects on model performance in terms of estimating groundwater recharge, soil evaporation, runoff generation as well as partitioning of surface and subsurface water flow. The results show that: 1) the simulated stream flow hydrographs based on the STMB and RSIM soil data reproduce the observed hydrographs well. There is no significant increase in model accuracy as more precise soil physical properties information being used, but WATLAC model using the RSIM soil data could predict more runoff volume and reduce the relative runoff depth errors; 2) the groundwater recharges have a consistent trend for both cases, while the STMB soil data tend to produce higher groundwater recharges than the RSIM soil data. In addition, the spatial distribution of annual groundwater recharge is significantly affected by the spatial distribution of soil physical properties; 3) the soil evaporation simulated using the STMB and RSIM soil data are similar to each other, and the spatial distribution patterns are also insensitive to the spatial information of soil physical properties; and 4) although the different spatial information of soil physical properties does not cause apparent difference in overall stream flow, the partitioning of surface and subsurface water flow is distinct. The implications of this study are that the refined spatial information of soil physical properties does not necessarily contribute to a more accurate prediction of stream flow, and the selection of appropriate soil physical property data needs to consider the scale of watersheds and the level of accuracy required.  相似文献   
393.
淮河流域极端径流的时空变化规律及统计模拟   总被引:9,自引:0,他引:9  
以淮河流域蚌埠闸以上20 个水文站点1956-2010 年日径流量观测数据资料为基础,采用游程检验、趋势检验和Mann-Kendall 检验法分析年最大日径流量的变化规律。分别采用年最大值法(annual maximum,AM) 和超门限峰值法(peaks over threshold,POT) 抽取径流序列样本, 运用广义极值分布(generalized extreme value distribution,GEV) 和广义帕累托分布(generalized Pareto distribution,GPD) 两种极值统计模型对规范化样本进行拟合,分析淮河流域极端径流的时空变化规律。研究表明:1956-2010 年,淮河流域蚌埠闸以上的研究站点中,10 个站点的年最大日径流量有减少的趋势,另外10 个站点有不显著的增加趋势。极端径流事件大多发生在20 世纪60、70 年代,且以汛期居多。淮河流域的极端径流主要来自淮河干流、淮南山区和伏牛山区。使用Kolmogorov-Smirnov (K-S) 法检验发现,GEV和GPD分布分别能较好的拟合AM和POT序列。采用百分位阈值法、平均超出量函数图法和超定量洪峰法三种方法选取阈值,对于淮河流域的极端径流事件模拟而言,百分位阈值法较好。  相似文献   
394.
水文模型参数敏感性快速定量评估的RSMSobol方法   总被引:4,自引:1,他引:3  
水文模型参数敏感性分析是模型不确定性量化研究的重要环节,其可以有效识别关键参数,减少模型率定的不确定性,提高模型优化效率。然而如何快速有效地定量评估参数敏感性已成为当前大尺度分布式水文模型优化的瓶颈。针对传统的全局定量敏感性分析方法在多参数复杂水文模型的不足,本文采用基于统计学习理论的支持向量机(SVM) 建立非参数响应曲面(称为代理模型),再结合基于方差的Sobol 方法,建立了基于响应曲面方法的Sobol 定量全局敏感性分析方法(RSMSobol 方法),实现复杂模型系统参数敏感性的快速定量化评估。本文选用淮河流域的日尺度分布式时变增益水文模型进行实例研究,采用水量平衡系数(WB),Nash-Sutcliffe 效率系数(NS) 和相关系数(RC) 三个目标函数综合评价模拟效果。研究结果显示RSMSobol方法在实现定量全局敏感性分析的同时降低了模型运行时耗,提高了模型评估效率,且与传统定量方法Sobol 方法具有同样的评估效果。该方法的有效应用为大型复杂水文动力模拟系统的参数定量化敏感性评价提供了参考,为模型参数进一步优化提供了可靠依据。  相似文献   
395.
Technological and methodological advances have facilitated tremendous growth in hydrology during the last century; however, there are also concerns that these advances indirectly contribute to additional problems in our research. An insight into hydrologic literature reveals our tendency to develop more complex models than perhaps needed, and our increasing emphasis on individual mathematical techniques rather than general hydrologic issues. Some recent studies of diverse forms have suggested that simplification in modeling and development of a common framework may help alleviate these problems. The present study is intended to bring such studies together towards a more coherent approach to research in catchment hydrology. This is done by highlighting the need for model simplification and generalization and proposing some potential directions for achieving such. Through a discussion of difficulties in data measurements, the need for moving beyond the notion of “modeling everything” to the notion of “capturing the essential features” is explained; the concept of dominant processes in model simplification and the utility of integration of concepts for modeling improvement are discussed. Formulation of a catchment classification framework is advocated as a possible means for a common framework in hydrology, and the role of dominant processes in this formulation is presented; the problems due to adoption of different modeling terminologies are highlighted and potential ways to overcome such are also discussed.  相似文献   
396.
以"淮河流域重点平原洼地治理工程外资项目"为对象,综合分析了流域内地理气候、经济社会、河流水系及防洪体系的相互关系与演变特征。在气候变化影响下,流域3种类型的洪水中,由持续一两个月的长历时降水形成的量大但不集中的洪水,对平原洼地农业发展及治理工程效益的影响最为显著。在此基础上,对气候变化可能造成的影响进行了半定量分析,并提出了增强排涝能力与提高自适应能力并举的应对方案。  相似文献   
397.
Land use and in-stream transformation exert great influence on concentrations and loads of phosphorus (P) in rivers. We aimed to display differences in the courses of total P (TP) and soluble reactive P (SRP) concentrations and loads in six medium-sized to large rivers in the central region of Germany, and to identify the reasons for different long-term trends. Therefore, we applied multivariate statistics to 10-year-time series (1994–2003) of TP, SRP, discharge (Q), water temperature (T), pH, dissolved organic carbon (DOC), total organic carbon (TOC), dissolved oxygen (DO), total iron (Fe), and total manganese (Mn). Statistical results were related to land use in the catchments of the rivers. TP concentrations ranged between 0.02 and 0.78 mg l−1, and SRP concentrations ranged between 0.01 and 0.44 mg l−1. Q correlated negatively with TP and SRP concentrations over the entire year. Furthermore, Fe correlated significantly and positively to TP and SRP and therefore, ferric hydroxides likely were the major P sorption sites. DOC showed significant positive correlation to SRP particularly in spring, indicating manure exposure in early spring as a major source of both, DOC and SRP. Significant negative correlations between DO and SRP in summer hint at internal P loading in rivers or in flushed lakes. Different forms of land use were the reasons of enhanced or retarded recovering from previous increases in P concentrations. High portions of arable land within some of the catchments impeded the process of decreases since 1996 because of remaining high-diffuse emissions from fertilized soils. Agricultural practices, exposing fertilizer to soils within the river catchments and high Q in early spring caused high TP and SRP loads to downstream systems, and evoked risks for downstream river reaches.  相似文献   
398.
淮河流域典型地面水热通量的观测分析   总被引:17,自引:1,他引:16  
根据1998年淮河流域能量和水循环试验加密观测(HUBEX-IOP)获得的资料,用三种微气象方法计算该地区的感热通量和潜热通量状况,比较了不同方法所估算结果的异同,并以梯度法的资料为主分析了其变化特征.结果表明:(1)梯度法估算的潜热通量与用波文比-能量平衡方法的估算值比较接近,与涡度相关方法估算的值之间有一定的差异.(2)感热通量和波文比在梅雨(6月28日~7月4日)前较大,在后期较小.大部分辐射能用于地面蒸发.  相似文献   
399.
HUBEX期间暴雨模拟研究   总被引:2,自引:0,他引:2  
利用中尺度数值预报模式MM4和淮河流域能量与水循环试验(HUBEX)外场观测资料,对1998和1999两年HUBEX期间的暴雨进行数值模拟.同时,将处理后的云图资料输入到MM4中,改变水汽场条件进行数值模拟,作为敏感试验,并且与不用云图资料的控制试验作比较.两种模拟结果与地面试验区的雨量资料对比分析表明,MM4对夏季淮河流域的强降水有较好的预报能力.  相似文献   
400.
纳木错流域近30年来湖泊-冰川变化对气候的响应   总被引:20,自引:1,他引:19  
Based upon the 1970 aero-photo topographic map, and TM/ETM satellite images taken in 1991 and 2000, the authors artificially interpreted boundaries of lake and glaciers in Nam Co Catchment, and quantified lake-glacier area variations in different stages by "inte-grated method" with the support of GIS. Results show that from 1970 to 2000, lake area in-creased from 1942.34 km2 to 1979.79 km2 at a rate of 1.27 km2/a, while glacier area de-creased from 167.62 km2 to 141.88 km2 at a rate of 0.86 km2/a. The increasing rate of lake in 1991-2000 was 1.76 km2/a that was faster than 1.03 km2/a in 1970-1991, while in the same period of time, the shrinking rates of glaciers were 0.97 km2/a and 0.80 km2/a respectively.Important factors, relevant to lake and glacier response to the climate, such as air tempera-ture, precipitation, potential evapotranspiration and their values in warm and cold seasons,were discussed. The result suggests that temperature increasing is the main reason for the accelerated melting of glaciers. Lake expansion is mainly induced by the increase of the gla-cier melting water, increase of precipitation and obvious decrease of potential evapotranspi-ration. Precipitation, evaporation and their linkages with lake enlargement on regional scale need to be thoroughly studied under the background of global warming and glacier retreating.  相似文献   
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