一种改进遗传算法在降雨径流模型中的应用

针对传统的自动优选方法、罗森布瑞克法和单纯形法对初值敏感性强,易陷入局部极值和标准二进制遗传算法精度较低的不足,从动态改变参数初值取值范围的角度提出了一种改进的遗传算法,用以解决降雨径流模型中的参数率定问题。以三水源新安江模型为例并结合密赛流域7年的降雨径流实测资料,用该方法得到了较优解,其率定期参数率定结果达到了《水文情报预报规范》的甲级标准。     

半干旱地区提高水文预报精度

1前言水文预报精度问题，是洪水预报成功与失败的关键。水文工作者为提高水文预报精度作出了不懈的努力，包括建立洪水预报模型，优化率定参数，提高模拟水平，这无疑是正确的。迄今为止，水文预报模型已达数十种，但在半干旱地区的海河流域，面对国内外众多的模型，适合于此地     

利用计算机技术解决率定水文预报模型参数所需历史资料问题

利用洪水预报模型进行洪水预报,因其下垫条件的不同,其应用好坏也不同。所以模型的应用好坏,关键在于能否根据本地的实际情况,通过历史资料率定与之相应的模型参数。鉴于目前全国水文系统已经建成统一的水文数据库,因此可以充分利用计算机这一技术手段,并结合现有的水文数据库编制应用软件,解决率定模型参数所需的大量历史水文资料工作难度大的问题。     

飞来峡水利枢纽基于DEM的分布式流域水文预报模型

利用飞来峡水利枢纽建库运行后的水文资料,建立基于DEM的分布式水文预报模型,对参数进行率定,并进行预报模拟。从模拟结果看,模型确定性系数、洪峰相对误差、径流总量相对误差等指标基本在可接受范围内,对大部分场次洪水的预报精度较好,洪峰流量合格率也较好,但整体上对洪峰的模拟值偏低,预报精度有待进一步提高。今后随着资料的不断延长和积累,对参数进行重新率定,其预报结果可应用于预报作业中。     

遗传算法在三水源新安江模型参数率定中的应用研究

遗传算法是一种全局数值优化方法。该文在三水源新安江模型的参数率定问题中,结合遗传算法的基本原理和参数自身的特点,提出了基于遗传算法的参数率定方法,并通过实验确定遗传算法的参数。经过清江流域几次洪水历史资料的实例应用验证,结果表明该方法直观、简便、适用性强,率定的模型参数是合理的,能够提高洪水预报精度。该文所介绍的方案已成功应用于“数字清江”工程洪水预报中。     

基于神经网络与遗传算法的洪水分类预报研究

针对水文模型参数的不确定性,对洪水进行分类预报,不同类型洪水采用不同预报参数,旨在提高洪水预报精度。基于BP神经网络模型,依据分类因子选取原则,选取6项具有代表性的影响因子作为模型输入,可将洪水划分成高、中、低3类。基于遗传算法,对3类洪水进行参数率定,获得3组不同的参数组,最终利用训练好的分类预报模型实现不同类型洪水的变参数预报。以大伙房水库25场历史典型洪水进行实例验证与分析,结果表明:分类预报结果的洪峰误差、峰现误差、确定性系数及典型洪水过程的拟合效果明显优于分类前。经训练后的基于BP神经网络与遗传算法的洪水分类预报模型可较好适用于大伙房水库,结果更贴合实测值,效果整体上优于分类前,方法可行、有效。     

系统水文模型在洮河干流洪水演算中的应用

利用系统水文模型分别对洮河岷县－李家村、岷县－红旗段建模，根据历史洪水资料优选拟合，得出相应的洪水演算模型。并对未参加参数率定的资料进行试报，结果表明：本方法具有较高的预报精度，可用于发布实时洪水预报。     

预报模型的组合及其在韩江流域洪水预报中的应用

简要介绍了几种预报模型原理，结合韩江流域现有水文站点的分布特点及预报需要对预报模型进行组合，并用水文资料率定参数和检验，据此分析论证了其在洪水预报中的应用和作用。     

基于遗传算法的TOPMODEL参数优化

模型参数的确定是模型研制与应用成功与否的关键．一般采用人工经验率定和自动率定两种方法来确定．遗传算法和一般的优化算法不同,它具有全局寻优能力,是一类优秀的非线性函数优化算法．利用遗传算法来进行TOPMODEL参数优化,并和人工率定的计算结果作了简要的对比,明显地显示该方法的优点．采用遗传算法所得到的精度较高,可以类推到其他水文模型的参数优化中去．     

流域洪水实时预报模型研究及应用

根据广西合浦水库流域的水文特征 ,利用分散型新安江三水源模型对合浦水库流域洪水实时预报进行了研究。对流域产汇流模型以及洪水实时预报校正模型的参数进行了率定 ,并将研制的模型应用于实际洪水预报 ,取得较满意的效果     

流域洪水预报系统及其关键问题研究

论述了流域洪水预报系统的主要任务和核心内容,介绍了流域洪水预报系统的结构和主要功能,分析了系统的主要功能模块,将智能算法与传统的水文预报方法相结合,在水文预报模型参数自动率定、实时洪水校正两方面进行了尝试,并建立了相应的模型,经过流域长系列水文资料检验和应用,获得了满意的结果,为实时洪水预报开辟了新的途径。     

基于SCE-UA算法的河网水系水闸调度模拟

建立福州市江北城区内河水系水动力水质耦合模型,利用SCE-UA算法对水闸调度参数进行优化。结果表明,SCE-UA算法可用于水文模型参数的率定和河网水系水闸调度系统优化参数的识别。在待优化的区域单独建模,将生态补水规划模拟计算结果为优化区域提供边界,结果使模型计算时间大大减少。将优化后的参数代入原模型进行检验,效果令人满意。     

长江中游水文情势变化及对鱼类的影响分析

为分析三峡水库蓄水后长江中游河道水文情势变化情况及其对鱼类产卵繁殖的影响,采用水文变化指标体系和变动范围法,对宜昌站水文情势变化进行了定量分析,得出了变化程度较为剧烈的水文参数。通过对照典型鱼类的历史产卵量与历史流量过程,归纳了典型鱼类四大家鱼的生态水文需求,得出了影响鱼类产卵繁殖的主要水文参数。提出了水文情势变化影响鱼类产卵繁殖过程的概念性模型。在分析的基础上,揭示了长江中游水文情势变化对鱼类产卵繁殖的影响。     

基于MapX控件绘制水文数据等值线

采用VB集成MapX控件进行地理信息系统GIS开发的技术,解决了雷达测雨及分布式水文模型计算所得的大量分布式栅格地理数据的处理和显示问题.在地理数据分析中选用一种基于正交网格的等值线算法,并由VB程序实现.将该项技术应用于史灌河流域,并绘制了雷达估测的降雨数据及分布式模型计算所得的水文数据的等值线图,表明将该技术应用于分布式水文模型的数据分析与显示是成功的。     

柏叶口水库洪水预报方案

根据柏叶口水库所在流域特点选择适合的水文模型与产汇流模型,并论述了应如何选定洪水预报方案及如何率定模型的参数。     

Estimation of a Unique Pair of Nash Model Parameters: An Optimization Approach

Water resources planning and management requires hydrologic models to estimate runoff from a catchment. For catchments with limited data, the choice of model and identification of its parameters is very important for development of a direct runoff hydrograph. A method is presented to determine a unique pair of hydrologic parameters of the Nash Model, number of linear cascade (n) and storage coefficient (k), using optimization based on Downhill Simplex technique. In this study physical parameters of the catchment are derived from (SPOT) satellite imageries of the basin using ERDAS software. Four different objective functions of varying complexity are tested to find the best solution. Weighted root mean square error (RMSE) and Model Efficiency (Nash-Sutcliffe coefficient) are used to evaluate the model performance. Using the NASH model, a direct surface runoff hydrograph (DSRH) is developed. Kaha catchment is part of Indus river system and is located in the semi-arid region of Pakistan. This catchment is dominated by hill torrent flows and is used in this work to demonstrate the applicability of the proposed method. Ten randomly selected rainfall-runoff events are used for calibration and five events are used for validation. Model results during validation are very promising with model efficiency exceeding 93% and error in peak discharge under 8%. The sensitivity of the Nash model output in response to variation in hydrologic parameters n and k is also investigated. When evaluating the hydrologic response of large catchments, model output is more sensitive to n as compared to k indicating that the runoff diffusion phenomenon is dominant compared to translation flow effects.     

小流域水文计算样本容量的实例分析

本文根据澧水流域中双枫潭水文站的实测资料,通过水文系列代表性分析,不同样本容量n的各样水文计算统计分析,以及流域产汇流参数分析,发现该站水文系列达到20年时,不同样本容量n的各样本水文计算值都趋于稳定,只在一个极小的范围内摆动,而流域的产汇流参数也不再随n增大而变化。按照水文计算规范,小流域有了这一定年限的水文资料,就能基本满足水文计算的要求了,这一年限就是该小河站的设站年限。     

Sustainable Basin-Scale Water Allocation with Hydrologic State-Dependent Multi-Reservoir Operation Rules

This study extends the PSO-MODSIM model, integrating particle swarm optimization (PSO) algorithm and MODISM river basin decision support system (DSS) to determine optimal basin-scale water allocation, in two aspects. The first is deriving hydrologic state-dependent (conditional) operating rules to better account for drought and high-flow periods, and the second is direct, explicit consideration of sustainability criteria in the model’s formulation to have a better efficiency in basin-scale water allocation. Under conditional operating rules, the operational parameters of reservoir target storage levels and their priority rankings were conditioned on the hydrologic state of the system in a priority-based water allocation scheme. The role of conditional operating rules and policies were evaluated by comparing water shortages associated with objective function values under unconditional and conditional operating rules. Optimal basin-scale water allocation was then evaluated by incorporating reliability, vulnerability, reversibility and equity sustainability indices into the PSO objective function. The extended model was applied for water allocation in the Atrak River Basin, Iran. Results indicated improved distribution of water shortages by about 7.5% using conditional operating rules distinguishing dry, normal and wet hydrologic states. Alternative solutions with nearly identical objective function values were found with sustainability indices included in the model.     

分布式流域水文模型研究中的几个问题

指出数值计算、GIS、雷达测雨和卫星云图等技术的进步为分布式流域水文模型的发展及实际应用提供了条件 .论述分布式流域水文模型的结构有概念性和具有物理基础之分 ,也有耦合式和非耦合式之分 .为了确定分布式流域水文模型的参数 ,对现有几种建立产汇流参数与自然地理因子之间的理论关系的途径进行了初步分析 .     

Energy budget considerations for hydro-climatic impact assessment in Great Lakes watersheds

Given the large share of the water budget contributed by evapotranspiration (ET), accurately estimating ET is critical for hydro-climate change studies. Routinely, hydrologic models use temperature proxy relationships to estimate potential evapotranspiration (PET) when forced using GCM/RCM projections of precipitation and temperature. A limitation of this approach is that the temperature proxy relationships do not account for the conservation of energy needed to estimate ET consistently in climate change scenarios. In particular, PET methods using temperature as a proxy fail to account for the negative feedback of ET on surface temperature. Using several GCM projections and a hydrologic model developed for the Great Lakes basin watersheds, the NOAA Large Basin Runoff Model (LBRM), the importance of maintaining a consistent energy budget in hydrologic and climate models is demonstrated by comparing runoff projections from temperature proxy and energy conservation methods. Differences in hydrologic responses are related to watershed characteristics, hydrologic model parameters and climate variables. It is shown that the temperature proxy approach consistently leads to prediction of relatively large and potentially unrealistic reductions in runoff. Therefore, hydrologic projections adhering to energy conservation principles are recommended for use in climate change impact studies.