新安江模型参数线性化率定研究

包为民教授提出了非线性函数参数的线性化率定方法,解决了以误差平方和为目标函数求解非线性函数参数增加不相关的局部优值问题。为此,研究将参数线性化率定方法应用于新安江模型,并通过理想流域和实际流域验证了该方法的合理性和高效性。选取湖北乌溪沟流域43场洪水对次洪8个敏感参数同时进行线性化率定,各参数取不同的初始值均可以较快地收敛到稳定的最优值。31场洪水参与模拟,全部合格;12场洪水参与检验,全部合格。次洪模拟的合格率达到100%,确定性系数为0.923,预报等级为甲级。     

函数曲面参数率定方法在SAC 模型中的应用

传统优化算法和现代优化算法均是基于目标函数曲面寻求优值,而大多数参数率定方法的目标函数均为误差平方和。直观看来,基于误差平方和的目标函数曲面往往较参数函数曲面更为复杂。此外,这些算法常常无法证明寻得的优值是全局优值,而且计算过程较复杂,效率较低。鉴于此,提出函数曲面参数率定方法,并应用于SAC理想模型和实际模型的参数率定。首先,通过理想模型验证了该方法的可行性;其次,通过东张流域13年日资料和13场洪水验证了该方法的实际应用效果。结果表明,该方法在实际应用中是可行的、效率与精度皆较高,是一种有效的参数优选方法。     

系统微分响应参数率定方法在建阳流域SWAT模型中的应用

利用基于系统微分响应理论的参数率定方法率定闽江建阳流域SWAT模型,通过流域1992—2000年日资料验证了该方法的实际应用效果,采用纳什效率系数(NSE)、偏差百分比(PBIAS)和相关系数r作为评价指标对率定后的SWAT模型模拟精度进行评价,并与传统利用SUFI-2方法率定得到的SWAT模型模拟结果进行对比分析。结果表明：系统微分响应方法率定的参数在建阳流域的日径流模拟中表现较好,率定期和检验期NSE均为0.65以上,径流量PBIAS在5%以内,r在0.65以上;利用系统微分响应率定参数方法率定SWAT模型参数在实际应用中可行,且效率与精度均高于传统的SUFI-2方法。     

SWAT模型参数敏感性分析与自动率定的重要性研究——以玛纳斯河径流模拟为例

介绍了SWAT2005模型参数敏感性分析和自动率定模块的原理,并在新疆玛纳斯河流域中进行应用,通过敏感性分析及参数率定前后的结果对比,证明该模块对模型应用的重要性。根据LH-OAT敏感性分析法,辨析出影响玛纳斯河流域径流模拟结果精度的主要参数因子:积雪温度滞后因子(Timp)和基流回退系数(Alpha_Bf)。根据SCE参数自动率定法,确定出对径流模拟结果影响较大的11个参数值,并采用连续5年的实测日径流数据对模型进行了验证。结果表明:模型对日流量模拟的相对误差在模型校准期和验证期均小于20%,相关系数R2高于0.8,Nash-Suttcliffe系数Ens高于0.7,SWAT模型在玛纳斯河流域产流的模拟结果良好,值得进一步推广。     

基于BP神经网络的HEC-RAS二维模型糙率参数自动率定

水面宽阔河段、洪泛区和潮汐河口段的水文及水动力学计算模拟多采用二维模型,然而因模型复杂的非线性映射关系常导致参数率定效率和精度不高,甚至出现"异参同效"问题。为此,提出一种应用BP神经网络自动率定二维模型糙率参数的方法。以海南昌化江入海口段为计算实例进行数值检验,结果表明:编写的Python程序能够准确率定HEC-RAS二维模型实例各糙率分区的糙率参数,各糙率分区的率定糙率值均在参数取值范围内,且均在观测糙率值±0.011内,未出现"异参同效"现象;水位率定计算误差满足设定允许误差要求,设定允许误差0.20 m、0.15 m和0.10 m的平均率定计算误差小于0.10 m,设定允许误差0.05 m的平均率定计算误差接近0 m;设定允许误差为0.15 m时,率定程序的运算效率最高。选用海南201409号台风"威马逊"时期的昌化江实测资料进行验证,证明该方法有效可靠,能够实现HEC-RAS软件二维模型糙率率定功能,可推广应用于其他模型参数率定。     

HYPE模型在成屏一级水库的适用性研究

水文模型是模拟水库入库流量的重要工具之一。以浙江省遂昌县成屏一级水库为研究对象,基于LHOAT方法、DE方法和HYPE模型,通过参数敏感性分析、参数率定和误差分析,评估了HYPE模型对成屏一级水库入库流量模拟的适用性。结果表明:HYPE模型中极敏感的参数为cevp,较敏感的参数为pcluse、cevpcorr、rrcscorr、rrcs1; HYPE模型在率定期的纳什效率系数(NSE)为0. 87,在验证期的纳什效率系数(NSE)为0. 83,这表明HYPE模型具备在长序列日尺度水文模拟的能力; HYPE模型在洪峰模拟上模拟值低于实测值,原因可能是输入数据的精确性不足以及率定的模型参数并不能较好地反映出暴雨过程中的流域特征;对暴雨情况采用新的参数进行流域特征刻画,模型模拟效果更好。     

新安江模型系统响应参数优化方法在邵武流域的应用

针对现有参数率定方法在目标函数曲面上寻优存在率定结果不稳定、收敛性能差、效率低、找不到全局优值等问题,利用因变量增量与参数变化之间存在的系统响应关系构建了系统响应参数率定方法。采用邵武流域的实测资料和新安江模型对该方法进行了应用检验。结果表明系统响应参数率定方法可以找到参数全局优值,不受初值影响,率定结果稳定,效率较高。因此说明系统响应参数率定方法是一种可行有效的参数优选方法,对其他模型参数优选具有一定的借鉴意义。     

应用分布式水文模型优化黑龙港及运东平原农田灌溉制度Ⅰ：模型参数的率定验证

为了应用分布式水文模型优化该地区的农田灌溉制度,本文首先运用洗牌复形演化(SCE-UA)算法在曲周和吴桥两个试验站对分布式水文模型(SWAT)中的作物参数进行了率定,接着以遥感监测实际蒸散(ETa)数据为目标,在该区域应用拉丁超立方-单次单因素(LH-OAT)方法对SWAT模型中的参数进行敏感性分析,选出了对ETa最敏感的参数,用序贯不确定性(SUFI-2)算法优化出一套参数范围,最后对冬小麦-夏玉米轮作体系产量的长期模拟结果进行了验证。这些参数率定和模拟验证的结果为进一步深入研究该地区节水农业中的水分生产函数和优化灌溉制度奠定了基础。     

新安江模型在汤旺河流域洪水预报中的应用

介绍了新安江模型发展历程,以及模型结构和原理,系统说明了模型参数类型和模型优化方法,通过实例运用三水源新安江模型采用分层分析的方法对模型的参数进行率定,对汤旺河流域日流量过程进行了模拟,模拟分析表明,新安江模型在东北地区洪水预报中还是能很好地应用。     

GIS在三峡流域水文模拟中的应用

本文在三峡区间6个小流域上由人工率定了新安江模型参数，在地理信息系统平台上推求了流域地理地貌特征值。采用相关分析的方法，对自由水蓄水容量SM、地下水出流系数KG、壤中流出流系数KI、马斯京根法汇流系数X等模型参数和下垫面地形、地质、植被等特征值建立了相关关系。由相关关系和特征值采用反演的方法推求上述参数的反演值。经小流域模拟验证，相关关系是可靠的，在实际降雨径流模拟中能达到一定的精度。因此，由特征值反演参数的方法可移用于无资料地区，解决此类地区模型参数的率定问题。本文提出的方法已应用于长江三峡区间实时洪水预报中。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…