五强溪水库近坝区洪水预报方法研究

针对五强溪水库近坝区洪水预报难度大、预报精度难以满足实际需求的现状,基于历史暴雨中心分布与流域产汇流特征划分单元流域,采用三水源新安江模型构建入库洪水预报新方案进行参数率定和历史洪水模拟,并综合剖析了洪水预报误差的主要原因。研究结果表明,构建的洪水预报新方案能够取得较高的洪水预报精度,在2021年实时洪水预报作业中取得了良好的应用效果。流域内水利工程泄洪资料的缺失是目前造成洪量及洪峰模拟误差的主要原因。     

飞来峡水库入库洪水计算模型探讨

在分析北江流域暴雨洪水特性的基础上,针对飞来峡水库流域洪水的特点和复杂性,采用水文学和水力学相结合的方法,构建了飞来峡水库入库洪水计算的耦合模型,整个模型由区间洪水计算的流域水文模型和河网水力学数学模型组成,模型的计算结果表明,洪水模拟与实测过程拟合较好,精度较高.其成果可作为飞来峡水库入库洪水分析和水库动库调洪计算的基础,为水库防洪调度的设计提供依据.在流域洪水模拟的过程中,采用了移用邻近参证流域资料进行水文参数率定和降雨径流模拟,取得了满意的结果,对无资料区间的洪水计算进行了有益的尝试.     

新安江模型与衰减记忆最小二乘法耦合洪水模型的应用

利用新安江模型进行流域产流计算,采用扩散波方程推得的汇流状态方程描述流域汇流过程,由衰减记忆递推最小二乘法实现参数估计实时化,从而使新安江模型与衰减记忆递推最小二乘法耦合,实现洪水实时预报。利用耦合模型对矶头水库76场入库洪水进行模拟,模拟结果表明,耦合模型适合中小水库入库洪水实时预报,预报精度比独立使用新安江模型得到了大大的提高。     

半湿润流域洪水预报实时校正方法比较

为了提高新安江模型在半湿润流域的洪水预报精度,选择K最近邻(KNN)算法、传统的误差自回归(AR)方法、反馈模拟方法3种实时校正方法,以陕西省陈河流域为试验对象进行洪水预报。以洪峰相对误差和纳什效率系数为评价指标,分析对比3种方法的校正效果。结果表明:3种校正方法均能提高预报纳什效率系数,其中反馈模拟最优,AR、KNN效果次之;反馈模拟对洪峰误差校正相比于KNN算法在短预见期内更为精确,两者均能减小AR法在洪峰误差校正上的不足;加入历史样本的KNN算法在洪峰误差校正上效果优于反馈模拟,可有效提高洪水预报精度。     

水库防洪预报预泄调度的风险分析

水库预报预泄调度是水库防洪调度的重要方式之一,它可以提高水库防洪能力．通过分析水库预报预泄调度可能产生的后果,给出了水库预报预泄调度风险率的定义．建立了考虑洪水预报误差情况下入库径流的随机模拟方法．通过大清河流域王快水库和龙门水库实际应用表明,在目前的洪水预报精度情况下,对于10年一遇以下的洪水,对这两座水库进行防洪预报预泄调度要冒汛限水位不能及时恢复的风险,进而可能影响水库的供水需求;而对于20年一遇洪水以上的洪水,对其进行预报预泄调度是非常必要的,所发挥的防洪效益也比较明显．     

基于蓄满超渗时空动态组合的网格新安江模型

为使网格新安江(Grid-XAJ)模型更好地应用于半干旱半湿润地区洪水模拟及预报,通过降雨和土壤含水量动态产流因子之间的判定关系,动态识别产流过程中网格的主导产流模式,构建基于蓄满超渗时空动态组合的网格新安江模型(Grid-XAJ-SIDE),并以半干旱的绥德流域为研究区域,将Grid-XAJ-SIDE模型与Grid-XAJ模型和网格格林安普特模型(Grid-GA)进行对比验证。结果表明:3个模型径流深模拟结果都较好,合格率均在80.0%以上;Grid-XAJ-SIDE模型的洪峰合格率(66.7%)比Grid-XAJ模型(53.0%)和Grid-GA模型(40.0%)有明显提升;Grid-XAJ-SIDE模型能更好地考虑降雨、土壤含水量对产流时空分布的影响。     

柘林水库坝址洪水与入库洪水系列分析

柘林水库的设计洪水以建库前历史坝址洪水为依据而设计,为了编制水库调度方案,需统一分析坝址洪水和入库洪水系列.为此,首先整理坝址洪水和入库洪水的基本资料,然后推算建库前及建库后的坝址洪水系列,最后建立洪峰与洪量系列之间的相关关系.计算和分析结果表明:柘林水库入库洪水洪峰流量增大系数为1.113,1 d洪量增大系数为1.0...     

淮河上中游复杂流域洪水预报

为了提高淮河洪水预报的精确度,以鲁台子和鲁蚌区间作为研究区域,选取2000—2017年之间的13场洪水资料,在降雨径流方面采用新安江三水源模型进行模拟预报,分别将鲁台子以上和鲁蚌区间分为9个和4个自然子流域,进行参数率定;对具有行蓄洪区的淮河干流河段进行节点概化,结合分流比法和马斯京根法,建立了具有行蓄洪区流域的洪水预报模拟方法,取得较好的模拟预报效果。研究结果表明:在洪量相对误差方面,鲁台子和鲁蚌区间的预报合格率都达到100%;在洪峰相对误差方面,鲁台子流域的合格率达到100%,而鲁蚌区间则达到92. 3%。2003年和2007年这2场大洪水的洪峰相对误差和确定性系数方面都得到显著改善。     

基于人工神经网络的龙羊峡水库入库径流预报

阐述神经网络是一个大规模的非线性功能系统,具有很强的非线性处理能力。人工神经网络模型是高度的非线性模型,能够有效地模拟本质为非线性的实际水文系统。又介绍了人工神经网络的结构、原理,并结合龙羊峡水库入库径流资料,利用BP神经网络方法进行预报分析,预测值和实测值的相对误差均在10%以内,预测结果相对较好。     

流溪河模型在白盆珠水库入库洪水模拟中的应用与研究

 利用流溪河模型对广东省内白盆珠水库的入库洪水进行模拟计算与分析研究。采用200 m精度的DEM数据、1 km的土地利用类型和土壤类型数据构建了模型,并将流域水系分为5级不同的河道,通过在河道上设置结点将河道分为48条虚拟河段,对不同的虚拟河段赋予不同的河道参数。在给定模型参数初值的基础上,分别用3场和11场洪水对模型参数进行了调整和验证。结果表明,流溪河模型对白盆珠水库入库洪水的模拟效果较好,推求的参数具有物理基础,对于洪水模拟具有广泛的适用性,在洪水模拟及预报方面有巨大的潜力。     

砂岩储层可压裂性评价方法研究

通过研究砂岩储层压裂裂缝起裂、扩展规律以及期望的裂缝形态,提出了砂岩储层可压裂性具体含义。分析KGD模型中各因素对压裂裂缝的影响规律,借助成熟的有限元方法对上述规律进行验证及补充,建立了砂岩储层可压裂性与储层岩石弹性模量和最小水平地应力之间的关系,绘制了可压裂性指标的变化规律,即弹性模量越高,最小水平地应力越小,砂岩储层的可压裂性越高。根据地震资料可以绘制砂岩储层的三维可压裂性分布图,可以为压裂选井选层提供参考。     

裂缝性砂岩油藏的水驱动态规律

从裂缝性砂岩油藏与常规油藏相渗曲线的差异入手,推导出了裂缝性油藏的水驱特征曲线的解析表达式,并绘制了理论曲线形状,从而发现了裂缝性砂岩油藏特有的水驱动态规律.与常规砂岩油藏具有明显不同,裂缝性砂岩油藏的水驱曲线在高含水期不再保持为一条直线而是出现“尾端上翘”现象.这一结论在现场实际和油藏数值模拟中得到了验证.对这类水驱曲线在裂缝性油藏动态预测中的有关问题进行了讨论.     

火成岩储层研究

从商 741地区测井资料及试油试采资料入手 ,结合钻井取心、测井资料及地震资料等相关资料 ,根据有关公式计算出了裂缝的产状和张开度及储层特征 ,对储层裂缝系统中裂缝的产状、张开度和储层的孔隙度、渗透率、饱和度进行了室内研究 ,并对火成岩成因油藏进行了分析 ,找出了一种适合该区火成岩储层的评价方法 .通过储层评价 ,确定了 4类储集层并划分出了储层的有效裂缝带 ,从而确定了该区原油分布的主要规律 ,以期指导该区的开发方案设计 .     

Potential methane reservoirs beneath Antarctica

Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14?kilometres thick and an estimated 21,000 petagrams (1?Pg equals 10(15)?g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300?metres in West Antarctica and 700?metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage.     

Fruit bats as reservoirs of Ebola virus

The first recorded human outbreak of Ebola virus was in 1976, but the wild reservoir of this virus is still unknown. Here we test for Ebola in more than a thousand small vertebrates that were collected during Ebola outbreaks in humans and great apes between 2001 and 2003 in Gabon and the Republic of the Congo. We find evidence of asymptomatic infection by Ebola virus in three species of fruit bat, indicating that these animals may be acting as a reservoir for this deadly virus.     

潘庄井田煤储层渗透率预测

为提高煤层开采水平,通过分析地应力、埋深、煤储层压力等对渗透率的影响,分别构建煤储层渗透率与其影响因素之间的拟合关系,利用定量关系对潘庄井田煤储层的渗透率进行了系统预测.预测结果显示:潘庄井田上主煤层3煤的渗透率大约在0.3×10-3～2.1×10-3μm2,下主煤层15煤的渗透率大约在0.4×10-3～0.8×10-3μm2.     

Exploration on ecological regulation of the reservoirs

Reservoir regulation process in the Yangtze River basin is mainly divided into two types of flood regulation and initiating benefit regulation. The present reservoir management system and operation mode are mainly for dealing with or coordinating of flood control and benefit initiation as well as benefit distribution among various beneficial functions. From the view point of river ecosystem protection, the current regulation mode has two kinds of problems ： firstly, most of the reservoir regulation plans do not consider ecosystem protection at downstream of dams and needs of environment protection in reservoir areas; secondly, integrated regulation or management of water resources is ignored. It is very necessary to improve reservoir regulation mode, bearing problems faced by regulation of the Three Gorges reservoir and issues related to cascade development and regulation in Tuojiang and Minjiang River basins in mind. In accordance with the concept of scientific development, and the philosophy of ＂ensuring a healthy Yangtze River and promoting the harmony between human and water＂, taking flood control, benefit initiation and eco-system as a whole, this paper put forward the basic consideration to improve reservoir regulation as follows ： on the basis of requirements of ecosystem protection at downstream of dams and needs of environment protection in reservoir areas, we should bring the functions of reservoir such as flood control and benefit initiation into full play, control the negative influence to the ecosystem at downstream of dams and the environment in reservoir areas in an endurable scope, and restore the ecosystem and the environment step by step. This paper put forward the relevant regulation process aiming at the idiographic problems such as protection of ecosystem at downstream of dams and environment in reservoir areas, protection of aquatic wildlife species and fish species, regulation of sediment and protection of wetland.