Applicability of Wakeby distribution in flood frequency analysis: a case study for eastern Australia   总被引：1，自引：0，他引：1       下载免费PDF全文

Ataur Rahman  Mohammad A. Zaman  Khaled Haddad  Salaheddine El Adlouni  Chi Zhang 《水文研究》2015,29(4):602-614

Parametric method of flood frequency analysis (FFA) involves fitting of a probability distribution to the observed flood data at the site of interest. When record length at a given site is relatively longer and flood data exhibits skewness, a distribution having more than three parameters is often used in FFA such as log‐Pearson type 3 distribution. This paper examines the suitability of a five‐parameter Wakeby distribution for the annual maximum flood data in eastern Australia. We adopt a Monte Carlo simulation technique to select an appropriate plotting position formula and to derive a probability plot correlation coefficient (PPCC) test statistic for Wakeby distribution. The Weibull plotting position formula has been found to be the most appropriate for the Wakeby distribution. Regression equations for the PPCC tests statistics associated with the Wakeby distribution for different levels of significance have been derived. Furthermore, a power study to estimate the rejection rate associated with the derived PPCC test statistics has been undertaken. Finally, an application using annual maximum flood series data from 91 catchments in eastern Australia has been presented. Results show that the developed regression equations can be used with a high degree of confidence to test whether the Wakeby distribution fits the annual maximum flood series data at a given station. The methodology developed in this paper can be adapted to other probability distributions and to other study areas. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

基于GIS组件的航迹标绘系统设计与实现     

崔文  崔焕东  张嵩 《测绘与空间地理信息》2012,(2):107-109

试验用飞行航迹设计完成后通常需要将各航路点和航段标绘在信息丰富的地图中,用于对航迹是否采用或修改与否进行决策并备案留存。手工标绘一条飞行航迹,耗时一般为15～20 min;基于GIS组件的航迹标绘系统,在VC环境下采用DTIS_MAPX组件,数据接口基于XML技术实现,首次将部队手工标绘改进为程序自动读取数据,标绘飞行航迹,并生成配套图例,成功实现了4 s标绘一条航迹,操作简便高效,提升了部队信息化作战保障能力。  相似文献   

Broken-line and complex frequency distributions     

C. R. Burch  P. N. Murgatroyd 《Mathematical Geology》1971,3(2):135-155

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应用GrADS绘图系统绘制小网格分析气候图     

况雪源  涂方旭 《气象研究与应用》2002,23(3):30-32

以广西 88站稳定通过 10℃起止日积温为例 ,采用回归分析方法 ,建立地理因素影响气候要素的气候方程 ,并结合 Gr ADS提供的数据处理及图形绘制功能 ,对余差项进行格点插值 ,最终求得小网格分析气候资料 ,并绘制气候分布图  相似文献   

基于COM结构的军事标图组件的设计与实现     

王净  刘建忠 《测绘学院学报》2004,21(4):308-310

针对当前军事标图软件在灵活性和可移植性等方面的缺陷，文中以组件式软件设计思想为指导，设计并实现了军事标图组件ComPlot，并通过应用实例验证了该组件的各项功能。  相似文献   

频率分析中特大洪水处理的新思考   总被引：6，自引：0，他引：6  

金光炎 《水文》2006,26(3):27-32,56

按以不确定性较小的实测洪水系列为主的原则,对含特大洪水系列的频率计算方法,包括经验频率、参数估计和适线问题进行了讨论,并结合实例作了剖析,提出了改进意见。  相似文献   

Statistical considerations for grain-size analyses of tills     

Alan M. Jacobs 《Mathematical Geology》1971,3(3):227-238

Relative percentages of sand, silt, and clay from samples of the same till unit are not identical because of different lithologies in the source areas, sorting in transport, random variation, and experimental error. Random variation and experimental error can be isolated from the other two as follows. For each particle-size class of each till unit, a standard population is determined by using a normally distributed, representative group of data. New measurements are compared with the standard population and, if they compare satisfactorily, the experimental error is not significant and random variation is within the expected range for the population. The outcome of the comparison depends on numerical criteria derived from a graphical method rather than on a more commonly used one-way analysis of variance with two treatments. If the number of samples and the standard deviation of the standard population are substituted in at-test equation, a family of hyperbolas is generated, each of which corresponds to a specific number of subsamples taken from each new sample. The axes of the graphs of the hyperbolas are the standard deviation of new measurements (horizontal axis) and the difference between the means of the new measurements and the standard population (vertical axis). The area between the two branches of each hyperbola corresponds to a satisfactory comparison between the new measurements and the standard population. Measurements from a new sample can be tested by plotting their standard deviation vs. difference in means on axes containing a hyperbola corresponding to the specific number of subsamples used. If the point lies between the branches of the hyperbola, the measurements are considered reliable. But if the point lies outside this region, the measurements are repeated. Because the critical segment of the hyperbola is approximately a straight line parallel to the horizontal axis, the test is simplified to a comparison between the means of the standard population and the means of the subsample. The minimum number of subsamples required to prove significant variation between samples caused by different lithologies in the source areas and sorting in transport can be determined directly from the graphical method. The minimum number of subsamples required is the maximum number to be run for economy of effort.  相似文献   

顾及方向遮蔽性的反距离权重插值法   总被引：1，自引：0，他引：1  

李正泉  吴尧祥 《测绘学报》2015,44(1):91-98

针对反距离权重(IDW)空间插值在实际应用中存在的缺陷,本文对IDW插值算法进行了优化改进,提出了调和反距离权重(AIDW)空间插值方式。该插值方式在传统IDW的算式中增加了反映样点方位的调和权重系数K,其插值过程综合考虑了样点距离和样点方位对插值点的共同影响。理论分析和实例应用表明:AIDW插值方式可减小或克服样点分布不均的IDW插值缺陷,使离散点的空间插值结果更趋于合理,其等值线绘制亦可有效避免传统IDW插值中的孤立圆及同心圆现象,使等值线的绘制更接近于人工作业。  相似文献   

运用三维声纳图像的水底全景拼接与绘制     

李志华  李秋峦 《测绘科学》2015,40(6):146-150

针对海量声纳图像多帧配准引起的误差累积问题,该文提出了一种基于三维声纳图像的水底全景拼接与绘制方法。首先通过相邻两帧图像最近邻点迭代,并结合GPS、姿态仪信息和X84控制点剔除方法,减少非重叠区域控制点对的存在以提高配准精度,实现相邻帧图像精确配准。然后采用四元组参数对所有精确配准矩阵进行拟牛顿最优化处理,获取所有声纳帧之间最佳配准关系,减少多帧配准引起的累积误差,实现三维图像高精度全局配准。湖试与海试实验结果表明,该方法有效地减少了海量声纳图像多帧配准引起的累积误差,实现了三维声纳图像水底全景高精度拼接与绘制,达到了预期目标。  相似文献   

三维气象GIS平台关键技术研究与实现     

张学全  王伟  王鹏  邢平 《气象科技》2015,43(2):226-231

针对三维GIS的发展应用以及气象服务对于高效决策和直观可视性的要求,开发了具有自主知识产权的三维气象GIS平台。本文从体系结构、功能、数据访问及组件方面介绍了系统的设计方法,并详细论述了平台的关键实现技术,包括气象数据组织、气象标绘、二维图层和三维体绘制技术。该系统能够高效加载海量的二三维气象数据,并支持气象标绘和分析等功能。该系统运行稳定,可视化效果突出,为气象数据处理、数值预报、气象模拟仿真等气象服务搭建了一个坚实的三维基础平台,具有重要的应用价值。  相似文献