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Flood statistics with seasonal differentiated mixed distributions

季节差异混合分布的洪水统计

基本信息

批准号：
260442043
负责人：
Professor Dr. Andreas H. Schumann
金额：
--
依托单位：
Lehrstuhl für Ingenieurhydrologie und Wasserwirtschaft
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/260442043?language=en
关键词：
Flood statistics seasonal differentiated mixed

项目摘要

In the last decades the estimation of flood probabilities by extreme value statistics for annual maximum flows was largely standardized in Germany by rules such as the DWA M -552. However the basic conditions for the application of extreme value statistics to the annual maximum values which were already emphasized by Gumbel in 1941 (the sample is homogeneous, i.e. each value of the sample is subject to the same distribution, and the causes of the events are the same) are not satisfied. The causes of the observed flood events are complex and varied. E.g. floods, caused by rain and snowmelt are mixed within series of annual maximum flows. It can be shown that winter and summer floods have different frequencies, which can be described by different distribution functions. The seasonal differences in the flood genesis, which is reflected in the seasonal variability of the occurrence of flood events of different sizes, are an important feature of the flood regime of a catchment. An inclusion of this feature in flood statistical analyzes can reduce their uncertainty and improves the estimation of probabilities for extremely rare flood events. As part of the planned work the seasonality of floods in different German regions will be analyzed. The results will be taken into account in the probabilistic assessment of extremely large events by mixed distributions. It is assumed that distribution functions of flood events, which differ in their origins can be determined with the help of seasonal differentiated analyzes. The different seasons will be separated by hydrological indicators which are derived from analyses of observed flood events. The seasonal flood probabilities can be described by different statistical approaches and finally combined to distributions of annual maximum values . Several mathematical options for calculating seasonal differentiated flood statistics will be compared. By considering a larger number of catchments in Bavaria, Thuringia and Saxony the generality of the newly developed approaches for generation of mixed distributions will be demonstrated. A significant improvement of flood statistical analyzes is expected as a result of the planned research work. The results of this basic research will be widely applicable for practice.

在过去的几十年中，在德国，通过DWA M-552等规则，通过年最大流量的极值统计来估计洪水概率在很大程度上是标准化的。然而，Gumbel在1941年已经强调的将极值统计应用于年最大值的基本条件（样本是均匀的，即样本的每个值都服从相同的分布，并且事件的原因是相同的）并不满足。所观察到的洪水事件的原因是复杂和多样的。例如，由降雨和融雪引起的洪水混合在一系列年最大流量中。结果表明，冬、夏季洪水发生频率不同，可用不同的分布函数描述。洪水成因的季节性差异是流域洪水状况的一个重要特征，它反映在不同规模洪水事件发生的季节性变化上。在洪水统计分析中包含这一特征可以减少其不确定性，并提高对极其罕见的洪水事件的概率估计。作为计划工作的一部分，将分析德国不同地区洪水的季节性。在通过混合分布对特大事件进行概率评估时，将考虑这些结果。它是假定的洪水事件的分布函数，这在他们的起源不同，可以确定与季节分化分析的帮助下。不同的季节将根据从观测到的洪水事件分析中得出的水文指标加以区分。季节性洪水概率可以用不同的统计方法来描述，最后组合成年最大值的分布。将比较用于计算季节性差异洪水统计数据的几种数学选择。通过考虑大量的集水区在巴伐利亚州，图林根州和萨克森的新开发的方法产生的混合分布的一般性将被证明。预计计划中的研究工作将大大改进洪水统计分析。这一基础研究的成果将广泛应用于实践。