Spatio-temporal consideration of the impact of flood event types on flood statistic
Spatio-temporal consideration of the impact of flood event types on flood statistic
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DOI：
10.1007/s00477-019-01690-2
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发表时间：
2019-05
影响因子：
4.2
通讯作者：
S. Fischer;A. Schumann
中科院分区：
文献类型：
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作者：
S. Fischer;A. Schumann
洪水事件可能有非常不同的生成过程。洪水可能源于高强度降雨、长时间降雨或积雪融化。其他因素，例如初始土壤湿度条件，也影响洪水的空间和时间特征。因此，洪水的类型学通常被用来根据洪水的产流过程对洪水进行分类。考虑到多年来洪水情况的变化，如气候或人为变化，问题是这些变化对某些洪水类型的发生有多大影响。这不仅涉及洪水事件类型的频率随时间的变化，而且还涉及导致不同区域模式的空间变化。我们调查了洪水事件类型发生频率的变化、它们的空间格局以及对极端事件估计的后果。许多流域特征与特定的洪水类型密切相关，例如融雪高程。短雨事件的空间范围有限，并在较小的集水区引起洪水，而在大流域，大洪峰需要长时间和空间上扩展的降雨事件。在这项研究中，洪水类型是基于对峰容关系的分析，允许考虑只有部分很少的气象数据的长时间观测，例如雪高度。对于由此产生的洪水类型，可以检测到时间变化和空间模式，并将其与生成过程和流域特征联系起来。最后，利用部分持续时间序列的季节混合模型研究了变化对洪水统计的影响，该模型能够分别对事件类型和季节进行建模，并将它们合并到年度模型中。
Flood events can have very different generating processes. Floods may originate from high intensity rainfall, long-duration rainfall or snowmelt. Other factors, e.g. initial soil moisture conditions, also affect the spatial and temporal characteristics of floods. Hence, a typology for floods is often used to classify floods according to their runoff generating processes. Having in mind the changing circumstances for floods over the years, like climatic or anthropogenic changes, the question arises in how far these changes affect the occurrence of certain flood types. This does not only concern a change of frequency of flood event types over time, but also spatial changes resulting in different regional patterns. We investigate the changes of the frequency of occurrence of flood event types, their spatial patterns and the consequences for estimating extreme events. Many watershed characteristics are strongly related with specific flood types, e.g. elevation with snowmelt. Short-rain events are limited in their spatial extension and cause floods in smaller catchments, whereas in large river basins a large flood peak requires a long and spatially extended rain event. In this study, the flood typology is based on analyses of the peak-volume relationship allowing to consider long periods of observation with partially only few meteorological data, e.g. snow height. For the resulting flood types, temporal changes and spatial patterns are detected and connected with the generating processes as well as catchment characteristics. Finally, the impact of changes on the flood statistic is investigated by using a seasonal mixture model of partial duration series that is able to model event types and seasons separately and combines them in an annual model.