Automatic threshold and run parameter selection: a climatology for extreme hourly precipitation in Switzerland
Automatic threshold and run parameter selection: a climatology for extreme hourly precipitation in Switzerland
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DOI：
10.1007/s00704-014-1180-5
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发表时间：
2015-05-01
影响因子：
3.4
通讯作者：
Sueveges, M.
中科院分区：
文献类型：
--
作者：
Fukutome, S.;Liniger, M. A.;Sueveges, M.
在环境科学和设计中，对大量相对较短时间序列的极值分析的需求越来越大。在这里，我们提出了一个自动化的过程中的峰值超过阈值（POT）的方法极值理论，并使用它来提供极端的每小时降水在瑞士的气候学，POT的方法适合广义帕累托分布（GPD）的独立不稳定性高于一些高阈值。为了保证独立性，时间序列被修剪：间隔小于称为运行参数的固定间隔的时间间隔被认为是一个集群，除了集群最大值之外的所有数据都被丢弃。我们提出了一个现有的图形方法联合选择阈值和运行参数的自动化。对1981-2010年期间瑞士气象观测网59个站点的每小时降水量进行了分析。四季是分开考虑的。必要时，应用简单的去趋势。结果表明，不合理的大运行参数对GPD参数的估计有不利影响。所提出的方法产生的平均聚类大小，反映了季节和地理变化的每小时降水量的滞后依赖。气候学，如返回水平图和阿尔卑斯山横截面所示，反映了瑞士气候的已知方面。与日降水量不同。夏季雷暴路径在事件的季节频率上是可见的，而不是在罕见事件的振幅上。
Extreme value analyses of a large number of relatively short time series are in increasing demand in environmental sciences and design. Here, we present an automated procedure for the peaks-over-threshold (POT) approach to extreme value theory and use it to provide a climatology of extreme hourly precipitation in Switzerland, The POT approach fits the generalized Pareto distribution (GPD) to independent exceedances above some high threshold. To guarantee independence, the time series is pruned: exceedances separated by less than a fixed interval called the run parameter are considered a cluster, and all but the cluster maxima are discarded. We propose the automation of an existing graphical method for joint selection of threshold and run parameter. Hourly precipitation is analyzed at 59 stations of the MeteoSwiss observational network over the period 1981-2010. The four seasons are considered separately. When necessary, a simple detrending is applied. Results suggest that unnecessaiily large run parameters have adverse effects on the estimation of the GPD parameters. The proposed method yields mean cluster sizes that reflect the seasonal and geographical variation of lag dependence of hourly precipitation. The climatology, as represented by the return level maps and Alpine cross-section, mirror known aspects of the Swiss climate. Unlike for daily precipitation. summer thunderstorm tracks are visible in the seasonal frequency of events, rather than in the amplitude of rare events.