Comparison of Two Nonstationary Flood Frequency Analysis Methods within the Context of the Variable Regime in the Representative Polish Rivers

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• 作者：Witold G. Strupczewski ; Krzysztof Kochanek ; Ewa Bogdanowicz…
• 关键词：Keywordnon ; stationary flood frequency analysis ; maximum likelihood ; covariance ; two ; stage methodology ; L ; moments
• 刊名：Acta Geophysica
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：64
• 期：1
• 页码：206-236
• 全文大小：539KB
• 刊物主题：Geophysics/Geodesy; Structural Geology; Geotechnical Engineering & Applied Earth Sciences;
• 出版者：Springer International Publishing
• ISSN：1895-7455
• 卷排序：64

文摘

Changes in river flow regime resulted in a surge in the number of methods of non-stationary flood frequency analysis. Common assumption is the time-invariant distribution function with time-dependent location and scale parameters while the shape parameters are time-invariant. Here, instead of location and scale parameters of the distribution, the mean and standard deviation are used. We analyse the accuracy of the two methods in respect to estimation of time-dependent first two moments, time-invariant skewness and time-dependent upper quantiles. The method of maximum likelihood (ML) with time covariate is confronted with the Two Stage (TS) one (combining Weighted Least Squares and L-moments techniques). Comparison is made by Monte Carlo simulations. Assuming parent distribution which ensures the asymptotic superiority of ML method, the Generalized Extreme Value distribution with various values of linearly changing in time first two moments, constant skewness, and various time-series lengths are considered. Analysis of results indicates the superiority of TS methods in all analyzed aspects. Moreover, the estimates from TS method are more resistant to probability distribution choice, as demonstrated by Polish rivers’ case studies.