Heterogeneity measures in hydrological frequency analysis: review and new developments
| Autor: | Ana Isabel Requena, Taha B. M. J. Ouarda, Fateh Chebana |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
lcsh:GE1-350
Frequency analysis 010504 meteorology & atmospheric sciences Computer science lcsh:T Homogeneity (statistics) 0208 environmental biotechnology Monte Carlo method lcsh:Geography. Anthropology. Recreation 02 engineering and technology 01 natural sciences lcsh:Technology Confidence interval lcsh:TD1-1066 020801 environmental engineering law.invention lcsh:G Homogeneous law Econometrics Probability distribution lcsh:Environmental technology. Sanitary engineering lcsh:Environmental sciences 0105 earth and related environmental sciences Quantile |
| Zdroj: | Hydrology and Earth System Sciences, Vol 21, Iss 3, Pp 1651-1668 (2017) |
| ISSN: | 1607-7938 1027-5606 |
| Popis: | Some regional procedures to estimate hydrological quantiles at ungauged sites, such as the index-flood method, require the delineation of homogeneous regions as a basic step for their application. The homogeneity of these delineated regions is usually tested providing a yes/no decision. However, complementary measures that are able to quantify the degree of heterogeneity of a region are needed to compare regions, evaluate the impact of particular sites, and rank the performance of different delineating methods. Well-known existing heterogeneity measures are not well-defined for ranking regions, as they entail drawbacks such as assuming a given probability distribution, providing negative values and being affected by the region size. Therefore, a framework for defining and assessing desirable properties of a heterogeneity measure in the regional hydrological context is needed. In the present study, such a framework is proposed through a four-step procedure based on Monte Carlo simulations. Several heterogeneity measures, some of which commonly known and others which are derived from recent approaches or adapted from other fields, are presented and developed to be assessed. The assumption-free Gini index applied on the at-site L-variation coefficient (L-CV) over a region led to the best results. The measure of the percentage of sites for which the regional L-CV is outside the confidence interval of the at-site L-CV is also found to be relevant, as it leads to more stable results regardless of the regional L-CV value. An illustrative application is also presented for didactical purposes, through which the subjectivity of commonly used criteria to assess the performance of different delineation methods is underlined. |
| Databáze: | OpenAIRE |
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