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Item type:Publication, Access status: without files , Residual Dynamics in Hydrological Models: Insights from a large sample of catchments and models(Elsevier, 2025-11); ; ; ; Vogel, Richard M.The study investigates the properties of residuals from 78 hydrological models applied to 419 distinct catchments over the contiguous United States in a large multi-catchment, multi-model approach. Such dataset provides a foundation for a robust analysis, allowing for an in-depth investigation of residual characteristics. The research focuses on key properties such as sample shape properties (L-skewness and L-kurtosis) investigated with conventional L-moment diagrams (λ4/λ2 vs λ3/λ2) and L-moment diagrams adapt for symmetric distributions (λ6/λ2 vs λ4/λ2). Other investigated characteristics are residuals heteroscedasticity, and residual correlation. Additional focus of the study is how these characteristics vary across the different models, hydrological regimes, and under the application of different residual transformations. Specifically, the impact of two transformations (Box-Cox and logarithmic) is evaluated on stabilizing such properties. Additionally, the removal of seasonality is analyzed as a separate process, revealing significant effects in stabilizing higher-order moments, greatly reducing heavy-tails in residuals, even in the absence of any transformation. While the removal of seasonality has notable effects on the statistical properties of the residuals, its effect alone is limited in reducing heteroskedasticity, where transformations play instead a key role, effectively approximating a homoscedastic distribution. Upper and lower tails correlations are also investigated, showing distinct patterns different from general correlation behaviors. The findings of this study lays the groundwork for a conscious and informed construction of stochastic error models for uncertainty estimation in hydrological modelling, as well as for the development of new metrics for model calibration.Publicationtype: Journal Article20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Statistical hydrology(2011-01-01); ; ; ; Hydrological phenomena such as precipitation, floods, and droughts are inherently random by nature. Due to the complexity of the hydrologic system, these physical processes are not fully understood and reliable deterministic mathematical models are still to be developed. Therefore, in order to provide useful analyses for designing hydraulic facilities and infrastructures, statistical approaches have been commonly adopted. This chapter describes some statistical topics widely used in hydrology. Among the large number of subjects available in literature, the attention is focalized on some of them particularly useful either for innovative hydrological analyses or for an appropriate application of common procedures.Precisely, the chapter describes in details the stationary hypothesis on hydrological time series, the univariate extreme value analysis procedure, the intensity-duration-frequency curves, the copula function useful for multivariate analysis, and the regional flood frequency analysis.Publicationtype: Book Part11