Parametric uncertainty and sensitivity analysis of hydrodynamic processes for a large shallow freshwater lake.
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| Title: | Parametric uncertainty and sensitivity analysis of hydrodynamic processes for a large shallow freshwater lake. |
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| Alternate Title: | Incertitude et analyse de sensibilité des paramètres des processus hydrodynamiques d'un grand lac d'eau douce peu profond. |
| Authors: | Li, Yiping1,2 (AUTHOR) liyiping@hhu.edu.cn, Tang, Chunyan2 (AUTHOR), Zhu, Jianting3 (AUTHOR), Pan, Baozhu4 (AUTHOR), Anim, Desmond O.2 (AUTHOR), Ji, Yong5 (AUTHOR), Yu, Zhongbo6 (AUTHOR), Acharya, Kumud7 (AUTHOR) |
| Source: | Hydrological Sciences Journal/Journal des Sciences Hydrologiques. Jun2015, Vol. 60 Issue 6, p1078-1095. 18p. |
| Subjects: | Uncertainty, Computational hydrodynamics software, Probability theory, Fresh water, Lakes |
| Geographic Terms: | China |
| Abstract (English): | A parametric uncertainty and sensitivity analysis of hydrodynamic processes was conducted for a large shallow freshwater lake, Lake Taihu, China. Ten commonly used parameters in five groups were considered including: air–water interface factor, water–sediment interface factor, surrounding terrain factor, turbulent diffusion parameters and turbulent intensity parameters. Latin hypercube sampling (LHS) was used for sampling the parametric combinations, which gave predictive uncertainty results directly without using surrogate models, and the impacts of different parametric distribution functions on the results were investigated. The results showed that the different parametric distribution functions (e.g. uniform, normal, lognormal and triangular) for sampling had very little impact on the uncertainty and sensitivity analysis of the lake hydrodynamic model. The air–water interface factor (wind drag coefficient) and surrounding terrain factor (wind shelter coefficient) had the greatest influence on the spatial distribution of lake hydrodynamic processes, especially in semi-closed bays and lake regions with complex topography, accounting for about 60–70% and 20%, respectively, of the uncertainty on the results. Vertically, velocity in the surface layer was also largely influenced by the two factors, followed by velocity in the bottom layer; the middle velocity had minimal impact. Likewise, the water–sediment interface factor (i.e. bottom roughness height) ranked third, contributing about 10% to the uncertainty of the hydrodynamic processes of the lake. In contrast, turbulent diffusion parameters and turbulent intensity parameters in the lake hydrodynamic model had little effect on the uncertainty of simulated results (less than 1% contribution). The findings were sufficiently significant to reduce the parameter uncertainties and calibration workload of the hydrodynamic model in large shallow lakes.Editor Z. W. Kundzewicz; Associate editor S. Grimaldi [ABSTRACT FROM AUTHOR] |
| Abstract (French): | Nous avons réalisé une analyse d’incertitude et de sensibilité des paramètres des processus hydrodynamiques d’un grand lac d’eau douce peu profond, le lac Taihu, en Chine. Dix paramètres couramment utilisés répartis en cinq groupes ont été pris en compte, notamment : le facteur d’interface air-eau, le facteur d’interface eau–sédiments, le facteur de terrain environnant, les paramètres de diffusion turbulente et les paramètres d’intensité de la turbulence. L’échantillonnage par hypercube latin (EHL) a été utilisé pour échantillonner les combinaisons paramétriques, ce qui a donné directement les résultats de l’incertitude prédictive, sans avoir recours à des modèles de substitution. Les impacts de différentes fonctions de répartition des paramétres sur les résultats ont été étudiés. Les résultats montrent que les différentes fonctions de répartition des paramétres (par exemple uniforme, normale, log-normale et triangulaire) utilisées pour l’échantillonnage ont très peu d’impact sur l’analyse d’incertitude et de sensibilité du modèle hydrodynamique du lac. Le facteur d’interface air-eau (coefficient de traînée du vent) et le facteur de terrain environnant (coefficient d’abri au vent) jouent les rôles les plus importants dans la distribution spatiale des processus hydrodynamiques du lac, en particulier dans les baies semi-fermées et les régions du lac ayant une topographie complexe, avec des contributions respectives d’environ 60–70% et 20% sur l’incertitude sur les résultats. Verticalement, la vitesse dans la couche de surface a également été largement influencée par ces deux facteurs, suivie par la vitesse dans la couche inférieure, la vitesse dans la couche intermédiaire subissant un impact minime. De même, le facteur d’interface eau-sédiments (c’est-à-dire la hauteur de rugosité du fond) s’est classée troisième, avec environ 10% de contribution à l’incertitude des processus hydrodynamiques du lac. En revanche, les paramètres de diffusion turbulente et les paramètres d’intensité de la turbulence du modèle hydrodynamique du lac ont peu d’effet sur l’incertitude des résultats simulés (contribution inférieure à 1%). Ces résultats permettent de réduire les incertitudes des paramètres et la charge de travail nécessaire au calage des modèles hydrodynamiques des grands lacs peu profonds. [ABSTRACT FROM PUBLISHER] |
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| Database: | Engineering Source |
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| Abstract: | A parametric uncertainty and sensitivity analysis of hydrodynamic processes was conducted for a large shallow freshwater lake, Lake Taihu, China. Ten commonly used parameters in five groups were considered including: air–water interface factor, water–sediment interface factor, surrounding terrain factor, turbulent diffusion parameters and turbulent intensity parameters. Latin hypercube sampling (LHS) was used for sampling the parametric combinations, which gave predictive uncertainty results directly without using surrogate models, and the impacts of different parametric distribution functions on the results were investigated. The results showed that the different parametric distribution functions (e.g. uniform, normal, lognormal and triangular) for sampling had very little impact on the uncertainty and sensitivity analysis of the lake hydrodynamic model. The air–water interface factor (wind drag coefficient) and surrounding terrain factor (wind shelter coefficient) had the greatest influence on the spatial distribution of lake hydrodynamic processes, especially in semi-closed bays and lake regions with complex topography, accounting for about 60–70% and 20%, respectively, of the uncertainty on the results. Vertically, velocity in the surface layer was also largely influenced by the two factors, followed by velocity in the bottom layer; the middle velocity had minimal impact. Likewise, the water–sediment interface factor (i.e. bottom roughness height) ranked third, contributing about 10% to the uncertainty of the hydrodynamic processes of the lake. In contrast, turbulent diffusion parameters and turbulent intensity parameters in the lake hydrodynamic model had little effect on the uncertainty of simulated results (less than 1% contribution). The findings were sufficiently significant to reduce the parameter uncertainties and calibration workload of the hydrodynamic model in large shallow lakes.Editor Z. W. Kundzewicz; Associate editor S. Grimaldi [ABSTRACT FROM AUTHOR] |
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| ISSN: | 02626667 |
| DOI: | 10.1080/02626667.2014.948444 |
