Sensitivity analysis and auto-calibration of an integral dynamic model for river water quality

2002 ◽  
Vol 45 (9) ◽  
pp. 325-332 ◽  
Author(s):  
A. van Griensven ◽  
A. Francos ◽  
W. Bauwens
Keyword(s):  
Sensitivity Analysis ◽  
Assessment Tool ◽  
Calibration Procedure ◽  
Distributed Model ◽  
Shuffled Complex Evolution ◽  
Physically Based ◽  
High Pollution ◽  
Individual Variables ◽  
Weighting Problem ◽  
The One

ESWAT – Extended Soil and Water Assessment Tool – was developed to allow for an integral modelling of the water quantity and quality processes in river basins. ESWAT is a physically based, semi-distributed model, with a moderate-to-large number of parameters and input and output variables (depending on the desegregation scheme). An auto-calibration procedure was implemented for the optimisation of the process parameters. The procedure is based on a new approach for multi-objective calibration and incorporates the algorithms of the Shuffled Complex Evolution Method. The optimisation uses a global optimisation criterion, whereby several output variables can be taken into account simultaneously. A statistical method enables the aggregation of the objective functions for individual variables, hereby avoiding the weighting problem. To select the important parameters for the optimisation, a sensitivity analysis precedes the calibration. The latter analysis is based on the One-factor-At-a-Time (OAT) design approach. The sensitivity analysis and the calibration procedure are applied to the river Dender in Belgium. The river is characterised by high pollution loads and long residence times in summer periods.

scholarly journals Analysis of hydrological processes with semi-distributed model

2021 ◽  
Author(s):  
Rahmatullah Sediqi ◽  
Mustafa Tombul
Keyword(s):  
Sensitivity Analysis ◽  
Assessment Tool ◽  
Swat Model ◽  
Hydrological Processes ◽  
Distributed Model ◽  
Model Sensitivity ◽  
Discharge Data ◽  
Calibration And Validation ◽  
Physically Based ◽  
Calibration Program

The Soil and Water Assessment Tool (SWAT), a semi-distributed physically-based hydrological model, is broadly used for simulating streamflow and analyzing hydrological processes in the basin. The SWAT model was applied to analyze the hydrological processes in Göksu Himmetli, Zamanti-Ergenuşağı, Göksun Poskoflu ve Hurman-Gözler Üstü sub-basins in the upper region of Seyhan and Ceyhan watersheds located in the south of Turkey. Model sensitivity analysis, calibration, and validation were performed using SWAT-CUP automatic calibration program and SUFI-2 algorithm. According to the model sensitivity analysis results, the most sensitive parameters in these basins have been seen as CN2, ALPHA_BNK, CH_K2, and GW_DELAY. In this study, 11 years (1994-2004) meteorological and eight years (1997-2004) observed flow data were used, three years for the model warm-up period, five years (1997-2001) for calibration, and three years (2002-2004) for validation. The model statistical performance was evaluated using the Nash Sutcliffe Efficiency (NSE) as the objective function. As the result of the model calibration and validation, the NSE value in the considered four sub-basins varied between 0,70 - 0,90. The results obtained in the study showed a relatively high correlation between the observed and simulated discharge data.

scholarly journals Comparison of two different approaches for sensitivity analysis in Heihe River basin (China)

2019 ◽  
Vol 20 (1) ◽  
pp. 319-327 ◽  
Author(s):  
Aidi Huo ◽  
Zhikai Huang ◽  
Yuxiang Cheng ◽  
Michael W. Van Liew
Keyword(s):  
Sensitivity Analysis ◽  
River Basin ◽  
Assessment Tool ◽  
Calibration Procedure ◽  
Heihe River Basin ◽  
Heihe River ◽  
Efficiency Coefficient ◽  
Flexible Tool ◽  
Shuffled Complex Evolution ◽  
The Heihe River Basin

Abstract Distributed watershed models should pass through a careful sensitivity analysis and calibration procedure before they are utilized as a decision making aid in the planning and management of water resources. Although manual approaches are still frequently used for sensitivity and calibration, they are tedious, time consuming, and require experienced personnel. This paper describes two typical and effective automatic approaches for sensitivity analysis and calibration for the Soil and Water Assessment Tool (SWAT). These included the Sequential Uncertainty Fitting (SUFI-2) algorithm and Shuffled Complex Evolution (SCE-UA) algorithm. The results show the following. (1) The main factor that influences the simulated accuracy of the Heihe River basin runoff is the Soil Conservation Service (SCS) runoff curve parameters. (2) SWAT performed very well in the Heihe River basin. According to the observed runoff data from 2005 to 2013, the determination coefficient R2 of the simulation and the efficiency coefficient (Ens) of the model was higher than 0.8. (3) Compared with the Shuffled Complex Evolution, the SUFI-2 algorithm provides almost the same overall ranking of the sensitive parameters, but it is found to require less time with higher accuracy. The SUFI-2 provides a practical and flexible tool to attain reliable deterministic simulation and uncertainty analysis of SWAT, it can lead to a better understanding and to better estimated values and thus reduced uncertainty.

Sensitivity Analysis of a Physically Based Distributed Model

2016 ◽  
Vol 30 (5) ◽  
pp. 1669-1684 ◽  
Author(s):  
Vesna Đukić ◽  
Zoran Radić
Keyword(s):  
Sensitivity Analysis ◽  
Distributed Model ◽  
Physically Based

scholarly journals Effect of DEM resolution on SWAT outputs of runoff, sediment and nutrients

2010 ◽  
Vol 7 (4) ◽  
pp. 4411-4435 ◽  
Author(s):  
S. Lin ◽  
C. Jing ◽  
V. Chaplot ◽  
X. Yu ◽  
Z. Zhang ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Line Graph ◽  
Distributed Model ◽  
Dem Resolution ◽  
Environmental Models ◽  
Digital Elevation ◽  
Study Results ◽  
Runoff Sediment ◽  
The One ◽  
The Impact

Abstract. Digital Elevation Models (DEMs) have been successfully used in a large range of environmental issues. Several methods such as digital contour interpolation and remote sensing have allowed the generation of DEMs, some of which are now freely available for almost the entire globe. The Soil and Water Assessment Tool (SWAT) is a widely used semi-distributed model operating at the watershed level and has previously been shown to be very sensitive to the quality of the input topographic information. The objective of this study was to evaluate the impact of DEMs generated from different data sources, respectively DLG5m (local Digital Line Graph, 5 m interval), ASTER30m (1 arc-s ASTER Global DEM Version 1, approximately 30 m resolution), and SRTM90m (3 arc-s SRTM Version 4, approximately 90 m resolution), on SWAT predictions for runoff, sediment, total phosphor (TP) and total nitrogen (TN). Eleven resolutions, from 5 m to 140 m, were considered in this study. Results indicate that the predictions of TPs and TNs decreased substantially with coarser resampled resolution. Slightly decreased trends could be found in the predicted sediments when DEMs were resampled to coarser resolutions. Predicted runoffs were not sensitive to resampled resolutions. The predicted outputs based on DLG5m were more sensitive to resampled resolutions than those based on ASTER30m and SRTM90m. At original resolutions, the predicted outputs based on ASTER30m and SRTM90m were similar, but the predicted TNs and TPs based on ASTER30m and SRTM90m were much lower than the one based on DLG5m. For the predicted TNs and TPs, which were substantially sensitive to DEM resolutions, the output accuracies of SWAT derived from ASTER30m and SRTM90m could be improved by down-scaled resampling, but they could not improve on finer DEM (DLG5m) at the same resolution. This study helps GIS environmental model users to understand the sensitivities of SWAT to DEM resolution, and choose feasible DEM data for environmental models.

scholarly journals Validation of a one-dimensional model of the systemic arterial tree

2009 ◽  
Vol 297 (1) ◽  
pp. H208-H222 ◽  
Author(s):  
Philippe Reymond ◽  
Fabrice Merenda ◽  
Fabienne Perren ◽  
Daniel Rüfenacht ◽  
Nikos Stergiopulos
Keyword(s):  
Constitutive Law ◽  
Distributed Model ◽  
Arterial Tree ◽  
One Dimensional ◽  
Continuity Equations ◽  
Nonlinear Viscoelastic ◽  
Model Predictions ◽  
The One ◽  
D Model ◽  
Systemic Arterial Tree

A distributed model of the human arterial tree including all main systemic arteries coupled to a heart model is developed. The one-dimensional (1-D) form of the momentum and continuity equations is solved numerically to obtain pressures and flows throughout the systemic arterial tree. Intimal shear is modeled using the Witzig-Womersley theory. A nonlinear viscoelastic constitutive law for the arterial wall is considered. The left ventricle is modeled using the varying elastance model. Distal vessels are terminated with three-element windkessels. Coronaries are modeled assuming a systolic flow impediment proportional to ventricular varying elastance. Arterial dimensions were taken from previous 1-D models and were extended to include a detailed description of cerebral vasculature. Elastic properties were taken from the literature. To validate model predictions, noninvasive measurements of pressure and flow were performed in young volunteers. Flow in large arteries was measured with MRI, cerebral flow with ultrasound Doppler, and pressure with tonometry. The resulting 1-D model is the most complete, because it encompasses all major segments of the arterial tree, accounts for ventricular-vascular interaction, and includes an improved description of shear stress and wall viscoelasticity. Model predictions at different arterial locations compared well with measured flow and pressure waves at the same anatomical points, reflecting the agreement in the general characteristics of the “generic 1-D model” and the “average subject” of our volunteer population. The study constitutes a first validation of the complete 1-D model using human pressure and flow data and supports the applicability of the 1-D model in the human circulation.

Multi-Criteria and Time Dependent Sensitivity Analysis of an Event-Oriented and Physically-Based Distributed Sediment and Runoff Model

2021 ◽  
pp. 126268
Author(s):  
Menberu B. Meles ◽  
Dave C. Goodrich ◽  
Hoshin V. Gupta ◽  
I. Shea Burns ◽  
Carl L. Unkrich ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Time Dependent ◽  
Physically Based ◽  
Runoff Model

scholarly journals Global Sensitivity Analysis of a Homogenized Constrained Mixture Model of Arterial Growth and Remodeling

2021 ◽  
Author(s):  
Sebastian Brandstaeter ◽  
Sebastian L. Fuchs ◽  
Jonas Biehler ◽  
Roland C. Aydin ◽  
Wolfgang A. Wall ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Global Sensitivity Analysis ◽  
Model Parameters ◽  
Computational Studies ◽  
Growth And Remodeling ◽  
Global Sensitivity ◽  
Output Variability ◽  
Constrained Mixture ◽  
The One ◽  
Influential Parameters

AbstractGrowth and remodeling in arterial tissue have attracted considerable attention over the last decade. Mathematical models have been proposed, and computational studies with these have helped to understand the role of the different model parameters. So far it remains, however, poorly understood how much of the model output variability can be attributed to the individual input parameters and their interactions. To clarify this, we propose herein a global sensitivity analysis, based on Sobol indices, for a homogenized constrained mixture model of aortic growth and remodeling. In two representative examples, we found that 54–80% of the long term output variability resulted from only three model parameters. In our study, the two most influential parameters were the one characterizing the ability of the tissue to increase collagen production under increased stress and the one characterizing the collagen half-life time. The third most influential parameter was the one characterizing the strain-stiffening of collagen under large deformation. Our results suggest that in future computational studies it may - at least in scenarios similar to the ones studied herein - suffice to use population average values for the other parameters. Moreover, our results suggest that developing methods to measure the said three most influential parameters may be an important step towards reliable patient-specific predictions of the enlargement of abdominal aortic aneurysms in clinical practice.

scholarly journals A Business Model Framework to Characterize Digital Multisided Platforms

2020 ◽  
Vol 6 (1) ◽  
pp. 10 ◽  
Author(s):  
Marco Ardolino ◽  
Nicola Saccani ◽  
Federico Adrodegari ◽  
Marco Perona
Keyword(s):  
Information And Communication Technologies ◽  
Assessment Tool ◽  
Empirical Studies ◽  
Communication Technologies ◽  
Model Framework ◽  
Recent Developments ◽  
Information And Communication ◽  
Multiple Case ◽  
The One

Businesses grounded upon multisided platforms (MSPs) are found in a growing number of industries, thanks to the recent developments in Internet and digital technologies. Digital MSPs enable multiple interactions among users of different sides through information and communication technologies. The understanding of the characteristics and constituents of MSPs is fragmented along different literature streams. Moreover, very few empirical studies have been carried out to date. In order to fill this gap, this paper presents a three-level framework that describes a digital MSP. The proposed framework is based on literature analysis and multiple case study. On the one hand, the framework can be used to describe MSP as it provides an operationalization of the concept through the identification of specific dimensions, variables and items; on the other hand, it can be used as an assessment tool by practitioners, as exemplified by the three empirical applications presented in this paper.

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