Parameter estimation in semi‐distributed hydrological catchment modelling using a multi‐criteria objective function     

Hamed Rouhani  Patrick Willems  Guido Wyseure  Jan Feyen 《水文研究》2007,21(22):2998-3008

Output generated by hydrologic simulation models is traditionally calibrated and validated using split‐samples of observed time series of total water flow, measured at the drainage outlet of the river basin. Although this approach might yield an optimal set of model parameters, capable of reproducing the total flow, it has been observed that the flow components making up the total flow are often poorly reproduced. Previous research suggests that notwithstanding the underlying physical processes are often poorly mimicked through calibration of a set of parameters hydrologic models most of the time acceptably estimates the total flow. The objective of this study was to calibrate and validate a computer‐based hydrologic model with respect to the total and slow flow. The quick flow component used in this study was taken as the difference between the total and slow flow. Model calibrations were pursued on the basis of comparing the simulated output with the observed total and slow flow using qualitative (graphical) assessments and quantitative (statistical) indicators. The study was conducted using the Soil and Water Assessment Tool (SWAT) model and a 10‐year historical record (1986–1995) of the daily flow components of the Grote Nete River basin (Belgium). The data of the period 1986–1989 were used for model calibration and data of the period 1990–1995 for model validation. The predicted daily average total flow matched the observed values with a Nash–Sutcliff coefficient of 0·67 during calibration and 0·66 during validation. The Nash–Sutcliff coefficient for slow flow was 0·72 during calibration and 0·61 during validation. Analysis of high and low flows indicated that the model is unbiased. A sensitivity analysis revealed that for the modelling of the daily total flow, accurate estimation of all 10 calibration parameters in the SWAT model is justified, while for the slow flow processes only 4 out of the set of 10 parameters were identified as most sensitive. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Minimization of environmental risk of landfill site using fuzzy logic, analytical hierarchy process, and weighted linear combination methodology in a geographic information system environment   总被引：1，自引：1，他引：0  

Abdelwaheb Aydi  Moncef Zairi  Hamed Ben Dhia 《Environmental Earth Sciences》2013,68(5):1375-1389

This paper presents a GIS-based multi-criteria site selection for municipal solid waste landfilling in Ariana Region, Tunisia. Based on the regional characteristics, literature related to disposal sites and waste management, local expert, data availability and assessments via questionnaires, 15 constraints, and 5 factors were built in the hierarchical structure for landfill suitability by multi-criteria evaluation. The factors are divided into environmental and socio-economic groups. The methodology is used for preliminary assessment of the 20-year most useful lifetime suitable landfilling sites by combining fuzzy set theory, weighted linear combination (WLC) and analytic hierarchy process (AHP) in a GIS environment. The criteria standardization is undertaken by application of different fuzzy membership functions. The fuzzy membership functions shape and their control points are chosen through assessment of expert opinion. The weightings of each selection criterion are assigned depending on the relative importance using the AHP methodology. The WLC approach is applied for alternative landfill sites prioritization. The results of this study showed five potential candidate sites, which are generated when the environmental factors are valued higher than socio-economic factors. These sites are ranked in descending order using the ELECTRE III method. However, the final decision will require further detailed geotechnical and hydrogeological analyses toward the protection of groundwater as well as surface water.  相似文献   

Implementation and evaluation of multivariate analysis for groundwater hydrochemistry assessment in arid environments: a case study of Hajeb Elyoun–Jelma, Central Tunisia     

Soumaya Hajji Kolsi  Salem Bouri  Wafik Hachicha  Hamed Ben Dhia 《Environmental Earth Sciences》2013,70(5):2215-2224

In most arid zones, groundwater (GW) is the major source of domestic, agriculture, drinking, and industrial water. Accordingly, the monitoring of its quality by different techniques and tools is a vital issue. The purpose of this paper is the evaluation of the combination of principal components analysis (PCA) and geostatistics as a technique for (1) identifying the processes affecting the groundwater chemistry of the detrital unconfined Middle Miocene Aquifer (MMA) of the Hajeb elyoun Jelma (HJ) aquifer (Tunisia) and (2) mapping the controlling variables for groundwater quality. This work is based on a limited database recorded in 22 wells tapping the aquifer and unequally distributed in the field. The proposed approach is carried out in two steps. In the first step, the application of PCA revealed that rock–water interaction, agriculture irrigation and domestic effluents could explain 85 % of the observed variability of the chemical GW quality of the MMA. As a result, two new variables are defined: V1 (rock–water interaction influence) and V2 (irrigation and domestic effluent influence). In the second step, the spatial variability of these variables over the extent of the MMA is mapped by applying a kriging interpolation technique. The results of this study suggest that, while both natural and anthropogenic processes contribute to the GW quality of the MMA, natural impacts can be considered as the most important.  相似文献   

The distribution of Kendall's tau for testing the significance of cross-correlation in persistent data     

K. H. Hamed 《水文科学杂志》2013,58(5):841-853

Abstract

Kendall's tau (τ) has been widely used as a distribution-free measure of cross-correlation between two variables. It has been previously shown that persistence in the two involved variables results in the inflation of the variance of τ. In this paper, the full null distribution of Kendall's τ for persistent data with multivariate Gaussian dependence is derived, and an approximation to the full distribution is proposed. The effect of the deviation from the multivariate Gaussian dependence model on the distribution of τ is also investigated. As a demonstration, the temporal consistency and field significance of the cross-correlation between the North Hemisphere (NH) temperature time series in the period 1850–1995 and a set of 784 NH tree-ring width (TRW) proxies in addition to 105 NH tree-ring maximum latewood density (MXD) proxies are studied. When persistence is ignored, the original Mann-Kendall test gives temporally inconsistent results between the early half (1850–1922) and the late half (1923–1995) of the record. These temporal inconsistencies are largely eliminated when persistence is accounted for, indicating the spuriousness of a large portion of the identified cross-correlations. Furthermore, the use of the modified test in combination with a field significance test that is robust to spatial correlation indicates the absence of field significant cross-correlation in both halves of the record. These results have serious implications for the use of tree-ring data as temperature proxies, and emphasize the importance of utilizing the correct distribution of Kendall's τ in order to avoid the overestimation of the significance of cross-correlation between data that exhibit significant persistence.

Citation Hamed, K. H. (2011) The distribution of Kendall's tau for testing the significance of cross-correlation in persistent data. Hydrol. Sci. J. 56(5), 841–853.  相似文献   

Investigating the influence of soil conditions and surcharge mass on seismic responses of ground surface     

Jabini Asli  Sahand  Saffari  Hamed  Saadatinezhad  Maryam 《Journal of Seismology》2021,25(5):1301-1317

Journal of Seismology - Earthquake is always known as a natural phenomenon with complex and unpredictable characteristics. One of the parameters which affects the ground motion properties is soil....  相似文献   

Dynamic stress concentration near a fluid-filled permeable borehole induced by general modal vibrations of an internal cylindrical radiator     

Seyyed M. Hasheminejad  Hamed Hosseini 《Soil Dynamics and Earthquake Engineering》2002,22(6)

Stress distribution in the vicinity of a permeable cylindrical cavity surface (borehole wall) arising due to modal vibrations of an internal cylindrical radiator of infinite extent is studied. Biot phenomenological model is used to represent the behavior of sound in the fluid-saturated elastic porous medium and closed-form solution in the form of an infinite series is developed. A numerical example for the infinite cylindrical surface excited in vibrational modes of zeroth and first order while immersed in a water-filled cavity embedded within a water-saturated Ridgefield Sandstone environment is presented and several limiting cases are examined. Effects of axial and radial vibration frequencies, porosity, frame stiffness, and interface permeability condition on stress distribution at the borehole surface are presented and discussed.  相似文献   

Application of random forest time series,support vector regression and multivariate adaptive regression splines models in prediction of snowfall (a case study of Alvand in the middle Zagros,Iran)     

Omid?Hamidi  Leili?Tapak  Hamed?Abbasi  Zohreh?MaryanajiEmail author 《Theoretical and Applied Climatology》2018,134(3-4):769-776

We have conducted a case study to investigate the performance of support vector machine, multivariate adaptive regression splines, and random forest time series methods in snowfall modeling. These models were applied to a data set of monthly snowfall collected during six cold months at Hamadan Airport sample station located in the Zagros Mountain Range in Iran. We considered monthly data of snowfall from 1981 to 2008 during the period from October/November to April/May as the training set and the data from 2009 to 2015 as the testing set. The root mean square errors (RMSE), mean absolute errors (MAE), determination coefficient (R ²), coefficient of efficiency (E%), and intra-class correlation coefficient (ICC) statistics were used as evaluation criteria. Our results indicated that the random forest time series model outperformed the support vector machine and multivariate adaptive regression splines models in predicting monthly snowfall in terms of several criteria. The RMSE, MAE, R ², E, and ICC for the testing set were 7.84, 5.52, 0.92, 0.89, and 0.93, respectively. The overall results indicated that the random forest time series model could be successfully used to estimate monthly snowfall values. Moreover, the support vector machine model showed substantial performance as well, suggesting it may also be applied to forecast snowfall in this area.  相似文献   

Impact of treated sewage sludge application on phosphorus release kinetics in some calcareous soils   总被引：1，自引：0，他引：1  

Alireza Hosseinpur  Hamed Pashamokhtari 《Environmental Geology》2008,55(5):1015-1021

Treated sewage sludge contains significant amount of phosphorus and is widely used in agriculture. Kinetics of P release in soils is a subject of importance in soil and environmental sciences. There are few studies about P release kinetics in treated sewage sludge amended soils. For this purpose, sludge was mixed with ten soils at a rate equivalent to 100 Mg sludge ha⁻¹, and P desorption was determined by successive extraction using 0.01 M CaCl₂ over a period of 65 days at 25 ± 1°C. Phosphorus release rate was rapid at first (until about first 360 h) and then became slower until equilibrium was approached. Average of P released within 360 h for the unamended and amended soils was about 65 and 73% of the total desorbed P, respectively. Zero-order, first-order, second-order, power function, simplified Elovich and parabolic diffusion law kinetics models were used to describe P release. First-order, Elovich, power function and parabolic diffusion models could well describe P release in the unamended and amended soils. Correlation coefficients between P release rate parameters and selected soil properties showed that in the control soils, calcium carbonate equivalent and Olsen-extractable P; and in the amended soils, calcium carbonate equivalent, cation exchange capacity, organic matter and Olsen-extractable P were significantly correlated with P release parameters. The results of this study showed that application of sewage sludge can change P release characteristics of soils and increase P in runoff.  相似文献   

The hydro geochemical characterization of ground waters in Tunisian Chott’s region.     

Samir Kamel  Hamed Younes  Najiba Chkir  Kamel Zouari 《Environmental Geology》2008,54(4):843-854

Tunisian Chott’s region is one of the most productive artesian basins in Tunisia. It is located in the southwestern part of the country, and its groundwater resources are developed for water supply and irrigation. The chemical composition of the water is strongly influenced by the interaction with the basinal sediments and by hydrologic characteristics such as the flow pattern and time of residence. The system is composed of an upper unconfined “Plio-Quaternary” aquifer with a varying thickness of 20–200 m, an intermediate confined/unconfined “Complex Terminal” aquifer about 100 m in thickness and a deeper “Continental Intercalaire” aquifer about 150 m in thickness separated by thick clay and marl layers. The dissolution of evaporites and carbonates explains part of the contained Na⁺, Ca²⁺, Mg²⁺, K⁺, SO₄²⁻ and Cl^-, but other processes, such carbonate precipitation, also contributes to the water composition. The stable isotope composition of waters establishes that the deep groundwater (depleted as compared to present corresponding local rainfall) is ancient water recharged probably during the late Pleistocene and the early Holocene periods. The relatively recent water in the Plio-Quaternary aquifer is composed of mixed waters resulting presumably from upward leakage from the deeper groundwater.  相似文献   

Seismic potential of the North Qazvin zone,Alborz     

Azadeh Abdollahi  Hamed Gharibdoost 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2016,10(3):213-222

The North Qazvin region is a part of the Central Alborz Mountains in Iran and has experienced destructive earthquakes. This region is a popular and industrial zone near Tehran, capital of Iran. To identify the highest and lowest seismic hazard location and consequently the seismic zonation of this region, different parameters, such as topography, geology, tectonics and seismicity, have been focused. Accordingly, the north of Qazvin region can be divided into three subzones: western, eastern and southern. Seismic activity of the western zone is higher than the other ones and seismic potential of the eastern zone is higher than the other two zones. This zoning is also necessary for all seismic active areas to find the most dangerous zone.  相似文献