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This research investigates the capabilities of four data-driven models, namely artificial neural network, wavelet-based artificial neural network (WANN), gene expression programming, and support vector machine, to predict water quality parameter, i.e., sodium absorption ratio (SAR) of the groundwater of the Ardabil plain, Ardabil Province, Iran. A combination of data sets including electrical conductivity, total dissolved solids, and sodium was considered as input data of the models. The models' performances were compared with the classical multiple linear regression model. The models were calibrated and validated using the measured quality data for the period of year 2005 to 2015. The performance of the models was evaluated using various statistical criteria, scatter, and PDF plots. Results showed that the data-driven models are more capable in simulating the SAR data than the classical multiple linear regression model. The WANN model provided reliable predictions of the SAR values rather than the other models. [ABSTRACT FROM AUTHOR]

This study aims to predict daily ionospheric Total Electron Content (TEC) using Gaussian Process Regression (GPR) model and Multiple Linear Regression (MLR). In this case, daily TEC values from 2015 to 2017 of two Global Navigation Satellite System (GNSS) stations were collected in Turkey. The performance of the GPR model was compared with the classical MLR model using Taylor diagrams and relative error graphs. Six models with various input parameters were performed for both GPR and MLR techniques. The results showed that although the models perform similarly, the GPR model estimated the TEC values more precisely at one and two days ahead. Therefore, the GPR model is recommended to forecast the TEC values at the corresponding GNSS stations over Turkey. [ABSTRACT FROM AUTHOR]

Reliable estimation of missing data is an important task for meteorologists, hydrologists and environment protection workers all over the world. In recent years, artificial intelligence techniques have gained enormous interest of many researchers in estimating of missing values. In the current study, we evaluated 11 artificial intelligence and classical techniques to determine the most suitable model for estimating of climatological data in three different climate conditions of Iran. In this case, 5 years (2001-2005) of observed data at target and neighborhood stations were used to estimate missing data of monthly minimum temperature, maximum temperature, mean air temperature, relative humidity, wind speed and precipitation variables. The comparison includes both visual and parametric approaches using such statistic as mean absolute errors, coefficient of efficiency and skill score. In general, it was found that although the artificial intelligence techniques are more complex and time-consuming models in identifying their best structures for optimum estimation, but they outperform the classical methods in estimating missing data in three distinct climate conditions. Moreover, the in-filling done by artificial neural network rivals that by genetic programming and sometimes becomes more satisfactory, especially for precipitation data. The results also indicated that multiple regression analysis method is the suitable method among the classical methods. The results of this research proved the high importance of choosing the best and most precise method in estimating different climatological data in Iran and other arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Groundwater level time series is a prime factor for variety of groundwater studies and is of great significance for the management of groundwater resources. Quality control of groundwater level observations is essential for hydrological applications. Artificial Intelligent techniques deal with highly nonlinear interactions and complex hydrological process and hence can be a better alternative for groundwater level prediction. In this research, the performances of Support Vector Regression (SVR) and SVR ensembled with metaheuristic Algorithm of Innovative Gunner (AIG) models were evaluated in simulating the monthly groundwater level of the Shabestar plain during the period 2001–2019. The 80 and 20% of the monthly dataset were used for training and testing the developed models. The efficiency of the developed models was compared using different statistical indices including correlation coefficient (R), Nash–Sutcliffe Efficiency (NSE) coefficient, Root-Mean-Square Error (RMSE), RMSE-observation standard deviation ratio (RSR) and Legates & McCabe's Index (ELM). The results showed that the hybrid model (SVR-AIG) generates accurate estimations in combinatory patterns. Moreover, among the SVR and SVR-AIG models with different input scenarios, the SVR-AIG model showed best results for scenario 6 (M6) in both the training stage (R = 0.995, NSE = 0.99, RMSE = 0.151 (m), RSR = 0.096 and ELM = 0.916) and the testing stage (R = 0.941, NSE = 0.879, RMSE = 0.146 (m), RSR = 0.346 and ELM = 0.660). The hybrid SVR-AIG model is shown to be more accurate and robust than the SVR models, providing a novel capability to capture unknown time-varying dependencies. In general, the results of the proposed model are promising and it provides a reliable insight for water resources planners in conducting future research of groundwater resources. [ABSTRACT FROM AUTHOR]

Accurately predicting river flows over daily timescales is considered as an important task for sustainable management of freshwater ecosystems, agricultural applications, and water resources management. In this research paper, artificial intelligence (AI) techniques, namely the cascade correlation neural networks (CCNN) and the random forest (RF) models, were employed in daily river stage and river flow prediction for two river systems (i.e., Dulhunty River and Herbert River) in Australia. To develop the CCNN and RF models, a significant 3-day antecedent river stage and river flow time series were used. 80% of the whole data were used for model training and the remaining 20% for model testing. A total of ten different model structures with different input combinations were used to evaluate the optimal model in the training phase, and the results were analyzed using statistical metrics including the root mean square error (RMSE), Nash–Sutcliffe coefficient (NS), Willmott's index of agreement (WI), and Legate and McCabe's index (ELM) in the testing phase. The inter-comparison of CCNN and RF models for both river systems showed that the CCNN model was able to generate a more accurate prediction of the river stage and river flow compared to the RF model. Due to hydro-geographic differences leading to a different underlying historical data characteristics, the optimal CCNN's performance for the Dulhunty River was found to be most accurate, in terms of ELM = 0.779, WI = 0.964, and ENS = 0.862 versus 0.775, 0.968, and 0.885 for the Herbert River. Following the performance accuracies, the authors ascertained that the CCNN model can be taken as a preferred data intelligent tool for river stage and river flow prediction. [ABSTRACT FROM AUTHOR]

The barriers for the development of continuous monitoring of Suspended Sediment Concentration (SSC) in channels/rivers include costs and technological gaps but this paper shows that a solution is feasible by: (i) using readily available high-resolution images; (ii) transforming the images into image analytics to form a modelling dataset; and (iii) constructing predictive models by learning inherent correlation between observed SSC values and their image analytics. High-resolution images were taken of water containing a series of SSC values using an exploratory flume. Machine learning is processed by dividing the dataset into training and testing sets and the paper uses the following models: Generalized Linear Machine (GLM) and Distributed Random Forest (DRF). Results show that each model is capable of reliable predictions but the errors at higher SSC are not fully explained by modelling alone. Here we offer sufficient evidence for the feasibility of a continuous SSC monitoring capability in channels before the next phase of the study with the goal of producing practice guidelines. [ABSTRACT FROM AUTHOR]