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391.
392.
393.
Application of Artificial Neural Networks to Complex Groundwater Management Problems 总被引:4,自引:0,他引:4
Coppola Emery Poulton Mary Charles Emmanuel Dustman John Szidarovszky Ferenc 《Natural Resources Research》2003,12(4):303-320
As water quantity and quality problems become increasingly severe, accurate prediction and effective management of scarcer water resources will become critical. In this paper, the successful application of artificial neural network (ANN) technology is described for three types of groundwater prediction and management problems. In the first example, an ANN was trained with simulation data from a physically based numerical model to predict head (groundwater elevation) at locations of interest under variable pumping and climate conditions. The ANN achieved a high degree of predictive accuracy, and its derived state-transition equations were embedded into a multiobjective optimization formulation and solved to generate a trade-off curve depicting water supply in relation to contamination risk. In the second and third examples, ANNs were developed with real-world hydrologic and climate data for different hydrogeologic environments. For the second problem, an ANN was developed using data collected for a 5-year, 8-month period to predict heads in a multilayered surficial and limestone aquifer system under variable pumping, state, and climate conditions. Using weekly stress periods, the ANN substantially outperformed a well-calibrated numerical flow model for the 71-day validation period, and provided insights into the effects of climate and pumping on water levels. For the third problem, an ANN was developed with data collected automatically over a 6-week period to predict hourly heads in 11 high-capacity public supply wells tapping a semiconfined bedrock aquifer and subject to large well-interference effects. Using hourly stress periods, the ANN accurately predicted heads for 24-hour periods in all public supply wells. These test cases demonstrate that the ANN technology can solve a variety of complex groundwater management problems and overcome many of the problems and limitations associated with traditional physically based flow models. 相似文献
394.
Where Are Porphyry Copper Deposits Spatially Localized? A Case Study in Benguet Province,Philippines 总被引:10,自引:0,他引:10
To provide guides for exploration of porphyry copper mineralization at a district scale, we examine the spatial association between known porphyry copper deposits and geologic features in Benguet, Philippines. The spatial associations between the porphyry copper deposits and strike-slip fault discontinuities, batholithic pluton margins and porphyry plutons are quantified using weights of evidence modeling. In the training and testing district, the porphyry copper occurrences are associated spatially with strike-slip fault discontinuities, batholithic pluton margins and contacts of porphyry plutons within distances of 3 km, 2.25 km, and 1 km, respectively. In addition, the porphyry plutons are associated spatially with strike-slip fault discontinuities and contacts of batholithic plutons within a distance of 2.25 km and 3 km, respectively. Based on these significant spatial associations, predictive maps are generated to delineate zones favorable for porphyry copper mineralization and zones favorable for emplacement of porphyry plutons in Benguet province, Philippines. Validations of the predictive models demonstrate their efficacy in pointing to zones for subsequent follow-up exploration work. 相似文献
395.
396.
A Compilation of Silicon and Thirty One Trace Elements Measured in the Natural River Water Reference Material SLRS-4 (NRC-CNRC) 总被引:1,自引:0,他引:1
Delphine Yeghicheyan Jean Carignan Michel Valladon Martine Bouhnik Le Coz Florence Le Cornec Maryse Castrec-Rouelle Michel Robert Luc Aquilina Emmanuel Aubry Carine Churlaud Aline Dia Samuel Deberdt Bernard Dupré Rémi Freydier Gérard Gruau Odile Hénin Anne-Marie de Kersabiec Joël Macé Luc Marin Nicole Morin Patrice Petitjean Elodie Serrat 《Geostandards and Geoanalytical Research》2001,25(2-3):465-474
The natural river water certified reference material SLRS-4 (NRC-CNRC, National Research Council-Conseil National de Recherches Canada) has been routinely analysed for major and trace elements by six French laboratories. Most measurements were made using inductively coupled plasma-mass spectrometry. For silicon and thirty one trace elements (rare earth elements, Ag, B, Br, Cs, Ga, Ge, Li, P, Pd, Rb, Se, Th, Ti, Tl, W, Y and Zr), no certified values are assigned by NRC-CNRC. We propose some compilation values and related uncertainties according to the results obtained by the different laboratories. 相似文献
397.
Teacher''s Aide Variogram Interpretation and Modeling 总被引:13,自引:0,他引:13
The variogram is a critical input to geostatistical studies: (1) it is a tool to investigate and quantify the spatial variability of the phenomenon under study, and (2) most geostatistical estimation or simulation algorithms require an analytical variogram model, which they will reproduce with statistical fluctuations. In the construction of numerical models, the variogram reflects some of our understanding of the geometry and continuity of the variable, and can have a very important impact on predictions from such numerical models. The principles of variogram modeling are developed and illustrated with a number of practical examples. A three-dimensional interpretation of the variogram is necessary to fully describe geologic continuity. Directional continuity must be described simultaneously to be consistent with principles of geological deposition and for a legitimate measure of spatial variability for geostatistical modeling algorithms. Interpretation principles are discussed in detail. Variograms are modeled with particular functions for reasons of mathematical consistency. Used correctly, such variogram models account for the experimental data, geological interpretation, and analogue information. The steps in this essential data integration exercise are described in detail through the introduction of a rigorous methodology. 相似文献
398.
Costas Emmanuel Synolakis 《Natural Hazards》1991,4(2-3):221-234
This is a study of the application of linear theory for the estimation of the maximum runup height of long waves on plane beaches. The linear theory is reviewed and a method is presented for calculating the maximum runup. This method involves the calculation of the maximum value of an integral, now known as the runup integral. Laboratory and numerical results are presented to support this method. The implications of the theory are used to reevaluate many existing empirical runup correlations. It is shown that linear theory predicts the maximum runup satisfactorily. This study demonstrates that it is now possible to match complex offshore wave-evolution algorithms with linear theory runup solutions for the purpose of obtaining realistic tsunami inundation estimates. 相似文献
399.
Michael Anastassiades Demetrius Ilias Emmanuel Tsagakis 《Pure and Applied Geophysics》1962,51(1):142-146
Summary On November 1960 a special solar activity occured, producing characteristic disturbances in the ionosphere. Athens center followed this activity by vertical sounding and by Riometer recordings. They are evidences for proton events producing deep absorption in the ionosphere and aurora extending till 38° latitude. Some observations concerning July 1961 solar activity are reported. World wide decrease of the maximum electron density reported during the November period was observed also in Athens. Ionospheric disturbances following vertical sounding observations are of «negative» type. 相似文献
400.
Argo drifters provide information of the vertical structure in the water column and have a potential for the improvement of
understanding phytoplankton primary production and biogeochemical cycles in combination with ocean color satellite data, which
can obtain the horizontal distribution of phytoplankton biomass in the surface layer. Our examples show that using Argo drifters
with satellite-measured horizontal distribution of phytoplankton biomass at the sea surface allow an improved understanding
of the development of the spring bloom. The other possible uses of Argo drifter are discussed. 相似文献