Radial basis function neural network for hydrologic inversion: an appraisal with classical and spatio-temporal geostatistical techniques in the context of site characterization   总被引：2，自引：0，他引：2  

Amvrossios C. Bagtzoglou  Faisal Hossain 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(7):933-945

This paper investigates three techniques for spatial mapping and the consequential hydrologic inversion, using hydraulic conductivity (or transmissivity) and hydraulic head as the geophysical parameters of concern. The data for the study were obtained from the Waste Isolation and Pilot Plant (WIPP) site and surrounding area in the remote Chihuahuan Desert of southeastern New Mexico. The central technique was the Radial Basis Function algorithm for an Artificial Neural Network (RBF-ANN). An appraisal of its performance in light of classical and temporal geostatistical techniques is presented. Our classical geostatistical technique of concern was Ordinary Kriging (OK), while the method of Bayesian Maximum Entropy (BME) constituted an advanced, spatio-temporal mapping technique. A fusion technique for soft or inter-dependent data was developed in this study for use with the neural network. It was observed that the RBF-ANN is capable of hydrologic inversion for transmissivity estimation with features remaining essentially similar to that obtained from kriging. The BME technique, on the other hand, was found to reveal an ability to map localized lows and highs that were otherwise not as apparent in OK or RBF-ANN techniques.  相似文献   

Prediction of wind properties in urban environments using artificial neural network   总被引：2，自引：2，他引：0  

Kapil Varshney  Kamal Poddar 《Theoretical and Applied Climatology》2012,108(3-4):579-590

Artificial neural network (ANN) modeling has been performed to predict turbulent boundary layer characteristics for rough terrain based on experimental tests conducted in a boundary-layer wind tunnel to simulate atmospheric boundary layer using passive roughness devices such as spires, barriers, roughness elements on the floor, and slots in the extended test section. Different configurations of passive devices assisted to simulate urban terrains. A part of the wind tunnel test results are used as training sets for the ANN, and the other part of the test results are used to compare the prediction results of the ANN. Two ANN models have been developed in this study. The first one has been used to predict mean velocity, turbulence intensity, and model length scale factor. Results show that ANN is an efficient, accurate, and robust modeling procedure to predict turbulent characteristics of wind. In particular, it was found that the ANN-predicted wind mean velocities are within 4.7%, turbulence intensities are within 6.2%, and model length scale factors are within 3.8% of the actual measured values. In addition, another ANN model has been developed to predict instantaneous velocities that enables calculating the power spectral density of longitudinal velocity fluctuations. Results show that the predicted power spectra are in a good agreement with the power spectra obtained from measured instantaneous velocities.  相似文献   

Area Change and Thickness Variation over Pensilungpa Glacier (J&;K) using Remote Sensing     

Arvind Chandra Pandey  Swagata Ghosh  M. S. Nathawat  Reet Kamal Tiwari 《Journal of the Indian Society of Remote Sensing》2012,40(2):245-255

Accurate representations of the Earth’s surface in the form of digital elevation models (DEMs) are essential for a variety of applications in glaciological and remote-sensing research. In the present study area change and thickness variation over Pensilungpa glacier was attempted using remote sensing approach. It can be remarked that a net loss of 9.23 sq. km. which is 38% of the glacier area mapped in 1962 indicate a drastic change over the glacier area during 1962–2007. Estimation of glacier thickness change on Pensilungpa glacier based on ASTER DEM (2003) and Survey of India (SOI) contour based DEM (1962) indicated increase in the glacier elevation in the accumulation zone mainly by 30 to 90 m and similar reduction by 30 to 90 m in the ablation zone.  相似文献   

Groundwater management scenarios for the Biyadh-Wasia aquifer systems in the eastern part of Riyadh region,Saudi Arabia     

Hussain J. Alfaifi  Mohammed S. Abdelfatah  Kamal Abdelrahman  Faisal K. Zaidi  Elkhedr Ibrahim  Nassir S. Alarifi 《Journal of the Geological Society of India》2017,89(6):669-674

Groundwater stored in the deep seated sedimentary aquifers is the most important source of water supply. The lack of sufficient groundwater recharge and the overdependence on groundwater might lead to unavailability of this precious natural resource if proper management practices are not adopted. Finite difference modelling using the MODFLOW program was carried out in the east of Riyadh city to simulate the groundwater level conditions under different abstraction scenarios. The simulated aquifer system combines the Wasia and Biyadh aquifer (composed of sandstone) and Aruma aquifer (limestone) which lies between 24°30'00"- 25°30'00" N and longitudes 47°00'00"- 48°00'00"E. The transmissivity and storage coefficient values of Biyadh aquifer are 7.0x10^-3 to 7.0x10^-2 m²/day and 3.7x10^-4 to 9.4x10^-4 respectively. The transmissivity and storage coefficient values of Wasia aquifer ranges from 6.7x10^-3 to 8.5x10^-2 m²/day and 2x10^-4 to 2.3x10^-4 respectively. The model calibration involved altering the values of model input parameters to match field conditions within certain acceptable limits to forecast the aquifer response over a period of 35 years (2015-2050). The modelling grid consisted of 20 and 24 columns with the grids spacing of 4 km for the small grids and 6 km for large grids. The results showed that though the Wasia aquifer was productive, it showed a large decline in water levels if water abstraction continued at the present rate. If the existing trends of groundwater withdraw continues; the piezometric heads in Wasia and Biyadh aquifers will decline by the year 2050. A reduction in 25% of the existing groundwater pumping rate in the well field will minimize the rate of groundwater decline in the aquifer to a considerable extent.  相似文献   

Seismic risk assessment at the proposed site of Gemsa wind power station,southwestern coast of Gulf of Suez,Egypt     

Kamal Abdelrahman  Abdullah Al-Amri  Nassir Al-Arifi  Enayat Abdelmoneim 《Journal of the Geological Society of India》2017,89(2):192-196

Gemsa has been chosen as the site for one of a new generation of power stations along the south-western margin of the Gulf of Suez. This site has been affected by a number of destructive earthquakes (M_w> 5), in addition to large number of earthquakes with magnitudes of less than 5. In this study seismic activities in the region were collected and re-evaluated, and the main earthquake prone zones were identified. It is indicated that this site is affected by the southern Gulf of Suez, northern Red Sea and Gulf of Aqaba source zones. The southern Gulf of Suez source zone is the nearest to the proposed site. The stochastic simulation method has been applied to estimate the Peak GroundAcceleration at the site of the proposed Gemsa power plant. It was noticed that the pseudo-spectral acceleration (PSA) reaches 175 cm/sec2 resulting from the southern Gulf of Suez seismic source. In addition, the response spectrum was conducted with a damping value of 5% of the critical damping, and the predominant period reached 0.1sec at the site. These results should be taken into consideration by civil engineers and decision-makers for designing earthquake resistant structures.  相似文献   

Continental rift-setting and evolution of Neoproterozoic Sindreth Basin in NW-India     

Stefan Schöbel  Kamal K Sharma  Thorsten Hörbrand  Theresa Böhm  Ines Donhauser  Helga de Wall 《Journal of Earth System Science》2017,126(6):90

The Neoproterozoic Sindreth Basin, NW India, and its surrounding area represent a half graben structure situated between the undeformed Malani Igneous Suite (MIS) in the west and a corridor of coeval Cryogenian ductile deformation, anatexis and granite intrusion in the east. The main lithologies observed in the basin are conglomerate, fanglomerate, debris flow and lake deposits derived from a nearby continental provenance, intercalated with concurrent mafic and felsic lava flows. Based on geological traverses across the strike of the basin, we propose a three-fold classification comprising Lower Clastic Unit and an Upper Clastic Unit and a Bimodal (basalt–rhyolite) Volcanic Unit separating the two. Tilting due to basin inversion and faulting has been observed; however, the rocks are unmetamorphosed and show undisturbed primary sedimentary features. The stratigraphic record of the basin is characteristic for deposition and magmatism in a fault-related continental setting. Implications of the findings have been discussed in the context of Neoproterozoic crustal dynamics in NW India. This study provides conclusive evidence for a continental setting for Sindreth Basin evolution and contests the recent models of active subduction setting (either back-arc basin or accretionary sediments over a subduction zone).  相似文献   

Environmental assessment of soil,groundwater, and surface water quality in the south of the Riyadh,Saudi Arabia     

Abeer. Sh. Salman  Ali Al Dosari  Faisal K. Zaidi  Oumar Allafouza Loni 《Arabian Journal of Geosciences》2017,10(22):490

To understand the impact of the influence of treated wastewater, a study was undertaken in the downstream side of Wadi Hanifa in the southern part of Riyadh City in Saudi Arabia. Chemical elements from 17 groundwater samples, 9 surface water samples (treated wastewater), and 14 soil samples were analyzed. Water facies analyses showed that both groundwater and surface water belong to the SO₄-Cl class. However, the groundwater is characterized by high salinity (average value of 3547 mg/l), which may be result of the greater rock-water interaction and limited rainfall recharge. The NO₃ values are also high in the groundwater samples (average value of 40 mg/l) and are mainly attributed to the agricultural practices in the study area. The surface water samples (treated wastewater from the plant) shows an average salinity value of 1232 mg/l and is better suited for irrigation purposes. Heavy elements analyzed in the soil samples show high concentrations of all the elements except Mn and Ni as compared to their background concentration. Enrichment factor and index of geoaccumulation calculated from the soil samples indicate that they are severely enriched with respect to Cd and Se. The spatial distribution maps were prepared based on kriging interpolation technique to estimate the concentrations of the analyzed elements at unknown locations. The treated wastewater in the study area is better suited for agricultural and domestic activities as compared to groundwater.  相似文献   

Syncline contribution to mountain peak building: examples from Western Zagros,Kurdistan Region,Northeastern Iraq     

Kamal Haji Karim  Polla Azad Khanaqa 《Arabian Journal of Geosciences》2017,10(16):375

The current study focuses on roles of the synclines in building mountains of the Zagros Fold-Thrust Belt from Northeastern Iraq, Kurdistan Region. The studied area is located in the Imbricated Zone, which is a continuation of Simply Folded Zone of Iran. In some parts of this zone, the synclines contribute to building nearly half of the mountains and increase the relief contrast of the landscapes. The role of syncline in building mountains is opposite to its apparent intrinsic shape which is located in low land and normally forms synclinal valleys. In studied area, this phenomenon is observable in the areas that are complexly deformed, deeply exhumed, and predominately composed of the carbonate rocks. In these areas, exhumation and stream erosion have removed high thickness of overburden rocks and the tectonic stresses have crenulated carbonate rocks in the synclines. Due to these processes, these synclines are observable on the peak of the mountains now. The contribution of synclines in mountain building is related to three properties: the first is folding of synclines in confined condition (relative to anticlines) by which they have transformed to highly compact and stiff rocks. The second is accumulation of hydrothermal or meteoric water in the synclines due to its downward bending which aids precipitation of minerals and heals the possible tectonically and lithostatically induced fractures. The third is ductile deformation of synclines in confined and deeper level as compared to brittle deformation of anticlines in relatively shallower level and unconfined condition during deformation. Consequently, these factors result in an inversion of topography by which synclines are remained as mountains (high topography) above surface during exhumation while erosion removes anticlines. The result of this study is applicable for geological, geomorphological, and structural mapping in highly deformed and deeply exhumed terrains. The possible prediction of geomorphological position of synclines and anticlines on the mountain peaks and valley bottoms respectively is the applicable result in the above terrains.  相似文献   

Body Wave Crustal Attenuation Characteristics in the Garhwal Himalaya,India     

Sanjay S. Negi  Ajay Paul  Anand Joshi  Kamal 《Pure and Applied Geophysics》2015,172(6):1451-1469

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Steered migration in hard rock environments          下载免费PDF全文

Konstantin Tertyshnikov  Roman Pevzner  Andrej Bóna  Faisal Alonaizi  Boris Gurevich 《Geophysical Prospecting》2015,63(3):525-533

Hard rock seismic exploration normally has to deal with rather complex geological environments. These types of environments are usually characterized by a large number of local heterogeneity (e.g., faults, fracture zones, and steeply dipping interfaces). The seismic data from such environments often have a poor signal‐to‐noise ratio because of the complexity of hard rock geology. To be able to obtain reliable images of subsurface structures in such geological conditions, processing algorithms that are capable of handling seismic data with a low signal‐to‐noise ratio are required for a reflection seismic exploration. In this paper, we describe a modification of the 3D Kirchhoff post‐stack migration algorithm that utilizes coherency attributes obtained by the diffraction imaging algorithm in 3D to steer the main Kirchhoff summation. The application to a 3D synthetic model shows the stability of the presented steered migration to the presence of high level of the random noise. A test on the 3D seismic volume, acquired on a mine site located in Western Australia, reveals the capability of the approach to image steep and sharp objects such as fracture and fault zones and lateral heterogeneity.  相似文献