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The transient electromagnetic response due to a pair of horizontal conducting sheets induced by a loop field is obtained. The response characteristics in the three different regions (above the upper sheet, between the two sheets and below the lower sheet) are briefly discussed. In the first and second regions the composite response is characterised by an overburden response asymptote during early times and a target response asymptote during late times. The transition zones are characterised by shoulder-like bends. In the third region, the composite response increases in direct proportion to the induction number, eventually merging with the target response for large values of the induction number.  相似文献   
2.
Over the past few decades, groundwater has become an essential commodity owing to increased demand as a result of growing population, industrialization, urbanization and so on. The water supply situation is expected to become more severe in the future because of continued unsustainable water use and projected change in hydrometeorological parameters due to climate change. This study is based on the integrated approach of remote sensing, geographical information system and multicriteria decision‐making techniques to determine the most important contributing factors that affect the groundwater resources and to delineate the groundwater potential zones. Ten thematic layers, namely, geomorphology, geology, soil, topographic elevation (digital elevation model), land use/land cover, drainage density, lineament density, proximity of surface water bodies, surface temperature and post‐monsoon groundwater depth, were considered for the present study. These thematic layers were selected for groundwater prospecting based on the literature; discussion with the experts of the Central Ground Water Board, Government of India; field observations; geophysical investigation; and multivariate techniques. The thematic layers and their features were assigned suitable weights on Saaty's scale according to their relative significance for groundwater occurrence. The assigned weights of the layers and their features were normalized by using the analytic hierarchy process and eigenvector method. Finally, the selected thematic maps were integrated using a weighted linear combination method to create the final groundwater potential zone map. The final output map shows different zones of groundwater potential, namely, very good (16%), good (35%), moderate (28%) low (17%) and very low (2.1%). The groundwater potential zone map was finally validated using the discharge and groundwater depth data from 28 and 98 pumping wells, respectively, which showed good correlation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
3.
Water is a fluctuating resource making it difficult to measure in time and in space. To demonstrate the efficiency of the geographic information system (GIS) for groundwater studies, information on the parameters controlling groundwater such as lithology, geomorphology and lineament analysis were analyzed. LISS-III and Landsat satellite image of the area was used to infer information on the geologic lineaments and geomorphology. To delineate linear features enhancement and direction, filtering was performed on single bands of Landsat images. Thematic maps for geology, slope, geomorphology and lineament were prepared and integrated in GIS by assigning the weights and ranking to various parameters controlling the occurrence of groundwater to generate the groundwater potential map for the study area. The results indicate that the floodplain of river and its adjoining areas have very good groundwater potential, whereas the steeply sloping area in the northern part having high relief and slope possesses poor groundwater potential.  相似文献   
4.
Groundwater exploitation in Punjab has increased in last few decades due to rapid increase in industrialization, population, crop production, and erratic monsoon. In the present study, groundwater samples from 29 locations were collected and analyzed for almost all major anions, cations, and heavy metals. The analyzed parameters formed the attribute database for statistical analysis. The study approach included multivariate statistical analysis of hydro-chemical data to identify hydro-geochemical processes occurring in the study area and its relation to groundwater quality. The principal component analysis produced seven significant factors that explained nearly 77 % of the cumulative variance. Factor 1 explained nearly 22.05 % of dataset with variables loading indicating mineralization of geological component of soil. Trilinear plot and other graphical methods were also used to identify chemical facies of groundwater and geochemical processes occurring in study area. The water type in the study area is of Na/K–Mg–HCO3 type. It was found that the general hydro-geochemistry of groundwater in the study area dominated is by the processes such as carbonate/silicate weathering, ion-exchange, and dissolution. Thus, statistical methods can prove to be an effective tool understanding hydro-geochemistry of a region along with conventional graphical methods.  相似文献   
5.
Effect of canal on land use/land cover using remote sensing and GIS   总被引：3，自引：0，他引：3  
The monitoring of land use/land covers (LULCs) is an indispensable exercise for all those involved in executing policies to optimize the use of natural resources and minimize the ill impacts on the environment. The study here aims at analyzing the changes that occurred in LULC over a time span from 1990 to 2005 using multi date data of a part of Punjab. The digital data consisted of two sets of Landsat Thematic Mapper (TM) data and one set of IRS-1C data. Utilizing hybrid classification technique for interpretation and on field validation, it has been found that canal irrigation leads to changes in LULC as there is a change in cropping pattern as well as increase in water logged area.  相似文献   
6.
The dependency of people on groundwater has increased in the past few decades due to tremendous increase in crop production, population and industrialization. Groundwater is the main source of irrigation in Shiwaliks of Punjab. In the present study the samples were collected from predetermined location as was located on satellite image on basis of spectral reflectance. Global positioning system was used to collect samples from specific locations. Principal components analysis (PCA) together with other factor analysis procedures consolidate a large number of observed variables into a smaller number of factors that can be more readily interpreted. In the present study, concentrations of different constituents were correlated based on underlying physical and chemical processes such as dissociation, ion exchange, weathering or carbonate equilibrium reactions. The PCA produced six significant components that explained 78% of the cumulative variance. The concentration of the few trace metals was found to be much higher indicating recharge due to precipitation as main transport mechanism of transport of heavy metals in groundwater which is also confirmed by PCA. Piper and other graphical methods were used to identify geochemical facies of groundwater samples and geochemical processes occurring in study area. The water in the study area has temporary hardness and is mainly of Ca–Mg–HCO3 type.  相似文献   
7.
The current study focuses on the vertical profile of different geochemical fractions of phosphorus-loosely bound(Lo–P),aluminium bound(Al–P),iron bound(Fe–P),calcium bound(Ca–P),and organic bound phosphorus(O–P)along with ecological risk assessment of sediment cores from Chilika Lake,eastcoast of India.The percentage contribution of the different fractions to the sedimentary phosphorus in the sediment column of the whole lake are on the order:O–P(33.2%)>Ca–P(20.3%)>Fe–P(18%)>Al–P(6.7%)>Lo–P(0.35%).The Phosphorus Pollution Index(PPI)revealed the contamination of lake sediment with phosphorus.The principal component and cluster analyses highlighted the anthropogenic contribution of phosphorus.The negative loading of Ca–P with Ca points towards its origin from marine shells.The discriminate analysis showed that the variables like Ca–P,bio-available phosphorus(BAP),and pH were able to effectively discriminate the sectors in a significant manner.  相似文献   
8.
The use of remote sensing data with other ancillary data in a geographic information system (GIS) environment is useful to delineate groundwater potential zonation map of Ken–Betwa river linking area of Bundelkhand. Various themes of information such as geomorphology, land use/land cover, lineament extracted from digital processing of Landsat (ETM+) satellite data of the year 2005 and drainage map were extracted from survey of India topographic sheets, and elevation, slope data were generated from shuttle radar topography mission (SRTM) digital elevation model (DEM). These themes were overlaid to generate groundwater potential zonation (GWPZ) map of the area. The final map of the area shows different zones of groundwater prospects, viz., good (5.22% of the area), moderate (65.83% of the area) poor (15.31% of the area) and very poor (13.64% of area).  相似文献   
9.
Summary In this note the deflection of a simply supported rectangular elastic plate on viscoelastic foundation has been obtained due to a moving load.  相似文献   
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