Boundary element method for analyzing flow through a random semiconfined aquifer     

Y. Xiang  M. G. Satish  L. G. Jaeger 《Stochastic Hydrology and Hydraulics》1992,6(2):81-88

With the aid of perturbation technique a boundary element procedure is developed for solution of two-dimensional Helmholtz equation with a random parameter of small variability. The perturbation boundary element method does not require specification of probability density function of the parameter but only its mean and standard deviation. The method is used to analyze steady-state groundwater flows in a horizontal shallow semiconfined aquifer (homogeneous and isotropic) of probabilistic properties. To illustrate the applicability of the method, a simple numerical example is presented. As the nature of perturbation method suggests, the developed method is valid only when the perturbed value of the parameter is of a small order.  相似文献   

Diurnal and semidiurnal tidal currents in the deep mid-Arabian Sea     

S. S. C. Shenoi  A. D. Gouveia  S. R. Shetye 《Journal of Earth System Science》1992,101(2):177-189

Current meter records from two depths, approximately 1000 and 3000 m, at three moorings in the deep mid-Arabian Sea were used to study tidal components. Tidal ellipses for the semi-diurnal (M₂, S₂ and K₂) and the diurnal (K₁, and P₁) tidal constituents have been determined using the currents recorded at hourly intervals during May 1986–May 1987. The clockwise rotating M₂ tidal currents were the strongest. The maximum horizontal velocities due to M₂,₂ and K₁ tides were 2.2 cm/s, l.0cm/s and 0.89 cm/s respectively. The amplitudes of the other two constituents (P₁, and K₂) were much smaller. The barotropic M₂ ellipses have been estimated by averaging the M₂ tidal currents at the upper and lower levels. Although the amplitudes of computed ellipses are lower than those that have been predicted using numerical models of global tidal model, their orientations are the same.  相似文献   

Boundary element method for analyzing flow through a random semiconfined aquifer     

Y. Xiang  M. G. Satish  L. G. Jaeger 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(2):81-88

With the aid of perturbation technique a boundary element procedure is developed for solution of two-dimensional Helmholtz equation with a random parameter of small variability. The perturbation boundary element method does not require specification of probability density function of the parameter but only its mean and standard deviation. The method is used to analyze steady-state groundwater flows in a horizontal shallow semiconfined aquifer (homogeneous and isotropic) of probabilistic properties. To illustrate the applicability of the method, a simple numerical example is presented. As the nature of perturbation method suggests, the developed method is valid only when the perturbed value of the parameter is of a small order.  相似文献   

Seasonal variation of the salinity in the Zuari estuary,Goa, India     

S. R. Shetye  C. S. Murty 《Journal of Earth System Science》1987,96(3):249-257

The annual salt budget of the Zuari is examined. The characteristics of the estuary differ markedly from the low run off season during November–May to the heavy run off period of the southwest monsoon from June to October. During November–May the estuary is vertically mixed and the two processes controlling the transport of salt are run off induced advective transport out of the estuary, and tidally induced diffusive transport into the estuary. The magnitude of the latter is about 20% larger, leading to a salinity rise in the estuary. The diffusion coefficient has been estimated to be 233 ± 101 m²/sec. With the onset of the southwest monsoon, the run off increases dramatically, and the estuary loses about 75% of its salt during the first two months of the season. About 2/3 of this loss is recovered in the next two months when the run off decreases. Because the estuary is partially stratified during June–October, gravitational circulation is expected to play a role in addition to tidal diffusion and run off. The magnitude of its contribution has, however, not yet been determined.  相似文献   

Monthly-mean wind stress along the coast of the north Indian Ocean     

Satish R Shetye  S Satheesh Chandra Shenoi  M K Antony  V Krishna Kumar 《Journal of Earth System Science》1985,94(2):129-137

Monthly-mean wind stress and its longshore and offshore components have been computed using the bulk aerodynamic method for each of a string of 36 two-degree-latitude by two-degree-longitude squares along the coast of the north Indian Ocean. The data source for the computation is the sixty-year mean resultant winds of Hastenrath and Lamb. The main features exhibited by the components, taking the longshore components as positive (negative) when the Ekman transport is away from (towards) the coast, are: (1) Along the coasts of Somalia and Arabia, the magnitude of the wind stress is among the highest in the north Indian Ocean, and its direction is generally parallel to the coastline. This results in a longshore component which is large (as high as 2·5 dyne/cm²) and positive during the southwest monsoon, and weaker (less than 0·6 dyne/cm²) and negative during the northeast monsoon. (2) Though weak (less than 0·2 dyne/cm²) during the northeast monsoon, the monthly-mean longshore component along the west coast of India remains positive throughout the year. The magnitude of the offshore component during the southwest monsoon is much larger than that of the longshore component. (3) The behaviour of the wind stress components along the east coast of India is similar to that along the Somalia-Arabia coast, but the magnitudes are much smaller.  相似文献   

Stability analysis of slope with building loads     

D.K. Paul  Satish Kumar 《Soil Dynamics and Earthquake Engineering》1997,16(6):395-405

In hill areas, landslides are frequent and hazardous. In developing hill areas, many multistoreyed r.c.c. farmed buildings are constructed on hill slope. The building loads are transferred to the hill slope terrain at the foundation level, which may cause hill slope failure. Therefore the stability of hill slope with building loads needs to be checked. In this paper, a procedure has been developed to find the factor of safety against sliding failure of slope considering building loads transferred to the slope. Earthquake forces can also be considered in the analysis. Different types of soils in the slope can be considered. A computer program has been developed based on the formulation presented in the paper and is validated by solving few examples. Stability of slope with differently configured buildings have been studied. Provisions to be made for stepped foundations on hill slopes has been highlighted here.  相似文献   

Determination of Poisson's ratio from pre-critical wide-angle seismic reflection data from the BABEL project     

Adam Law  David B. Snyder  Satish C. Singh 《Geophysical Journal International》1995,122(1):16-32

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Demarcating saline water intrusion pathways using remote sensing,GIS and geophysical techniques in structurally controlled coastal aquifers in Southern India     

Ratnakar Dhakate  S. Sankaran  V. Satish Kumar  B. Amarender  P. Harikumar  S. K. Subramanian 《Environmental Earth Sciences》2016,75(5):363

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Fuzzy–frequency ratio model for avalanche susceptibility mapping     

Satish Kumar  Snehmani  Pankaj Kumar Srivastava  Akshay Gore  Mritunjay Kumar Singh 《International Journal of Digital Earth》2016,9(12):1168-1184

Avalanche activities in the Indian Himalaya cause the majority of fatalities and responsible for heavy damage to the property. Avalanche susceptibility maps assist decision-makers and planners to execute suitable measures to reduce the avalanche risk. In the present study, a probabilistic data-driven geospatial fuzzy–frequency ratio (fuzzy–FR) model is proposed and developed for avalanche susceptibility mapping, especially for the large undocumented region. The fuzzy–FR model for avalanche susceptibility mapping is initially developed and applied for Lahaul-Spiti region. The fuzzy–FR model utilized the six avalanche occurrence factors (i.e. slope, aspect, curvature, elevation, terrain roughness and vegetation cover) and one referent avalanche inventory map to generate the avalanche susceptibility map. Amongst 292 documented avalanche locations from the avalanche inventory map, 233 (80%) were used for training the model and remaining 59 (20%) were used for validation of the map. The avalanche susceptibility map is validated by calculating the area under the receiver operating characteristic curve (ROC-AUC) technique. For validation of the results using ROC-AUC technique, the success rate and prediction rate were calculated. The values of success rate and prediction rate were 94.07% and 91.76%, respectively. The validation of results using ROC-AUC indicated the fuzzy–FR model is appropriate for avalanche susceptibility mapping.  相似文献   

Reconciling droughts and landfalling tropical cyclones in the Southeastern United States     

Vasubandhu Misra  Satish Bastola 《Climate Dynamics》2016,46(3-4):1277-1286

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