Intercomparison of High-Resolution Bay of Bengal Circulation Models Forced with Different Winds     

Atul Srivastava  Suneet Dwivedi  Alok Kumar Mishra 《Marine Geodesy》2016,39(3-4):271-289

The high-resolution Bay of Bengal circulation modeling in the region [80E–95E; 5N–22N] is performed with a horizontal resolution of 10 km and the highest vertical resolution of 5 m near the surface. The intercomparison experiments, with ocean model forced with the near-surface (1) National Centers for Environmental Prediction (NCEP) reanalysis winds and (2) blended seawinds data (a combination of remotely sensed scatterometer and in situ observations) are carried out for a period of 17 years during 1998–2014. The seasonal variability of the realistically simulated surface hydrographic (temperature and salinity) and circulation (currents) variables from both the experiments is compared and contrasted with the observational data. The mixed layer depth seasonal variability of the region is also studied. The mesoscale features of currents at 50 and 100 m are also studied. The volume transport across different sections in the Bay of Bengal is computed and its relation with summer monsoon rainfall is investigated. The results suggest that there is no real advantage of using high-resolution blended seawinds over the much coarser NCEP reanalysis winds.  相似文献   

Monitoring Tamil Nadu flood of 2015 using satellite remote sensing     

Anoop Kumar Mishra 《Natural Hazards》2016,82(2):1431-1434

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Numerical Study of Mine Site Specific Multiseam Mining and Its Impact on Surface Subsidence and Chain Pillar Stress     

Manoj Khanal  Deepak Adhikary  Chandana Jayasundara  Rao Balusu 《Geotechnical and Geological Engineering》2016,34(1):217-235

This paper investigates various multiseam mining related parameters using mine site specific data and numerical simulations. Two important mining effects—subsidence and stress—are analysed for different possible mining layouts. A geological mine dataset has been used to generate a numerical model. The predicted surface subsidence magnitude and surface profile have been compared under different scenarios to assess potential options in multiseam mining strategies. The effects that seam separation distances, mining offset, panel layout and panel orientation each have on surface subsidence and chain pillar stress magnitude have been investigated. The numerical simulation shows that ascending or descending mining directions have little impact on controlling the surface subsidence in multiseam mining and predicted an almost identical maximum stress development at the chain pillars. Numerical simulations infer that the orientation of the top panels control the subsidence profile.  相似文献   

Cyclone and monsoonal wave characteristics of northwestern Bay of Bengal: long-term observations and modeling     

Sisir Kumar Patra  Pravakar Mishra  P. K. Mohanty  U. K. Pradhan  U. S. Panda  M. V. Ramana Murthy  V. Sanil Kumar  T. M. Balakrishnan Nair 《Natural Hazards》2016,81(2):1051-1071

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Modeling urban floods and drainage using SWMM and MIKE URBAN: a case study     

Deepak Singh Bisht  Chandranath Chatterjee  Shivani Kalakoti  Pawan Upadhyay  Manaswinee Sahoo  Ambarnil Panda 《Natural Hazards》2016,84(2):749-776

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Crustal structure in the North Arabian Sea from magnetic surveys     

D. C. Mishra 《Marine Geophysical Researches》1981,4(4):427-436

The spectral study of the aero-magnetic map of the North Arabian Sea (above 20°N) has delineated three horizons at average depths of 45 km, 21 km, and 8 km. Spectral estimates from smaller blocks of data drawn from the original map suggest that the 21 km horizon varies in depth from 14 km on the abyssal plain (oceanic crust) to 24 km towards the north and 28 km towards the east onto the continental shelf. This appears to correspond to the crust-mantle interface (Moho). The 8 km horizon corresponds to the top of the igneous basement. The significance of the deepest layer (45 km) is discussed as the maximum depth of the Curie point geotherm in this region. The spectral estimate of the block of data on the continental shelf off the west coast of India (above 20°N) has brought out some magnetic inhomogeneity at a shallower depth of 4 km. This appears to be connected with the sea-floor spreading phenomenon from the Carlsberg ridge. The presence of such a magnetic inhomogeneity at a depth of 4 km is further confirmed by the spectral estimate of a marine magnetic map off the west coast of India around Bombay. The depth of the basement inferred from this study is in close agreement with that obtained from other studies in this region, such as seismics.  相似文献   

Catchment area‐based evaluation of the AMC‐dependent SCS‐CN‐based rainfall–runoff models     

S. K. Mishra  M. K. Jain  R. P. Pandey  V. P. Singh 《水文研究》2005,19(14):2701-2718

Using a large set of rainfall–runoff data from 234 watersheds in the USA, a catchment area‐based evaluation of the modified version of the Mishra and Singh (2002a) model was performed. The model is based on the Soil Conservation Service Curve Number (SCS‐CN) methodology and incorporates the antecedent moisture in computation of direct surface runoff. Comparison with the existing SCS‐CN method showed that the modified version performed better than did the existing one on the data of all seven area‐based groups of watersheds ranging from 0·01 to 310·3 km². Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

A study on the occurrence of flood events over Jammu and Kashmir during September 2014 using satellite remote sensing     

Anoop Kumar Mishra 《Natural Hazards》2015,78(2):1463-1467

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Seasonal and spatial variations in the scaling and correlation structure of streamflow data     

Mehmet Özger  Ashok K. Mishra  Vijay P. Singh 《水文研究》2013,27(12):1681-1690

Seasonal and spatial variability in scaling, correlation and wavelet variance parameter of daily streamflow data were investigated using 56 gauging stations from five basins located in two different climate zones. Multifractal temporal scaling properties were detected using a multiplicative cascade model. The wavelet variance parameter yielded persistence properties of the streamflow time series. Seasonal variations were found to be significant in that winter and spring seasons where large‐scale frontal events are dominant showed higher long‐term correlations and less multifractality than did summer and fall seasons. Coherent spatial variations were apparent. The Neches River basin located in a subtropic humid climate zone exhibited high persistence and long‐term correlation as well as less multifractality as compared with other basins. It is found that larger drainage areas tend to have smaller multifractality and higher persistence structure, and this tendency becomes apparent in regions that receive large amounts of precipitation and decreases towards arid regions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Effect of general loss-cone distribution function on electrostatic ion-cyclotron instability in an inhomogeneous plasma: particle aspect analysis     

Ruchi Mishra  M. S. Tiwari 《Earth, Moon, and Planets》2007,100(3-4):195-214

The electrostatic ion-cyclotron instability (EICI) in low β (ratio of plasma to magnetic pressure), anisotropic, inhomogeneous plasma is studied by investigating the trajectories of the particles using the general loss-cone distribution function (Dory-Guest-Harris type) for the plasma ions. In particular, the role of the loss-cone feature as determined by the loss-cone indices, in driving the drift-cyclotron loss-cone (DCLC) instability is analysed. It is found that for both long and short wavelength DCLC mode the loss-cone indices and the perpendicular thermal velocity affect the dispersion equation and the growth rate of the wave by virtue of their occurrence in the temperature anisotropy. The dispersion relation for the DCLC mode derived here using the particle aspect analysis approach and the general loss-cone distribution function considers the ion diamagnetic drift and also includes the effects of the parallel propagation and the ion temperature anisotropy. It is also found that the diamagnetic drift velocity due to the density gradient of the plasma ions in the presence of the general loss-cone distribution acts as a source of free energy for the wave and leads to the generation of the DCLC instability with enhanced growth rate. The particle aspect analysis approach used to study the EICI in inhomogeneous plasma gives a fairly good explanation for the particle energisation, wave emission by the wave–particle interaction and the results obtained using this particle aspect analysis approach are in agreement with the previous theoretical findings using the kinetic approach.  相似文献