Hydrographical characteristics and oxygen isotopic signatures of water in a coastal environment (Mangalore) along the southeastern Arabian Sea     

Josia Jacob  Prosenjit Ghosh  A. P. Dineshbabu  P. Sabu  K. Srinivas  Bindu Sulochanan 《Journal of Oceanography》2014,70(3):251-266

Coastal marine environments are important links between the continents and the open ocean. The coast off Mangalore forms part of the upwelling zone along the southeastern Arabian Sea. The temperature, salinity, density, dissolved oxygen and stable oxygen isotope ratio (δ¹⁸O) of surface waters as well as those of bottom waters off coastal Mangalore were studied every month from October 2010 to May 2011. The coastal waters were stratified in October and November due to precipitation and runoff. The region was characterised by upwelled bottom waters in October, whereas the region exhibited a temperature inversion in November. The surface and bottom waters presented almost uniform properties from December until April. The coastal waters were observed to be most dense in January and May. Comparatively cold and poorly oxygenated bottom waters during the May sampling indicated the onset of upwelling along the region. δ¹⁸O of the coastal waters successfully documented the observed variations in the hydrographical characteristics of the Mangalore coast during the monthly sampling period. We also noted that the monthly variability in the properties of the coastal waters of Mangalore was related to the hydrographical characteristics of the adjacent open ocean inferred from satellite-derived surface winds, sea surface height anomaly data and sea surface temperatures.  相似文献   

Solitary sound pulses via electron-vortex distribution in partially ionized plasmas     

J. Srinivas  P. K. Shukla 《Astrophysics and Space Science》1994,219(1):143-147

It is shown that nonlinear propagation of sound waves in partially ionized collisional plasmas is governed by a modified Korteweg-de Vries (mKdV) equation when the electron distribution function deviates from the Boltzmann distribution. The mKdV equation admits a sharply localized solitary sound pulse, the profile and width of which are different from that which involves the Boltzmann electron number density response. Since the electron-vortex distribution induced solitary sound pulses are more pronounced, it can easily be identified in partially ionized plasmas.  相似文献   

Downscaling of precipitation for climate change scenarios: A support vector machine approach   总被引：7，自引：0，他引：7  

Shivam Tripathi  V.V. Srinivas  Ravi S. Nanjundiah 《Journal of Hydrology》2006,330(3-4):621-640

The Climate impact studies in hydrology often rely on climate change information at fine spatial resolution. However, general circulation models (GCMs), which are among the most advanced tools for estimating future climate change scenarios, operate on a coarse scale. Therefore the output from a GCM has to be downscaled to obtain the information relevant to hydrologic studies. In this paper, a support vector machine (SVM) approach is proposed for statistical downscaling of precipitation at monthly time scale. The effectiveness of this approach is illustrated through its application to meteorological sub-divisions (MSDs) in India. First, climate variables affecting spatio-temporal variation of precipitation at each MSD in India are identified. Following this, the data pertaining to the identified climate variables (predictors) at each MSD are classified using cluster analysis to form two groups, representing wet and dry seasons. For each MSD, SVM- based downscaling model (DM) is developed for season(s) with significant rainfall using principal components extracted from the predictors as input and the contemporaneous precipitation observed at the MSD as an output. The proposed DM is shown to be superior to conventional downscaling using multi-layer back-propagation artificial neural networks. Subsequently, the SVM-based DM is applied to future climate predictions from the second generation Coupled Global Climate Model (CGCM2) to obtain future projections of precipitation for the MSDs. The results are then analyzed to assess the impact of climate change on precipitation over India. It is shown that SVMs provide a promising alternative to conventional artificial neural networks for statistical downscaling, and are suitable for conducting climate impact studies.  相似文献   

Physical Modeling Results on Modified Pseudodepth Sections in Exploration of Highly Resistive Targets     

A. Apparao  G. S. Srinivas  V. Subrahmanya Sarma 《Pure and Applied Geophysics》1997,150(2):341-352

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Far infrared photometry of planets: Saturn and Venus: Volume 38, Number 3 (1979), in the article,by R. Courtin,P. Léna,M. De Muizon,D. Rouan,C. Nicollier,and J. Wijnbergen,pp. 411–419     

Srinivas N. Mohan 《Icarus》1979,40(2):317-330

The global distribution of existing lunar topography suffers from a lack of measurements of far-side radii because of the sparsity of data types in the nonequatorial regions. This paper presents determinations of far-side lunar radii based on the reduction of photogrammetric measurements derived from selected Apollo 16 trans-Earth phase photographs. The regions covered in this analysis lie west of Mare Moscoviense between longitudes 90 and 130°E and latitudes 10 and 60°N. The determinations are made using control points appearing on both NASA topographic orthophoto maps and the Apollo 16 photographs. The estimated lunar radii are referred to these control points and determined with a relative accuracy of 500 m. The new lunar radii are used to generate a topographic map covering the area investigated. The map shows that, with the given spatial density of surface festures measured, basin-sized features can be resolved. In particular, the far-side craters Fabry, Riemann, and Szilard comprise a topographically depressed region about 500 km in diameter centered at 120°E and 38.5°N. The floor of this basin is 2.4 to 3.4 km below the reference sphere of 1738.0 km and 4.8 to 5.8 km below the northern rim of the basin. A comparison of the depth of the unfilled basin with the depths of maria-filled front-side basins leads to the conclusion that basalt fill of the near-side maria may be 2 km deep. The topographic map shows good correlation with geologic provinces of young plains and cratered terra in the far-side highland region investigated. Lack of correlation between sampled values of the state-of-the-art 16th-order and 16th-degree harmonic gravity field model and corresponding topographical values leads to the conclusion that the far-side region investigated is isostatically compensated.  相似文献   

Analysis of multi-channel seismic refection and magnetic data along 13° N latitude across the bay of bengal     

D. Gopala Rao  G. C. Bhattacharya  M. V. Ramana  V. Subrahmanyam  T. Ramprasad  K. S. Krishna  A. K. Chaubey  G. P. S. Murty  K. Srinivas  Maria Desa  S. I. Reddy  B. Ashalata  C. Subrahmanyam  G. S. Mital  R. K. Drolia  S. N. Rai  S. K. Ghosh  R. N. Singh  R. Majumdar 《Marine Geophysical Researches》1995,17(3):321-322

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Carbonaceous aerosols over Pune and Hyderabad (India) and influence of meteorological factors     

Kaushar Ali  A. S. Panicker  G. Beig  R. Srinivas  P. Acharja 《Journal of Atmospheric Chemistry》2016,73(1):1-27

Sampling of particulate matter with aerodynamic diameter cut off at 2.5 μm (PM_2.5) has been carried out over a semi urban site of Pune and an urban site of Hyderabad. Analysis of elemental Carbon (EC) and Organic Carbon (OC) present in PM_2.5 was carried out using advanced Desert Research Institute’s (DRI) Thermal/Optical Carbon Analyzer operated on IMPROVE_ A (Interagency Monitoring of Protected Visual Environments_ A) protocol. It is found that average concentration of EC and OC both at Pune and Hyderabad was highest during winter season and lowest during monsoon season. Winter high is mainly controlled by inversion, whereas monsoon low is due to rain-out and wash-out process. OC/EC ratio showed higher variation over Pune compared to that over Hyderabad in different seasons, indicating divergent sources of emission of OC and EC at Pune. Formation of Secondary Organic Carbon (SOC) has also been identified as one of the reasons for wide variation in OC/EC ratio value in different seasons over both the sites.  相似文献   

OBSERVATIONS ON ESTUARINE FLUID MUD ENTRAINMENT     

Srinivas  R.  Mehta  A. J. Graduate Research Assistant. Coastal  Oceanographic Engineering Department  University of Florida. Gainesville. FL . U. S. A.  Professor  Coastal  Deeanographic Engineering Department. University of Florida. Gainesville. FL U. S. A. 《国际泥沙研究》1990,(1)

I. INTRODUCTIONPrediction of mud bed erosion by forcing due to tidal currents usually requires a numerical solution of the advection--dispersion equation for sediment mass transport. Key role is of course played inthis by the bottom boundary conditions defining erosion and deposition fluxes. The issue of erosion isbriefly considered here. noting that it is customary to calculate the rate of erosion as a function of thebed shear stress in excess of the erosion shear strength of the bed (Me…  相似文献   

Spherical harmonic synthesis and least squares computations in satellite gravity gradiometry     

Srinivas V. Bettadpur  Bob E. Schutz  John B. Lundberg 《Journal of Geodesy》1992,66(3):261-271

The computational requirements in the simulations of geopotential estimation from satellite gravity gradiometry are discussed. Fast algorithms for spherical harmonic synthesis and least squares accumulation on a vectorizing supercomputers are presented. Using these methods, in a test case estimation of 2595 coefficients of a degree and order 50 gravity field, sustained program execution speeds of 275 Mflops (87 % peak machine speed) on a single processor of a CRAY Y-MP were achieved, with spherical harmonics computation accounting for less than 1 % of total cost. From the results, it appears that brute-force estimation of a degree and order 180 field would require 537 Million Words of memory and 85 hours of CPU time, assuming mission duration of 1 month, and execution speed of 1 Gflops. Both memory size and execution speed requirements are within the capabilities of modern multi-processor supercomputers.  相似文献   

A Study on the Influence of the Land Surface Processes on the Southwest Monsoon Simulations using a Regional Climate Model     

C. V. Srinivas  D. V. Bhaskar Rao  D. Hari Prasad  K. B. R. R. Hari Prasad  R. Baskaran  B. Venkatraman 《Pure and Applied Geophysics》2015,172(10):2791-2811

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