Estimating fractal dimension of lineaments using box counting method for the Indian landmass     

V. Jaya  S. Sonika Mohan 《国际地球制图》2013,28(3):314-331

A fractal in general is a scale-invariant object that has an underlying power-law equation and is characterized by a positive fractal dimension. The fractal dimension of the Indian landmass is evaluated from the lineament map by utilizing the MATLAB programme for box counting method. The lineament map of India is divided into grids. The fractal dimension of each grid is obtained and the values are mapped. Most of the regions of India has fractal dimension in the range 1–1.25. The fractal values are compared with b-value in Gutenberg–Richter equation which gives a relationship between frequency of occurrence of earthquake and its magnitude. The estimation of b-value requires a complete earthquake dataset. In regions where the complete earthquake data are not available, the fractal dimension evaluated from the study can be used as a parameter to assess the seismic hazard of the region.  相似文献   

On the validity of series expansion being used for the position of a point on a Roche equipotential     

A. K. Lal  S. Saini  C. Mohan  V. P. Singh 《Astrophysics and Space Science》2007,310(3-4):317-320

The concept of Roche equipotentials has been frequently used in literature to study the problems of rotating stars and stars in binary systems. However in spite of using this simplifying concept, it is still not possible to express the position of a point in the potential field of such a system in a closed analytic form. In order to carry out further analytic studies, Kopal (Adv. Astron. Astrophys. 9:1–65, 1972), therefore, developed a series expansion for it. The series expansion of Kopal has often been used in the analysis of the problem of equilibrium structure and the periods of oscillations of rotating stars and stars in binary systems, but its validity and convergence has not been analytically established. It is important that this aspect of the problem is checked so that one is sure of the correctness of subsequent analysis and results based on this series expansion. In the present brief note, we have addressed ourselves to this problem and validated the correctness of the numerical results obtained through the use of this series expansion.  相似文献   

Generation and Validation of two Day Composite Wind Fields from Oceansat-2 Scatterometer     

Tata V. S. Udaya Bhaskar  Chiranjivi Jayaram  Saurabh Bansal  K Krishna Mohan  Debadatta Swain 《Journal of the Indian Society of Remote Sensing》2017,45(1):113-122

The Oceansat-2 scatterometer (OSCAT) of the Indian Space Research Organization (ISRO), provides surface wind speed and direction with a spatial resolution of 50 km × 50 km. With a revisit time of 2 days it had provided ocean surface wind vectors over the global oceans. In the present work, an attempt has been made to generate two day composite of OSCAT wind vectors using Data-Interpolating Variational Analysis (DIVA) and compare them with daily composite winds to check how better is the two day composites in comparison to daily composites. The daily and two days composite wind vectors of zonal (U) and meridional (V) components have been validated with wind measurements from in situ buoys and Advanced Scatterometer (ASCAT) for the year 2012 over the tropical Indian Ocean region. The statistical comparison with the in situ measurements and ASCAT has shown that the two-day OSCAT wind composites are slightly better than the daily composite winds. The improvement in the statistics can be attributed to the use of ascending and descending passes pertaining to two days which results in fewer gaps between passes, thereby reducing the interpolation errors.  相似文献   

Modified Dual Winner Takes All Approach for Tri-Stereo Image Matching Using Disparity Space Images     

Raghavendra Hemant Bhalerao  Shirish S. Gedam  Krishna Mohan Buddhiraju 《Journal of the Indian Society of Remote Sensing》2017,45(1):45-54

In this research paper, a new framework is proposed to increase the total number of correct matches for stereo correspondence using tri-stereo images. The research work investigates some of the less explored properties of Disparity Space Image (DSI), and considers the local maxima in addition to the global maximum of the cost function and propose a new tri-stereo matching method as Modified Dual Winner Takes All (MDWTA) using edges of disparity space image. Conventionally using a single DSI from a stereo pair optimization techniques are applied to get the disparity, whereas the proposed approach uses Winner Takes All (WTA) approach using two DSIs from a triplet. The dual property of DSI that is the manner in which it stores cost for rows and columns for forward and reverse matching is introduced. This property is applied to check consistency for forward and reverse matching in a single pass, which gives initial correct matches. Next a left-centre-right consistency check is applied to discard inconsistent disparities obtained from these three views. Subsequently to obtain disparity for gaps thus generated a rule is formulated using local maxima, edges and adjacent global maximum to find correct disparity. Evaluation of the results obtained is carried by comparing them with block matching WTA method and other recent methods such as, Dynamic Programming (DP) and Semi-Global Matching (SGM) applied on images from Terrain Mapping Camera of Chandrayaan-1 and PRISM sensor of the ALOS mission. Methodology proposed is also verified using standard Middlebury stereo dataset. Experimental results show that the proposed method gives an increased number of correct matches by 10–15 % as compared to basic WTA and DP. However the results obtained are better to SGM for certain regions and features.  相似文献   

Synergizing community-based forest monitoring with remote sensing: a path to an effective REDD+ MRV system     

M. S. R. Murthy  Hammad Gilani  Bhaskar Singh Karky  Eklabya Sharma  Marieke Sandker  Upama Ashish Koju  Shiva Khanal  Mohan Poudel 《Carbon balance and management》2017,12(1):19

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Enrichment of trace metals in surface sediments from the northern part of Point Calimere, SE coast of India   总被引：1，自引：0，他引：1  

V. Stephen-Pichaimani  M. P. Jonathan  S. Srinivasalu  N. Rajeshwara-Rao  S. P. Mohan 《Environmental Geology》2008,55(8):1811-1819

This study deals with the geochemical nature of distribution, enrichment of total trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) in bulk sediments and its association with sediment texture, carbonates and organic carbon. Sixty surface sediment samples were collected during two different seasons in 2002 and 2003 along the coastal regions in three transects from Nagapattinam town, north of Point Calimere in southeast coast of India. The sediments are mostly sandy silt and are dominated by the carbonate content. Organic carbon distribution indicates that they are brought in by the minor river input. Enrichment of trace metals is clearly identified by the domination of Pb, Zn, Cd with high values than the average crustal values and comparison of trace metals from other coastal regions in the southeast coast of India. Statistical analysis clearly indicates that Fe and Mn control the distribution of trace metals and are concentrated in the finer particles and organic carbon fraction. The increase in concentration signifies the need for regular monitoring of the offshore coastal region in southeast coast of India which was recently destroyed by the 2004 December tsunami event, and which is also located near the Sethu Samuthram Ship Canal Project.  相似文献   

Influence of circulation parameters on the AOD variations over the Bay of Bengal during ICARB     

Marina Aloysius  Mannil Mohan  S. Suresh Babu  Vijayakumar S. Nair  K. Parameswaran  K. Krishna Moorthy 《Journal of Earth System Science》2008,117(1):353-360

MODIS (Moderate Resolution Imaging Spectroradiometer) level-3 aerosol data, NCEP (National Centers for Environmental Prediction) reanalysis winds and QuikSCAT ocean surface winds were made use of to examine the role of atmospheric circulation in governing aerosol variations over the Bay of Bengal (BoB) during the first phase of the ICARB (Integrated Campaign for Aerosols, gases and Radiation Budget) campaign (March 18–April 12, 2006). An inter-comparison between MODIS level-3 aerosol optical depth (AOD) data and ship-borne MICROTOPS measurements showed good agreement with correlation 0.92 (p < 0.0001) and a mean MODIS underestimation by 0.01. During the study period, the AOD over BoB showed high values in the northern/north western regions, which reduced towards the central and southern BoB. The wind patterns in lower atmospheric layers (> 850 hPa) indicated that direct transport of aerosols from central India was inhibited by the presence of a high pressure and a divergence over BoB in the lower altitudes. On the other hand, in the upper atmospheric levels, winds from central and northern India stretched south eastwards and converged over BoB with a negative vorticity indicative of a downdraft. These wind patterns pointed to the possibility of aerosol transport from central India to BoB by upper level winds. This mechanism was further confirmed by the significant correlations that AOD variations over BoB showed with aerosol flux convergence and flux vorticity at upper atmospheric levels (600–500 hPa). AOD in central and southern BoB away from continental influences displayed an exponential dependence on the QuikSCAT measured ocean surface wind speed. This study shows that particles transported from central and northern India by upper atmospheric circulations as well as the marine aerosols generated by ocean surface winds contributed to the AOD over the BoB during the first phase of ICARB.  相似文献   

WRF model evaluation for the urban heat island assessment under varying land use/land cover and reference site conditions     

Shweta Bhati  Manju Mohan 《Theoretical and Applied Climatology》2016,124(1-2):385-399

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Value of Information in the Earth Sciences by Jo Eidsvik,Tapan Mukerji and Debarun Bhattacharjya     

Mohan Kelkar 《Mathematical Geosciences》2016,48(8):1013-1014

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A Tool Assessing Optimal Multi-Scale Image Segmentation     

A. Mohan Vamsee  P. Kamala  Tapas R. Martha  K. Vinod Kumar  G. Jai sankar  E. Amminedu 《Journal of the Indian Society of Remote Sensing》2018,46(1):31-41

Image segmentation to create representative objects by region growing image segmentation techniques such as multi resolution segmentation (MRS) is mostly done through interactive selection of scale parameters and is still a subject of great research interest in object-based image analysis. In this study, we developed an optimum scale parameter selector (OSPS) tool for objective determination of multiple optimal scales in an image by MRS using eCognition software. The ready to use OSPS tool consists of three modules and determines optimum scales in an image by combining intrasegment variance and intersegment spatial autocorrelation. The tool was tested using WorldView-2 and Resourcesat-2 LISS-IV Mx images having different spectral and spatial resolutions in two areas to find optimal objects for ground features such as water bodies, trees, buildings, road, agricultural fields and landslides. Quality of the objects created for these features using scale parameters obtained from the OSPS tool was evaluated quantitatively using segmentation goodness metrics. Results show that OSPS tool is able determine optimum scale parameters for creation of representative objects from high resolution satellite images by MRS method.  相似文献