Automated Approach for Extraction of Oil Spill from SAR Imagery     

Sauvic Dutta  Manoj Joseph  Emani Venkata Suriya Sita Kumari  Andugulapati Veera Venkateswara Prasad 《Journal of the Indian Society of Remote Sensing》2018,46(4):633-639

Oil spill pollution is a major environmental concern since it has most dangerous and hazardous effects on marine environment. Periodic monitoring by detecting oil spills along with its movement, helps in efficient clean-up and recovery operations. Over the past few years, Synthetic Aperture Radar (SAR) based remote sensing has received considerable attention for monitoring and detecting oil spill due to its unique capabilities to provide wide-area observation in all weather conditions. However, the interpretation of marine SAR imagery is often ambiguous, since it is difficult to separate oil spill from look-alike features. The objective behind our study was to extract probable oil spill candidates automatically from SAR imageries containing oil spill incidences, where new methods based on over-segmentation and amalgamate approach is used for this purpose. The methodology is all about over segmenting the entire image based on its statistics and amalgamating relevant segments at later point of time to represent actual dark features as probable oil spill candidates. Under the dependency on SAR imageries alone, the approach does not take care of the separation of look-alike features which can be addressed subsequently by the consideration of associated synchronous external data resources such as optical data, wind and ocean parameters (Zhao et al. in Opt Express 22(11):13755–13772, 2014; Espedal and Wahl in Int J Remote Sens 20(1):49–65, 1999). The approach is carried out on a set of RISAT-1 imagery containing oil spill incidences and the extracted oil spill areas are in well agreement with the visually interpreted output with kappa coefficient greater than 0.70 and overall classification accuracy greater than 80%.  相似文献   

Principal component analysis for interaction of nitrifiers and wastewater environments at a full-scale activated sludge plant     

O. O. Awolusi  M. Nasr  S. Kumari  F. Bux 《International Journal of Environmental Science and Technology》2018,15(7):1477-1490

This study investigated the relationship between wastewater environments and the nitrifiers at a full-scale plant using principal component analysis. Ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were detected by florescent in situ hybridization, polymerase chain reaction, phylogenetic analysis, real-time quantitative polymerase chain reaction. Pyrosequencing was also used in profiling the ammonia monooxygenase locus of ammonia-oxidizing bacteria community. It was found that the dominant ammonia-oxidizing bacteria sequences were related to uncultured ammonia-oxidizing bacterium, uncultured Nitrosomonadaceae bacterium, Nitrosomonas sp., and uncultured bacterium. In addition, Nitrobacter clones were related to uncultured alpha proteobacterium, uncultured bacterium, uncultured Nitrobacter sp., and uncultured Bradyrhizobium sp., whereas Nitrospira clones were similar to uncultured bacterium, Candidatus Nitrospira defluvii, uncultured Nitrospira sp., and uncultured Nitrospirae bacterium. The ammonia-oxidizing bacteria and nitrite-oxidizing bacteria ranged 2.83 × 10⁸–1.33 × 10¹⁰ and 1.25 × 10¹⁰–1.13 × 10¹¹ copies L^?1, respectively, equivalent to nitrite-oxidizing bacteria: ammonia-oxidizing bacteria ratio of 10:1. The first three parts of the principal components analysis accounted for 76.8% of the explained variance. The first principal component (44.4%) designated that ammonia-oxidizing bacteria and Nitrospira were mainly influenced by seasonal variations, followed by chemical oxygen demand concentration and nitrogen species (i.e., ammonia, nitrite, and nitrate). The second principal component (19.1%) showed no information about the nitrifiers’ interaction with environmental factors, whereas Nitrobacter demonstrated a high correlation with ammonia on the third principal component (13.3%). These results revealed that the species of Nitrobacter were less influenced by environmental conditions than ammonia-oxidizing bacteria and Nitrospira spp.  相似文献   

Chemometric analysis to infer hydro-geochemical processes in a semi-arid region of India   总被引：1，自引：0，他引：1  

Chander Kumar Singh  Satyanarayan Shashtri  Kumari Rina  Saumitra Mukherjee 《Arabian Journal of Geosciences》2013,6(8):2915-2932

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   

Agricultural drought assessment at disaggregated level using AWiFS/WiFS data of Indian Remote Sensing satellites     

C. S. Murthy  M. V. R. Sesha Sai  V. Bhanuja Kumari  P. S. Roy 《国际地球制图》2013,28(2):127-140

Spatial differences in drought proneness and intensity of drought caused by differences in cropping patterns and crop growing environments within a district indicate the need for agricultural drought assessment at disaggregated level. The objective of this study is to use moderate resolution satellite images for detailed assessment of the agricultural drought situation at different administrative units (blocks) within a district. Monthly time composite NDVI images derived from moderate resolution AWiFS (60 m) and WiFS (180 m) images from Indian Remote Sensing satellites were analysed along with ground data on rainfall and crop sown areas for the kharif seasons (June – November) of 2002 (drought year), 2004 (early season drought) and 2005 (good monsoon year). The impact of the 2002 meteorological drought on crop area in different blocks of the district was assessed. The amplitude of crop condition variability in a severe drought year (2002) and a good year (2005) was used to map the degree of vulnerability of different blocks in the district to agricultural drought. The impact of early season deficit rainfall in 2004 on the agricultural situation and subsequent recovery of the agricultural situation was clearly shown. Agricultural drought assessment at disaggregated level using moderate resolution images is useful for prioritizing the problem areas within a district to undertake, in season drought management plans, such as alternate cropping strategies, as well as for end of the season drought relief management actions. The availability of ground data on rainfall, cropping pattern, crop calendar, irrigation, soil type etc., is very crucial in order to interpret the seasonal NDVI patterns at disaggregated level for drought assessment. The SWIR band of AWiFS sensor is a potential data source for assessing surface drought at the beginning of the season.  相似文献   

Near-field and far-field simulation of accelerograms of Sikkim earthquake of September 18, 2011 using modified semi-empirical approach     

A. Joshi  Pushpa Kumari  Sandeep Singh  M. L. Sharma 《Natural Hazards》2012,64(2):1029-1054

The semi-empirical approach for modeling of strong ground motion given by Midorikawa (Tectonophysics 218:287?C295, 1993) has been modified in the present paper for component wise simulation of strong ground motion. The modified approach uses seismic moment in place of attenuation relation for scaling of acceleration envelope. Various strong motion properties like directivity effect and dependence of peak ground acceleration with respect to surface projection of source model have been studied in detail in the present work. Recently, Sikkim earthquake of magnitude 6.9 (M _w ) that occurred on September 18, 2011 has been recorded at various near-field and far-field strong motion stations. The modified semi-empirical technique has been used to confirm the location and parameters of rupture responsible for this earthquake. Strong motion record obtained from the iterative modeling of the rupture plane has been compared with available strong motion records from near as well as far-field stations in terms of root mean square error between observed and simulated records. Several possibilities of nucleation point, rupture velocity, and dip of rupture plane have been considered in the present work and records have been simulated at near-field stations. Final selection of model parameters is based on root mean square error of waveform comparison. Final model confirms southward propagating rupture. Simulations at three near-field and twelve far-field stations have been made using final model. Comparison of simulated and observed record has been made in terms of peak ground acceleration and response spectra at 5?% damping. Comparison of simulated and observed record suggests that the method is capable of simulating record which bears realistic appearance in terms of shape and strong motion parameters. Present work shows that this technique gives records which matches in a wide frequency range for Sikkim earthquake and that too from simple and easily accessible parameters of the rupture plane.  相似文献   

Bianchi type-V anisotropic cosmological models in certain theories of gravitation with perfect fluid distribution     

V. U. M. Rao  T. Vinutha  M. Vijaya Shanthi  G. Sree Devi Kumari 《Astrophysics and Space Science》2008,317(1-2):89-94

Exact Bianchi type-V cosmological models are presented in Einstein’s theory of gravitation with cosmological constant Λ in case of perfect fluid distribution. Also obtained Bianchi type-V cosmological models in a scalar-tensor theory of gravitation proposed by Saez and Ballester (1986) in case of perfect fluid distribution using and without using negative constant deceleration parameter. Some physical and geometrical properties of the models are also discussed.  相似文献   

Tannery Effluents: Current Practices,Environmental Consequences,Human Health Risks,and Treatment Options     

Kavita Singh  Madhu Kumari  Kumar Suranjit Prasad 《洁净——土壤、空气、水》2023,51(3):2200303

The tannery industry influences the gross domestic product/economic activity of any country, but the uncontrolled release of tannery effluents causes environmental degradation and increases health risks to human. The reason for the toxicity of tannery effluents is the presence of high concentrations of organic and inorganic chemicals used in the production of leather goods. Untreated or partially treated effluents discharged into surface water results in an increase in both chemical and biological oxygen demand as well as in an increase in the levels of total suspended solids, dissolved solids, and toxic metals in environmental bodies, especially in soil, water bodies, and water sediments. Various treatment techniques, such as physicochemical, biological, and advanced oxidation methods, which include chemical precipitation, electrocoagulation, aerobic or anaerobic treatment, wetland construction, and Fenton, electro-Fenton, and photo-Fenton processes are also described. This review also discusses the technical appropriateness and economic feasibility of reducing the effluent pollution load and solid waste emanating from the tannery industry. Considering the enhanced health risks in the tannery waste treatment and management regime, some green and advanced technologies should be explored. A sustainable green technology that avoids the use of toxic chemicals in the tanning process is seen well for ecological health.  相似文献   

DEM-based delineation for improving geostatistical interpolation of rainfall in mountainous region of Central Himalayas,India     

Madhuri?Kumari  Chander?Kumar?SinghEmail author  Oinam?Bakimchandra  Ashoke?Basistha 《Theoretical and Applied Climatology》2017,130(1-2):51-58

In mountainous region with heterogeneous topography, the geostatistical modeling of the rainfall using global data set may not confirm to the intrinsic hypothesis of stationarity. This study was focused on improving the precision of the interpolated rainfall maps by spatial stratification in complex terrain. Predictions of the normal annual rainfall data were carried out by ordinary kriging, universal kriging, and co-kriging, using 80-point observations in the Indian Himalayas extending over an area of 53,484 km². A two-step spatial clustering approach is proposed. In the first step, the study area was delineated into two regions namely lowland and upland based on the elevation derived from the digital elevation model. The delineation was based on the natural break classification method. In the next step, the rainfall data was clustered into two groups based on its spatial location in lowland or upland. The terrain ruggedness index (TRI) was incorporated as a co-variable in co-kriging interpolation algorithm. The precision of the kriged and co-kriged maps was assessed by two accuracy measures, root mean square error and Chatfield’s percent better. It was observed that the stratification of rainfall data resulted in 5–20 % of increase in the performance efficiency of interpolation methods. Co-kriging outperformed the kriging models at annual and seasonal scale. The result illustrates that the stratification of the study area improves the stationarity characteristic of the point data, thus enhancing the precision of the interpolated rainfall maps derived using geostatistical methods.  相似文献   

Estimation of model parameter of Sumatra earthquake using empirical Green’s function technique and generation of hypothetical earthquake scenario for Andaman Island, India     

A. Joshi  Pushpa Kumari  Sushil Kumar  M. L. Sharma  A. K. Ghosh  M. K. Agarwal  A. Ravikiran 《Natural Hazards》2012,62(3):1081-1108

Empirical Green??s function (EGF) technique is considered to be most effective technique for simulation of ground motions due to a finite earthquake source. In the present paper, this technique has been used to simulate ground motion due to a great earthquake. The coastal region of Sumatra Island has been visited by a great earthquake on December 26, 2004. This earthquake has been recorded at several broadband stations including a nearest broadband station PSI in Indonesia. The shear wave contributions in both horizontal components have been simulated at PSI station using EGF technique. The comparison of simulated and observed waveform has been made for various possibilities of rupture parameters in terms of root mean square error. The final rupture model supports rupture velocity of 3.0?km/s with nucleation point supporting northward propagating rupture that coincide with high-slip asperity defined by Sorensen et al. (Bull Seism Soc Am 97:S139?CS151, 2007). The final modeling parameters have been used to simulate record at MDRS station in coastal state of Tamilnadu, India. In an attempt to model a scenario of great earthquake in the Andaman Island, a hypothetical rupture plane is modeled in this region. The event occurred on August 10, 2008 of magnitude 6.2 (M _w ) recorded on strong motion array at Port Blair has been used as EGF to simulate records due to the hypothetical great earthquake. Possibilities of earthquake due to the oblique strike-slip and thrust mechanism have been modeled in the present paper. Several possibilities of nucleation point for both cases has been considered, and it is seen that variation of peak ground acceleration at Port Blair station for strike-slip and thrust mechanism is 126?C738 gals and 647?C2,571 gals, respectively, which indicate high seismic hazard potential of Andaman Island.  相似文献   

Modeling of strong motion generation area of the Uttarkashi earthquake using modified semiempirical approach     

Sandeep  A. Joshi  Kamal  Parveen Kumar  Pushpa Kumari 《Natural Hazards》2014,73(3):2041-2066

The semiempirical approach based on envelope summation method given by Midorikawa (Tectonophysics 218:287–295, 1993) has been modified in this paper for modeling of strong motion generation areas (SMGAs). Horizontal components of strong ground motion have been simulated using modifications in the semiempirical approach given by Joshi et al. (Nat Hazard 71:587–609, 2014). Various modifications in the technique account for finite rupture source, layering of earth, componentwise division of energy and frequency-dependent radiation pattern. In this paper, SMGAs of the Uttarkashi earthquake have been modeled. Two different isolated wave packets in the recorded accelerogram have been identified from recorded ground motion, which accounts for two different SMGAs in the entire rupture plane. The approximate locations of SMGAs within the rupture plane were estimated using spatio-temporal variation of 77 aftershocks. Source parameters of each SMGA were calculated from theoretical and observed source displacement spectra computed from two different wave packets in the record. The final model of rupture plane responsible for the Uttarkashi earthquake consists of two SMGAs, and the same has been used to simulate horizontal components of acceleration records at different station using modified semiempirical technique. Comparison of the observed and simulated acceleration records in terms of root mean square error confirms the suitability of the final source model for the Uttarkashi earthquake.  相似文献