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51.
K. R. Manjunath Shibendu Shankar Ray Sushma Panigrahy 《Journal of the Indian Society of Remote Sensing》2011,39(4):599-602
Hyperspectral remote sensing, because of its large number of narrow bands, has shown possibility of discriminating the crops.
Current study was carried out to select the optimum bands for discrimination among pulses, cole crops and ornamental plants
using the ground-based Hyperspectral data in Patha village, Lalitpur district, Uttar Pradesh state and Kolkata, West Bengal
state. The field observations of reflectance were taken using a 512-channel spectroradiometer with a range of 325–1075 nm.
The stepwise discriminant analysis was carried out and separability measures, such as Wilks’ lambda and F-Value were used as criteria for identifying the narrow bands. The analysis showed that, the best four bands for pulse crop
discrimination lie mostly in NIR and early MIR regions i.e. 750, 800, 940 and 960 nm. Within cole crops discrimination is
primarily determined by the green, red and NIR bands of 550, 690, 740, 770 and 980 nm. The separability study showed the bands
420,470,480,570,730,740, 940, 950, 970, 1030 nm are useful for discriminating flowers. 相似文献
52.
Sushma Panigrahy Shibendu Shankar Ray K. R. Manjunath P. S. Pandey S. K. Sharma Anil Sood Manoj Yadav P. C. Gupta N. Kundu Jai Singh Parihar 《Journal of the Indian Society of Remote Sensing》2011,39(3):355-364
Cropping system study is not only useful to understand the overall sustainability of agricultural system, but also it helps
in generating many important parameters which are useful in climate change impact assessment. Considering its importance,
Space Applications Centre, took up a project for mapping and characterizing major cropping systems of Indo-Gangetic Plains
of India. The study area included the five states of Indo-Gangetic Plains (IGP) of India, i.e. Punjab, Haryana, Uttar Pradesh,
Bihar and West Bengal. There were two aspects of the study. The first aspect included state and district level cropping system
mapping using multi-date remote sensing (IRS-AWiFS and Radarsat ScanSAR) data. The second part was to characterize the cropping
system using moderate spatial resolution multi-date remote sensing data (SPOT VGT NDVI) and ground survey. The remote sensing
data was used to compute three cropping system performance indices (Multiple Cropping Index, Area Diversity Index and Cultivated
Land Utilization Index). Ground survey was conducted using questionnaires filled up by 1,000 farmers selected from 103 villages
based on the cropping systems map. Apart from ground survey, soil and water sampling and quality analysis were carried out
to understand the effect of different cropping systems and their management practices. The results showed that, rice-wheat
was the major cropping system of the IGP, followed by Rice-Fallow-Fallow and Maize-Wheat. Other major cropping systems of
IGP included Sugarcane based, Pearl millet-Wheat, Rice-Fallow-Rice, Cotton-Wheat. The ground survey could identify 77 cropping
systems, out of which 38 are rice-based systems. Out of these 77 cropping systems, there were 5 single crop systems, occupying
6.5% coverage (of all cropping system area), 56 double crop systems with 72.7% coverage, and 16 triple crop systems with 20.8%
coverage. The cropping system performance analysis showed that the crop diversity was found to be highest in Haryana, while
the cropping intensity was highest in Punjab state. 相似文献
53.
The stable carbon isotopic compositions of light hydrocarbon gases adsorbed in near-surface soil and sediments from the Saurashtra basin were characterized for their origin and maturity. Saurashtra is considered geologically prospective for oil and gas reserves; however, a major part of the basin is covered by the Deccan Traps, hindering the exploration of Mesozoic hydrocarbon targets. Surface geochemical prospecting, based on micro-seepage of hydrocarbons from subsurface accumulations, could be advantageous in such areas. In light of this, 150 soil samples were collected from the northwestern part of Saurashtra, around the Jamnagar area, where a thick sedimentary sequence of about 2–3 km exists under 1–1.5 km of Deccan basalt. The concentration of acid desorbed alkane gases from soil samples was found to vary (in ppb) as: methane (C1) = 3–518; ethane (C2) = 0–430; propane (C3) = 0–331; i-butane (iC4) = 0–297; n-butane (nC4) = 2–116; i-pentane (iC5) = 0–31 and n-pentane (nC5) = 0–23, respectively.Fifteen samples with high concentrations of alkane gases were measured for their δ13C1; δ13C2 and δ13C3 compositions using gas chromatography–combustion-isotope ratio mass spectrometry (GC–C-IRMS). The values for methane varied from ? 27 to ? 45.4‰, ethane from ? 20.9 to ? 27.6‰, and propane from ? 20.4 to ? 29.1‰ versus the Vienna PeeDee Belemnite (VPDB). The carbon isotope ratio distribution pattern represents isotopic characteristics pertaining to hydrocarbon gases derived from thermogenic sources. Comparisons of carbon isotopic signatures and compositional variations with the standard carbon isotopic models suggest that hydrocarbon gases found in the shallow depths of the study area are not of bacterial origin but are formed thermally from deeply buried organic matter, likely to be mainly a terrestrial source rock with a partial contribution from a marine source. These gases may have migrated to the near-surface environment, where they represent an admixture of thermally generated hydrocarbon gases from mixed sources and maturity. The maturity scale (δ13C versus Log Ro %) applied to the surface sediment samples of the Jamnagar area indicated the source material to be capable of generating oil and gas. The detection of thermogenic alkane gases in near-surface sediments offers the possibility of hydrocarbons at depth in Saurashtra. 相似文献
54.
Trapped waves of the 27 November 1945 Makran tsunami: observations and numerical modeling 总被引:1,自引:1,他引:0
S. Neetu I. Suresh R. Shankar B. Nagarajan R. Sharma S. S. C. Shenoi A. S. Unnikrishnan D. Sundar 《Natural Hazards》2011,59(3):1609-1618
The 27 November 1945 earthquake in the Makran Subduction Zone triggered a destructive tsunami that has left important problems
unresolved. According to the available reports, high waves persisted along the Makran coast and at Karachi for several hours
after the arrival of the first wave. Long-duration sea-level oscillations were also reported from Port Victoria, Seychelles.
On the other hand, only one high wave was reported from Mumbai. Tide-gauge records of the tsunami from Karachi and Mumbai
confirm these reports. While the data from Mumbai shows a single high wave, Karachi data shows that high waves persisted for
more than 7 h, with maximum wave height occurring 2.8 h after the arrival of the first wave. In this paper, we analyze the
cause of these persistent high waves using a numerical model. The simulation reproduces the observed features reasonably well,
particularly the persistent high waves at Karachi and the single high wave at Mumbai. It further reveals that the persistent
high waves along the Makran coast and at Karachi were the result of trapping of the tsunami-wave energy on the continental
shelf off the Makran coast and that these coastally-trapped edge waves were trapped in the along-shore direction within a
∼300-km stretch of the continental shelf. Sensitivity experiments establish that this along-shore trapping of the tsunami
energy is due to variations in the shelf width. In addition, the model simulation indicates that the reported long duration
of sea-level oscillations at Port Victoria were mainly due to trapping of the tsunami energy over the large shallow region
surrounding the Seychelles archipelago. 相似文献
55.
Devleena Mani T. Satish Kumar M. A. Rasheed D. J. Patil A. M. Dayal T. Gnaneshwar Rao V. Balaram 《Natural Resources Research》2011,20(1):75-88
The association of iodine with organic matter in sedimentary basins is well documented. High iodine concentration in soils
overlying oil and gas fields and areas with hydrocarbon microseepage has been observed and used as a geochemical exploratory
tool for hydrocarbons in a few studies. In this study, we measure iodine concentration in soil samples collected from parts
of Deccan Syneclise in the west central India to investigate its potential application as a geochemical indicator for hydrocarbons.
The Deccan Syneclise consists of rifted depositional sites with Gondwana–Mesozoic sediments up to 3.5 km concealed under the
Deccan Traps and is considered prospective for hydrocarbons. The concentration of iodine in soil samples is determined using
ICP-MS and the values range between 1.1 and 19.3 ppm. High iodine values are characteristic of the northern part of the sampled
region. The total organic carbon (TOC) content of the soil samples range between 0.1 and 1.3%. The TOC correlates poorly with
the soil iodine (r
2 < 1), indicating a lack of association of iodine with the surficial organic matter and the possibility of interaction between
the seeping hydrocarbons and soil iodine. Further, the distribution pattern of iodine compares well with two surface geochemical
indicators: the adsorbed light gaseous hydrocarbons (methane through butane) and the propane-oxidizing bacterial populations
in the soil. The integration of geochemical observations show the occurrence of elevated values in the northern part of the
study area, which is also coincident with the presence of exposed dyke swarms that probably serve as conduits for hydrocarbon
microseepage. The corroboration of iodine with existing geological, geophysical, and geochemical data suggests its efficacy
as one of the potential tool in surface geochemical exploration of hydrocarbons. Our study supports Deccan Syneclise to be
promising in terms of its hydrocarbon prospects. 相似文献
56.
P. Lakshmi Srinivasa Rao D. Srinu M. A. Rasheedd M. S. Kalpana D. J. Patil A. M. Dayal 《Journal of the Geological Society of India》2013,82(6):666-674
Direct correlation have been observed between certain trace element and hydrocarbon anomalies in the near subsurface soils of Vindhyan basin, India. This relationship with hydrocarbon is very useful in hydrocarbon exploration. 52 soil samples from Vindhyan basin were collected from a depth of 2.5m. All the soil samples were analyzed for light hydrocarbon, isotope and trace element concentrations. The adsorbed light gaseous hydrocarbon analyses show the presence of methane (8–328 ppb), ethane (0–27 ppb) and propane (0–11 ppb) respectively and these values indicate the presence of hydrocarbon micro-seepage in the study area. The carbon isotopic values determined for methane and ethane for these soil samples are (?26.41 to ?47.70 ‰ PDB) and (?20.07 to ?35.30 ‰ PDB) respectively and they are thermogenic in nature. The trace element concentrations of nickel (33–220 ppm), vanadium (72–226 ppm), copper (20–131 ppm), chromium (94–205 ppm), zinc (66–561 ppm) and cobalt (9–39 ppm) have higher than the normal concentrations in soils. Trace element concentrations are used to plot with the data obtained from light gaseous hydrocarbon concentrations and carbon isotopic values of soil samples of the Vindhyan basin. Trace element anomalies have been observed around the hydrocarbon anomalies in the study area. 相似文献
57.
Knowledge of dielectric permittivity of the soil provides direct measure of soil moisture content. A methodology to determine soil moisture based on the reflection coefficient measurement by a pseudo vector method using a horn antenna has been presented. To verify the efficacy of the method, measurements have been carried out at S, C & X band frequencies at two moisture levels and the corresponding emissivity parameters computed. Results so obtained are in good agreement with the already reported data and the direct moisture measurements. This method is expected to be of interest to agricultural scientists and to those involved in the application of remote sensing in crop studies. 相似文献
58.
E. Dayal 《GeoJournal》1990,20(3):293-299
59.
Srikanta Murthy S. Mahesh Jyoti Shankar Roy 《Journal of the Geological Society of India》2016,88(5):549-558
Palynological and petrological studies have been undertaken on the Gondwana coal and associated lithologies encountered in borehole EBM-2 of East Bokaro coalfield of Damodar Basin, India. The palynological investigation resulted in the recognition of Assemblage–III (Densipollenites, 27.9 m–214.30 m), Assemblage–II (Striatopodocarpites + Faunipollenites, 225.00 m–297.60 m) and Assemblage–I (Faunipollenites + Scheuringipollenites, 307.00m–433.00 m). Lithofacies study was also done for better understanding of the preservation and abundance/paucity of the spores and pollen in different lithologies as the current borehole has significant thickness of mudstones, shales and siltstone. Palynofacies study and Petrographical studies of coal samples encountered in the borehole were used to determine the depositional environment of the coal precursor peat swamp. Palynological data has revealed the presence of younger Raniganj palynoflora between 27.00-214.30 m depth that is lithologically defined as Barren Measures Formation. This spore pollen study has proved that these sediments were deposited during late early Permian to late Permian period. Further the maceral analysis of organic sediments as well as the Thermal Alteration Index (TAI) has revealed that the coaly shale at 336.5 m depth has hydrocarbon generation potential. 相似文献
60.
A three-dimensional finite-difference multilevel hydrodynamic model is developed using an explicit scheme on a staggered grid. The model has been tested against four cases, namely (i) wind-induced circulation (ii) density-driven circulation (iii) seiche oscillation in a closed basin and (iv) tide-induced circulation in a open channel. The results obtained in the present study compare well with those obtained from the corresponding analytical solutions under idealised conditions for the above four cases. The model was also tested against the case of circulation induced by wind and Coriolis force and the results obtained are compared with the results of Davies and Owen (1979). 相似文献