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91.
Nita Bhagia G. D. Bairagi Sandeep Pandagre Gajendra Patel S. P. Vyas G. N. Naveen Kumar Indal Ramteke Pritam Mesharam 《Journal of the Indian Society of Remote Sensing》2017,45(2):285-295
A scheme called National Food Security Mission was launched by Government of India in 2007 for wheat, rice and pulses crops. At the request of Ministry of Agriculture for monitoring intensification of pulses a project called Pulses Intensification was taken up in Rabi season 2012–2013. Reliable statistics using advanced methods is very important for variety of pulse crops. Remotely sensed data can help in pre-harvest area estimation of pulse crops. Pulses in India are grown as partly scattered and partly contiguous crop. Growth in scattered areas and poor vegetation canopy of some of the pulse crops poses a challenge in its identification and discrimination using remotely sensed data. National Inventory of Rabi pulse crops in major growing regions of northern and southern parts of India was attempted. Multi-date AWiFS data and multi-date NDVI products of AWiFS of Rabi season 2014–2015 were used to study spectral-temporal behavior of pulse crops. Pulse crops accuracies of more than 95 % was observed in contiguous areas and 50–80.77 % in scattered regions. All India area estimate of Rabi pulses for the year 2014–2015 was 8963.327 ‘000 ha. 相似文献
92.
R K Nayak N Mishra V K Dadhwal N R Patel M Salim K H Rao C B S Dutt 《Journal of Earth System Science》2016,125(6):1189-1204
This study examines the consistency between the AVHRR and MODIS normalized difference vegetation index (NDVI) datasets in estimating net primary productivity (NPP) and net ecosystem productivity (NEP) over India during 2001–2006 in a terrestrial ecosystem model. Harmonic analysis is employed to estimate seasonal components of the time series. The stationary components (representing long-term mean) of the respective NDVI time series are highly coherent and exhibit inherent natural vegetation characteristics with high values over the forest, moderate over the cropland, and small over the grassland. Both data exhibit strong semi-annual oscillations over the cropland dominated Indo-Gangetic plains while annual oscillations are strong over most parts of the country. MODIS has larger annual amplitude than that of the AVHRR. The similar variability exists on the estimates of NPP and NEP across India. In an annual scale, MODIS-based NPP budget is 1.78 PgC, which is 27% higher than the AVHRR- based estimate. It revealed that the Indian terrestrial ecosystem remained the sink of atmospheric CO 2 during the study period with 42 TgC y ?1 NEP budget associated with MODIS-based estimate against 18 TgC y ?1 for the AVHRR-based estimate. 相似文献
93.
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95.
Elastic modulus and Poisson’s ratio of soils are two important parameters required for safe design of various civil engineering
structures. The elastic modulus and shear modulus of the soils are generally obtained from the resonant column, torsional
shear tests and geophysical methods. Though, from these parameters the Poisson’s ratio can be determined, these tests are
quite elaborate, cumbersome, time consuming and require skilled manpower particularly for data interpretation. Moreover, direct
determination of the Poisson’s ratio by employing micro-strain gauges, which measure axial and lateral strains using Wheatstone
bridge circuits, is difficult for soils due to the problems associated with their fixing on the surface of the sample. Under
these circumstances, application of piezoceramic elements, which can generate shear and compression waves, seems to be an
excellent alternative. Using these wave velocities, the Poisson’s ratio can be computed easily and precisely. However, how
this (computed) value of the Poisson’s ratio compares vis-à-vis that obtained from the conventional triaxial tests (i.e.,
strain controlled uniaxial compression tests), which yield stress–strain relationship, needs to be established. With this
in view, investigations were conducted on soils of different types (clays and sands) in their disturbed and undisturbed forms
by resorting to piezoceramic tests and the triaxial tests. Details of the methodology are presented in this paper and it has
been demonstrated that application of piezoceramic elements yields the Poisson’s ratio and the elastic modulus of the soils
quite easily, particularly for the soft clays and sands. 相似文献
96.
L. P. Sharma Nilanchal Patel P. Debnath M. K. Ghose 《Arabian Journal of Geosciences》2012,5(4):789-796
Hilly regions are prone to landslides that cause heavy losses of life and properties every year. A number of researches and
analyses are carried out in the GIS environment to identify landslide vulnerability in the region. The important conditioning
factors identified by the researchers are slope, geological, geomorphologic features, and land use coupled with triggering
factors like rainfall and a few of the anthropogenic activities. Soil forms the uppermost part of the earth crust, and it
is expected that various soil characteristics like depth, surface texture, depth texture, soil erosion, hydraulic conductivity,
stoniness, etc., play significant roles in causing landslide in the area. These factors have been ignored so far by most researchers
while identifying landslide hazard-prone areas. This paper attempts to assess the vulnerability status in parts of East Sikkim,
India, by integrating the influence of the various soil attributes. A composite index called soil stability value was determined
by aggregating the weights assigned to different soil parameters. Finally, based on the soil stability values, the study area
was classified into least vulnerable, moderately vulnerable, and most vulnerable zones of landslide occurrences. Comparison
between the vulnerability zones and the actual landslide occurrences yielded a 90% agreement with the density of landslides
in the most vulnerable zone, demonstrating the efficacy of soil characteristics as potential indicators of landslide events. 相似文献
97.
R. C. Patel H. N. Sinha Bhaiya Anupam Kumar Paramjeet Singh 《Journal of the Geological Society of India》2014,83(4):403-413
Apatite fission-track analysis has been applied to the Raniganj and Panchet formations of Raniganj basin of Gondwana Supergroup to unravel its thermal and provenance history. Apatite fission track age population from both Raniganj and Panchet formations indicate partial annealing and point to a maximum temperature of around ~100-110°C during their post depositional evolution. The sandstone of Raniganj Formation has five peak ages at 26.3, 59.3, 109.7, 173.7 and 299.9 Ma, while Panchet Formation has three peak ages at 25.4, 143.5 and 281.3 Ma. This implies that the provenance of the Raniganj Formation of late Permian and Panchet Formation of early Triassic changed obviously. According to thermotectonic evolution of the Gondwana basin, these apatites with different FT ages possibly represent different source components, although partial annealing had occurred to these apatites. Possibly all the apatites had transported from the Precambrian basement which was undergoing deformation due to Gondwana rifting initiated during Carboniferous period. Due to this, the basement was undergoing inhomogeneous thermal history which became source of sediments for Raniganj basin. Apatite FT ages of both Raniganj and Panchet formations have peak ages between 25 and 60 Ma, which perhaps recorded the cooling/uplift history during Cenozoic Alpine-Himalayan orogeny. Given a palaeo-thermal gradient of 40° C/km, it can be deduced that the Raniganj basin has uplifted about 3km at an average rate of about 0.09mm/a since 25–60 Ma. 相似文献
98.
M. Patel R. D. Oudmaijer J. S. Vink J. C. Mottram B. Davies 《Monthly notices of the Royal Astronomical Society》2006,373(4):1641-1647
We aim to characterize the current status of knowledge on the accuracy of open-cluster parameters such as the age, reddening and distance. These astrophysical quantities are often used to study the global characteristics of the Milky Way down to the very local stellar phenomena. In general, the errors of these quantities are neglected or set to some kind of heuristic standard value. We attempt to give some realistic estimates for the accuracy of available cluster parameters by using the independently derived values published in the literature. In total, 6437 individual estimates for 395 open clusters were used in our statistical analysis. We discuss the error sources depending on theoretical as well as observational methods and compare our results with those parameters listed in the widely used catalogue by Dias et al. In addition, we establish a list of 72 open clusters with the most accurate known parameters which should serve as a standard table in the future for testing isochrones and stellar models. 相似文献
99.
Patel NILANCHAL 《中国地理科学(英文版)》2006,(1)
1INTRODUCTIONMandelbrot stated the uncertainty of the length of a coastline in his paper "How long is the coast of Britain? Statistical self-similarity and fractional dimension" pub- lished in Science in 1967 (MANDELBROT, 1967). The concepts of fractal and fractal dimension were presented for the first time in that paper and have been applied to quantitatively describing the difference of crooked coastlines of British and South Africa. Compared with the Euclidean geometry with more… 相似文献
100.