Derivation of crop phenological parameters using multi-date SPOT-VGT-NDVI data: A case study for Punjab     

Gargi Upadhyay  S. S. Ray  Sushma Panigrahy 《Journal of the Indian Society of Remote Sensing》2008,36(1):37-50

Crop phenological parameters, such as the start and end time of the crop growth, the total length of the growing season, time of peak vegetation and rate of greening and senescence are important for planning crop management and crop diversification/intensification. Multi-temporal remote sensing data provides opportunity to characterize the crop phenology at regional level. This study was conducted during the kharif season of the year 2001–02 for Punjab. The ten-day Normalised Difference Vegetation Index (NDVI) composite products, with 1 km spatial resolution, available from the Vegetation sensor onboard SPOT4 were used for the study. Twenty-one temporal datasets from May 1, 2001 to November 21, 2001 were used. Logical modelling approach was followed to compute the minimum and maximum NDVI, the amplitude of NDVI, the threshold NDVI during sowing and harvest, the crop duration, integrated NDVI and skewness of profile. The analysis showed that before July beginning, in the whole of Punjab, sowing/planting was over. It was found that the crop emergence in the eastern part of the state started earlier than the western region. The maximum NDVI, which represented peak vegetative stage, was above 0.7 and occurred mostly during August. The duration of crops ranged between 90–140 days, with majority between 110–120 days. Total integrated NDVI in Punjab was generally above 60. Using principal component analysis and divergence analysis seven best metrics were selected for crop discrimination.  相似文献   

A 300-day periodicity of Cyg X-1     

R. K. Manchanda 《Astrophysics and Space Science》1983,91(2):455-460

A possible evidence of a 300 d period in the hard X-ray intensity of CygX-1 is deduced by a re-analysis of the available data between 1964 and 1978. It is suggested that the long term periodicity may be due to the presence of a third body in the system which will also explain in a natural way the large mass problem is assigned to the X-ray source.  相似文献   

Pulse profile of Her X-1 in hard X-rays     

R. K. Manchanda 《Astrophysics and Space Science》1976,44(1):L1-L4

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Size of the hard X-ray source in the Crab Nebula     

Y. Fukada  S. Hayakawa  I. Kasahara  F. Makino  Y. Tanaka  H. Akiyama  M. Matsuoka  J. Nishimura  M. Oda  M. Nakagawa  H. Sakurai  V. S. Iyenger  P. K. Kunte  R. K. Manchanda  B. V. Sreekantan 《Astrophysics and Space Science》1976,42(1):245-248

The size of the hard X-ray source in the Crab Nebula was observed with scintillation counters on board two balloons at a lunar occulatation on 24 January, 1975. The Gaussian width of the source is 34 (+17, –14) and the center thereof is offset from the pulsar by 6±4 at position angle 102°. The observed time profile can also be fitted to an alternative model of two line sources whose intensities are 48% at 11 and 25.5% at 7 on both sides of the pulsar.Paper presented at the COSPAR Symposium on Fast Transients in X- and Gamma-Rays, held at Varna, Bulgaria, 29–31 May, 1975.  相似文献   

Satellite stereo data for dem surfaces and derivatives     

Pramod Kumar  Sudhir Kumar  M. L. Manchanda 《Journal of the Indian Society of Remote Sensing》2004,32(1):81-90

Various attributes can be derived from Digital Elevation Model (DEM), which are essential to analyze watershed physical characteristics. This paper discusses utility and accuracy of satellite DEM surfaces and their derivatives. Facilities available in various software packages were compared to generate DEM from satellite data and other sources. For test site at Chamba, Uttaranchal, DEMs produced from various algorithms were evaluated for accuracy of surface and its derivatives. Most of the algorithms have shown correlation coefficient of 0.99 and above but the desirable maximum error in spot height (1/5 of contour interval) is not achieved. Slope and aspect produced from various algorithms were comparable around 70-80%. Comparison of DEM surface and its derivatives were attempted for test sites at Shimla and Nahan using IRS-1C and SPOT PAN stereo pair, respectively. Model accuracy has shown that error in height is higher than planimetry. Surface derivatives from stereo DEM for Shimla and Nahan test sites have shown an overall accuracy of 56.5% and 59.2% for slope; 49.79% and 71.21% for aspect and 74.15% for topographic level slicing, respectively. Accuracy has improved when observed class value was lowered or put-up by one unit.  相似文献   

Deposition and genesis of alluvial soils in the Indo-Gangetic Alluvial Plain Muzaffarnagar (U.P.)     

V. N. Garalapuri  M. L. Manchanda  R. L. Ahuja 《Journal of the Indian Society of Remote Sensing》1978,6(1):23-29

The area under study forms a part of the Indo-Gangetic Alluvial Plain, in Muzaffar Nagar District (Uttar Pradesh). To understand the relation of stratigraphy and geogenesis on one hand, and landscape and pedogensis on the other hand, the study was undertaken through a 40 km. long E-W. Cross-section of the area, with augering upto a depth of five metres or more, Aerial photographs (1:25,000) were used for delineating the major land forms and selection of cross-section and observations sites. Care was taken to cover all the main physiographic units occuring in the survey area. Four distinct depositional phases in Upper Alluvial Plain and two in Lower Alluvial Plain by Ganges, while first braided and then meandering have been recognized. Soil were classified according to Soil Taxonomy (1975), being Inceptisols and Alfisols in the Upper Alluvial Plain and Entisols in the Lower Alluvial Plain.  相似文献   

Static deformation of an orthotropic multilayered elastic half-space by two-dimensional surface loads     

Nat Ram Garg  Sarva Jit Singh  Sushma Manchanda 《Journal of Earth System Science》1991,100(2):205-218

The transfer matrix approach is used to solve the problem of static deformation of an orthotropic multilayered elastic half-space by two-dimensional surface loads. The general problem is decoupled into two independent problems. The antiplane strain problem and the plane strain problem are considered in detail. Integral expressions for displacements and stresses at any point of the medium due to a normal line load and a shear line load, acting parallel to a symmetry axis, are obtained. In the case of a uniform half-space, closed form analytic expressions for displacements and stresses are derived. The procedure developed is quite easy and convenient for numerical computations.  相似文献   

Drinking water quality in villages of southwestern Haryana,India: assessing human health risks associated with hydrochemistry   总被引：1，自引：0，他引：1  

Vinod K. Garg  Surindra Suthar  Sushma Singh  Aleenjeet Sheoran  Garima  Meenakshi  Sandeep Jain 《Environmental Geology》2009,58(6):1329-1340

The chemical quality of groundwater of western Haryana, India was assessed for its suitability for drinking purposes. A total of 275 water samples were collected from deep aquifer based hand-pumps situated in 37 different villages/towns of Bhiwani region. The water samples were analyzed for different physico-chemical properties, e.g., pH, total dissolved solids (TDS), total harness (TH), total alkalinity (TA), calcium, magnesium, carbonate, bicarbonate, sulphate, chloride and fluoride concentrations. In this study, the average TDS content was greater ranging 1,692 (Bhiwani block) to 2,560 mg l⁻¹ (Siwani block), and other important parameters of water, e.g., TA (442–1,232 mg l⁻¹), TH (437–864 mg l⁻¹) and bicarbonate (554–672 mg l⁻¹), were also higher than maximum permissible limit by WHO or BIS. The fluoride appeared as a major problem of safe drinking water in this region. We recorded greater fluoride concentration, i.e., 86.0 mg l⁻¹ from Motipura village that is highest fluoride level ever recorded for Haryana state. The average fluoride concentration ranged between 7.1 and 0.8 mg l⁻¹ in different blocks of western Haryana. On the basis of fluoride concentration, Siwani block showed the maximum number of water samples (84% of total collected samples) unsuitable for drinking purposes (containing fluoride >1.5 mg l⁻¹) followed by Charki Dadri block (58%), Bhiwani block (52%), Bawani Khera block (33%) and Loharu block (14%). This study clearly suggest that some health deteriorating chemicals in drinking water were at dangerous level and; therefore, water quality could be a major health threat for local residents of western Haryana. The high fluoride level in drinking water has posed some serious dental health risks in local residents.  相似文献   

Possible association of a hard X-ray source with a cosmic gamma-ray burst     

S. Biswas  R. K. Manchanda  B. V. Sreekantan 《Astrophysics and Space Science》1975,33(2):L15-L18

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Land use study in Mewat area,Haryana, using remote sensing techniques     

S. Natarajan  N. Y. Gajbe  M. L. Manchanda 《Journal of the Indian Society of Remote Sensing》1986,14(1):17-24

A soil and land use survey of Mewat area, Haryana, was carried out using the aerial photographs of 1:50,000. Four major physiographic units namely hills, piedmont plain, intermontante basin and Yamuna alluvial plain were recognised. The land use was studied in relation to the physiographic units. The legend adopted for land use classification has physiography at first level, utility at second level and management and identification at third and fourth levels respectively. Of the total area of 161,103 ha surveyed, 131,637 ha (81.72%) are cultivated. Of this 75,967 ha (47.16%) irrigated and 55,670 ha (34.56%) is unirrigated. Under uncultivated area, barren lands cover 14,224 ha (8.82%), forests occupy 3,463 ha (5.25%), settlements cover 3,300 (2.05%), water bodies occupy 1,312 ha (0.81%) and roads, railway lines, canals and drains constitute 2,167 ha (1.55%).  相似文献