Remote Sensing and Geographical Information System for canopy cover mapping     

Ndr Krishna  A K Maji  YVN Krishna Murthy  BSP Rao 《Journal of the Indian Society of Remote Sensing》2001,29(3):107-113

Availability of remote sensing data from earth observation satellites has made it convenient to map and monitor land use/land cover at regional to local scales. A land cover map is very critical for a various planning activities including watershed planning. The spectral and spatial resolutions are major constraints for mapping the crop resources at microlevel. The cropping pattern zones have been mapped using the false color composite, physiography, irrigation and toposheets. The IRS LISS-III data is classified into various categories depending on spectral reflectance from crop canopy and are overlaid on cropping zones map. The re-classified resultant map provides land use/land cover information including dominant cropping systems. The canopy cover is estimated monthly considering the crop calendar for the area.  相似文献   

Remote sensing approach for watershed based resources management in the Sikkim Himalaya: A case study     

Akhouri Pramod Krishna 《Journal of the Indian Society of Remote Sensing》1996,24(2):71-83

Integrated and environmentally sustainable development strategies have become inevitable for micro-level planning these days. The usefulness of remotely sensed data from earth resource satellites for watershed management is discussed for an eastern Himalayan watershed covering 39.09 km² area. The biophysical conditions were assessed based on field experience. The SPOT HRV-I MLA and PLA scenes were interpreted for land use/cover categories and associated characteristics. These parameters were found to be significant towards evolving the management priorities for development of agriculture, soil conservation, afforestation and rain water harvesting structures in ecologically fragile Himalayan region. The remote sensing inputs were important in deriving the relevant details faster and precisely.  相似文献   

The value ofC efor the Arabian Sea during summer monsoon     

A. Suryachandra Rao  Y. Sadhuram  V. V. Gopala Krishna 《Journal of Earth System Science》1995,104(4):607-611

We estimate, from the moisture budget the bulk aerodynamic coefficient for latent heat flux (C _e) during the monsoon season over the central Arabian Sea. The average value ofC _eunder active monsoon conditions was found to be 2.25 × 10⁻³ which is nearly 60% higher than those previously used.  相似文献   

Finite strain theory of love waves     

Krishna De 《Pure and Applied Geophysics》1970,80(1):114-123

Summary The propagation of Love waves is discussed on the basis of finite strain theory. The primary Love wave is found to be associated with a secondary Rayleigh wave and a tertiary Love wave. Numerical calculations are presented for two values of the wave-velocity; the results show that the theory of Love waves based on infinitesimal strain, is not applicable to short period waves.  相似文献   

Refinement of the synthetic hydroxyapatite cell parameters     

Vijay Mohan Bhatnagar 《Contributions to Mineralogy and Petrology》1969,22(4):375-378

High-precision, computer-refined values of the cell parameters of calcium hydroxyapatite, Ca₁₀(PO₄)₆(OH)₂, have been determined with an X-ray diffractometer, internally standardized by means of sodium chloride. The results obtained are as follows: a ₀=9.4192 Å c ₀/a ₀=0.731 c ₀=6.8867 Å volume=529.2 ų The apatite work was supported by a research grant DE-02105 from the United States Department of Health, Education, and Welfare. I am very grateful to Dr. W. R. Liebenberg, Dr. S. A. Hiemstra and Dr. H. V. R. von Rahden of National Institute for Metallurgy, South Africa for their valuable help and interest and Prof. Nelson Fuson and Prof. James R. Lawson for advice and discussion.  相似文献   

Effects of E-region electric fields on F-region parameters at the magnetic equator     

K.Sen Gupta  B.V.Krishna Murthy 《Planetary and Space Science》1973,21(12):2227-2232

The effects of E-region electric fields on F-region parameters like height of constant electron density contours (h_N) and semi-thickness, at an equatorial station, Trivandrum, are investigated. The E-region east-west electric field (E_y) has been deduced using the horizontal magnetic field values from the ground magnetograms. It is found that the semi-thickness parameter and h_N follow closely the E-region electric field (E_y) variations in the forenoon and noon periods. In the afternoon, it is shown that there is close association between h_N and E_y, when the electric field variations are large. On a day-to-day basis also, h_N and the E-region electric field show very good correlation in the forenoon and noon hours. It is also shown that higher levels are affected more than the lower levels in the F-region by E_y.  相似文献   

Nature of the 400-km Discontinuity in the Earth's Mantle     

K. L. Kaila  V. G. Krishna 《Geophysical Journal International》1976,46(1):185-188

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Use of Roche coordinates in the problems of small oscillations of tidally-distorted stellar models     

C. Mohan  V. P. Singh 《Astrophysics and Space Science》1979,60(2):423-430

Kopal's method of Roche coordinates used by us in an earlier paper (Mohan and Singh, 1978) to study the problems of small oscillations of tidally-distorted stars has been extended further to take into account the effect of second-order terms in tidal distortion. Our results show that the effect of including terms of second order of smallness in tidal distortion in the metric coefficients of the Roche coordinates of tidally distorted stars is quite significant, especially in case of stars with extended envelopes and (or) larger values of the mass ratio of the companion star producing tidal distortion. Some of the models which were earlier found stable against small perturbations now become dynamically unstable with the inclusion of the terms of second order of smallness in tidal effects.At present on leave of absence with the department of Mathematics, College of Science, Baghdad, Iraq.  相似文献   

Aerosol optical depth, physical properties and radiative forcing over the Arabian Sea     

S. K. Satheesh  K. Krishna Moorthy  Y. J. Kaufman  T. Takemura 《Meteorology and Atmospheric Physics》2006,91(1-4):45-62

Summary The Arabian Sea region (4° N–20° N to 50° E–78° E) has a unique weather pattern on account of the Indian monsoon and the associated winds that reverse direction seasonally. The aerosol data, collected using ship-borne and island platforms (for 8 years from 1995 to 2002) along with MODIS (onboard TERRA satellite) data (from 2000 to 2003) have been used to evolve a comprehensive characterisation of the spatial and temporal variation in the physical, chemical, and radiative properties of aerosols over the Arabian Sea. The aerosol optical depth (AOD) was found to increase with latitude between the equator and 12° N. Over the northern Arabian Sea (regions lying north of 12° N), AODs do not show significant latitudinal variations; the average aerosol optical depth for this region was 0.29±0.12 during winter monsoon season (WMS; November to March) and 0.47±0.14 during summer monsoon season (SMS; April/May to September). The corresponding Angstrom exponents were 0.7±0.12 and 0.3±0.08, respectively. The low values of the exponent during SMS indicate the dominance of large aerosols (mainly dust particles >1 μm). The latitudinal gradient in AOD in the southern Arabian Sea is larger during SMS compared to WMS. The size distribution of aerosols shows two well-defined modes, one in the accumulation size regime and the other in the coarse size regime. During WMS, a third mode (nucleation) also appears in the sub micron range below ∼0.1 μm. The single scattering albedo does not show significant seasonal variations (remains within ∼0.93 to 0.98 through out the year). During WMS (SMS), top of the atmosphere diurnally averaged aerosol forcing remains around −6.1 (−14.3)W m⁻² over the northern Arabian Sea up to around 12° N and decreases southwards till it attains a value of −3.8 (−3.4)W m⁻² at the equator. The surface forcing remains around −16.2(−15.2)W m⁻² over the northern Arabian Sea up to 12° N and decreases southwards to a value of −5.5 (−3.5)W m⁻² at the equator. Over the north Arabian Sea, instantaneous forcing (flux change) at the surface can be as high as −50 W m⁻². The instantaneous forcing decreases with latitude in the southern Arabian Sea at a rate of ∼3 W m⁻²deg⁻¹.  相似文献   

Pattern and genesis of lineaments in and across son-Narmada lineament zone in a part of central India around Renukoot,district Sonbhadra,U.P.     

Kshitij Mohan  Vaibhava Srivastava  C. K. Singh 《Journal of the Indian Society of Remote Sensing》2007,35(2):193-200

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