T. P. Singh

Spectral response of rice crop and its relation to yield and yield attributes

Abstract Ground-based radiometric measurements were conducted on six varieties of rice crop during an entire growth cycle using a hand-held seven-band radiometer. Concomitant measurements of some of the yield attributes were also made. Spectral data were also collected on a single variety grown under 12 different fertilizer treatments. Spectral data have been correlated with leaf area index, total wet biomass, total dry biomass, plant water content and final grain, straw and total yield. The results show similar temporal spectral responses of all six varieties and a strong correlation of agronomic parameters with spectral parameters derived from the near-infrared and red radiances. Red and near-infrared radiance ratio and normalized differences were found sensitive to the N fertilizer application but not to the P and K fertilizers. Linear correlations were observed between spectral parameters and final grain, straw and total yield

DESIGN OF 35 GHZ GYROTRON FOR MATERIAL PROCESSING APPLICATIONS

The complete design of 35GHz, 200kW gyrotron for various material processing and heating applications is presented in this article. The components of the device, such as Magnetron Injection Gun, interaction cavity, collector and RF window, are designed for the TE03 mode. Various in-house developed codes (GCOMS, MIGSYN and MIGANS) and commercially available codes (MAGIC, EGUN and CST-MS) are used for the design purpose. A thorough sensitivity analysis of the gyrotron components is also carried out. The designed device shows the capability to generate more than 200kW of output power with more than 40% of e-ciency.

Spectral signature studies in optical region

Abstract Reflectance spectra of a large number of rock, vegetation and soil samples have been measured in the laboratory in the visible and near infrared wavelength regions. Procedures have been evolved to find optimum spectral bands for rock discrimination. ‘In situ’ reflectance measurements on different crops like wheat, paddy, millet, cotton, maize, groundnut etc. during their various growth stages have been carried out using hand-held radiometers. Recently measurements have been conducted over six wheat plots subjected to different irrigation schedules to see the effect of water stress on the signatures. Results show that the best period for monitoring water stress in wheat through remote sensing is 45–80 days after sowing.

Remote Sensing Data Acquisition, Platforms and Sensor Requirements

AbstractAlthough data available from various earth observation systems have been routinely used in many resource applications, however there have been gaps, and data needs of applications at different levels of details have not been met. There is a growing demand for availability of data at higher repetivity, at higher spatial resolution, in more and narrower spectral bands etc.Some of the thrust areas of applications particularly in the Indian context are;-Management of natural resources to ensure sustainable increase in agricultural production,-Study the state of the environment, its monitoring and assessment of the impact of. various development actions on the environment,-Updating and generation of large scale topographical maps.-Exploration/exploitation of marine and mineral resources and-Operational meteorology and studying various land and oceanic processes to understand/predict global climate changes.n Each of these thrust area of application has many components, related to basic resource areas such as agriculture, forestry, water resources, minerals, marine resources etc. and the field of cartography. Observational requirements for major applications have been summarized as under.Monitoring vegetation health from space remains the most important observational parameter with applications, in agriculture, forestry, environment, hydrology etc. Vegetation extent, quantity and temporal changes are the three main requirements which are not fully realized with RS data available. Vegetation productivity, forest biomass, canopy moisture status, canopy biogeochemistry are some examples. Crop production forecasting is an important application area. Remotely sensed data has been used for identification of crops and their acreage estimation. Fragmented holdings, large spread in crop calendars and different management practices continue to pose a challenge lo remote sensing. Remotely sensed data at much higher spatial resolution than hitherto available as well as at greater repetivity are required to meet this need. Non-availability of cloud-free data in the kharif season is one of the serious problems in operational use of remote sensing for crop inventory. Synthetic aperture radar data al X & Ku bands is necessary to meet this demand. Nutrient stress/disease detection requires observations in narrow spectral bands. In case of forestry applications, multispectral data at high spatial resolution of the order of 5 to 10 metres is required to make working plans at forest compartment level. Observations from space for deriving tree height are required for volume estimation. Observations in the middle infrared region would greatly enhance capability of satellite remote sensing in forest fire detection. Temporal, spatial and spectral observational requirements in various applications on vegetation viewing are diverse, as they address processes at different spatial and time scales. Hence, it would be worthwhile to address this issue in three broad categories.a) Full coverage, moderate spatial resolution with high repetivity (drought, large scale deforestation, forest phenology....).b) Full coverage, moderate to high spatial resolution and high repetivity (crop forecasting, vegetation productivity).c) Selected viewing at high spatial resolution, moderate to high repetivity and with new dimensions to imaging (narrow spectral bands, different viewing angles).A host of agrometeorological parameters are needed to be measured from space for their effective use in development of yield models. Estimation of root-zone soil moisture is an important area requiring radar measurements from space. Surface meteorological observations from space at the desired spatial and temporal distributions has not developed because of heavy demands placed on the sensor as well as analytical operational models. Agrometeorology not only provides quantitative inputs to other applications such as crop forecasting, hydrological models but also could be used for farmer advisory services by local bodies.Mineral exploration requires information on geological structures, geomorphology and lithology. Surface manifestation over localized regions requires large scale mapping while the lithology can be deciphered from specific narrow bands in visible. NIR, MIR and TIR regions. Sensors identified for mapping/cartography in conjunction with imaging spectrometer would seem to cover requirements of this application. Narrow spectral bands in the short regions which provide diagnostics of relevant geological phenomenon are necessary for mineral exploration. Thermal inertia measurements help in better discrimination of different rock units. Measurements from synthetic aperture data which would provide information on geological structures and geomorphology are necessary for mineral exploration.The applications related to marine environment fall in three major areas: (i) Ocean colour and productivity, biological resources; (ii) Land-ocean interface, this includes coastal landforms, bathymetry, littoral transport processes, etc. and; (iii) Physical oceanography, sea surface temperature, winds, wave spectra, energy and mass exchange between atmosphere and ocean. Measurement of chlorophyll concentration accurately on daily basis, sea surface temperature with an accuracy of 0.5 °K. and information on current patterns arc required for developing better fishery forecast models. Improved spatial resolution data are desirable for studying sediment and other coastal processes.Cartography is another important application area. The major problems encountered in relation to topographic map updation are location and geometric accuracy and information content. Two most important requirements for such an application are high spatial resolution data of 1 to 2 metre and stereo capability to provide vertical resolution of 1 metre. This requirement places stringent demands on the sensor specifications, geometric processing, platform stability and automated digital cartography.The requirements for the future earth observation systems based on different application needs can be summarized as follows:•Moderate spatial resolution (l50-300m), high repetivity (2 Days), minimum set of spectral bands (VIS, NIR, MIR. TIR) full coverage.•Moderate to high spatial resolution (20-40m), high repetivity (4-6 Days), spectral bands (VIS, MR, MIR, TIR) full coverage.•High spatial resolution (5-10m) muitispectral data with provision for selecting specific narrow bands (VIS, N1R. MIR), viewing from different angles.•Synthetic aperture radar operating in at least two frequencies (C, X, Ku), two incidence angles/polarizations, moderate to high spatial resolution (20-40m), high repetivity (4-6 Days).•Very high spatial resolution (1-2m) data in panchromatic band to provide terrain details at cadastral level (1:10,000).•Stereo capability (1-2m height resolution) to help planning/execution of development plans.•Moderate resolution sensor operating in VIS, NIR, MIR on a geostationary platform for observations at different sun angles necessary for the development of canopy reflectance inversion models.• Diurnal (at least two i.e. pre-dawn and noon) temperature measurements of the earth surface.•Ocean colour monitor with daily coverage.•Multi-frequency microwave radiometer, scatterometer. altimeter, atmospheric sounder, etc.

Land-use survey of Idukki District

Abstract The growing population pressure and limited availability of land necessitates proper utilization of the available land through scientific land-use planning. Realizing this fact, a project using multiband aerial photography was taken up with following objectives: identification and mapping of areas under various land uses, study of geomorphology, identification of potential groundwater areas and identification of areas requiring soil conservation and reclamation measures. The major land-use classes mapped are agriculture, forest, wasteland, water bodies and public use. These are further subclassified. Some of the important observations are the reduction in the area under forest and the existence of a large area under wasteland. Geomorphological maps prepared depict slope, relief, drainage and vegetation. With the help of structural and geomorphological maps, the technique of identifying potential groundwater areas has been demonstrated. The land-use maps have a classification accuracy of 86 per ce...

Particle-in-Cell Analysis of 1 MW/110GHz Gyrotron Interaction Cavity

Abstract In this paper, the design and numerical analysis of the interaction cavity for 1MW, 110 GHz gyrotron is presented. The in-house developed code GCOMS and the commercially available 3D particle-in-cell simulation code MAGIC have been used for the mode selection and optimization of the interaction cavity parameters respectively. TE22,6 mode has been chosen as the operating mode. The cold cavity and the beam-wave interaction analysis have been carried out for the TE22,6 mode and the output power and the efficiency have been computed. The sensitivity analysis of the output power and the efficiency has also been performed with respect to the cavity geometry and the electron beam parameters. More than 1MW output power has been achieved at 110 GHz frequency with the selected operating mode.

Cold cavity analysis for 35 GHz gyrotron interaction cavity using free space method

The interaction cavity simulated, designed and fabricated for the 35 GHz gyrotron is verified experimentally. Free space method for the Q value and resonant frequency measurement is used in the experiments. The WR22 waveguide based antenna system, Agilent Vector Network Analyzer are used as the experimental set-up in the cavity measurement. The simulation results for the same cavity are also obtained by using the electromagnetic simulator MAGIC for the comparison.

P3-10: Design of interaction cavity for 120 GHz, 1 MW gyrotron

A weakly tapered interaction cavity has been designed to excite TE22,6 operating mode at the fundamental harmonic number for 120 GHz, 1 MW gyrotron. A MATLAB code has been developed to synthesize cavity geometry and selection of operating mode. The cold cavity analysis and the beam-wave interaction were carried out using the commercially available PIC code MAGIC. The output power above 1 MW has been achieved at guiding cavity magnetic field 4.82 T.

Sensitivity Analysis of Electron Beam Velocity Ratio for 42 GHz, 200 kW Gyrotron

A 42 GHz, 200 kW gyrotron has been designed recently for Indian TOKAMAK system. The velocity ratio of the electron beam (a) is a critical parameter for high efficiency and high power gyrotron operation. The velocity ratio varies with the variation of the beam parameters. The output power and efficiency of gyrotron depends highly on the velocity ratio. This paper presents the sensitivity analysis of velocity ratio with respect to beam parameters, space charge parameters, start up scenario in terms of start oscillation current, output power and efficiency. Index Terms – Microwave device, gyrotron, velocity ratio, MIG, interaction cavity, start oscillation current

District level planning : a case study for the Panchmahals district using remote sensing and Geographic Information System techniques

A study for District Level Planning was carried out in the Panchmahals district, Gujarat, using the concepts of the Composite Land Development Unit (CLDU) and the Service Centre Hierarchy (SCH) for natural and socioeconomic resources, respectively. The CLDU map was derived from slope, soil, ground water prospect and land-use information using GIS techniques. Alternate land-use sites for grassland, horticulture, afforestation were recommended based upon the soil-slope conditions of the CLDUs. Priority sub-watersheds in the district were identified for soil conservation measures. Analysis on SCH was based upon composite amenity index (AI).