Download or read book A Polarization Diversity Meteorological Radar System written by James I. Metcalf and published by . This book was released on 1987 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The AFGL 10-cm Doppler weather radar was modified to enable the measurement of the differential reflectivity between horizontal and vertical polarizations in addition to the absolute reflectivity and the Doppler mean velocity and spectrum variance. Polarization switching is achieved by means of a diplexer, which separates at the antenna the transmitted signals of two frequencies, 2710 and 2760 MHz, and permits nearly simultaneous transmission of signals of orthogonal polarizations. Signals of these frequencies can be transmitted either with horizontal and vertical polarization, respectively, or with left and right circular, polarization, respectively. We describe the design and performance of the diplexer and the performance of the real-time data processor, present examples of meteorological measurements, and discuss future developments of the radar system. Keywords: Polarization diversity weather radar, Dual polarization radar, and Polarization switching.
Download or read book A Polarization Diversity Meteorological Radar System written by James I. Metcalf and published by . This book was released on 1987 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The AFGL 10-cm Doppler weather radar was modified to enable the measurement of the differential reflectivity between horizontal and vertical polarizations in addition to the absolute reflectivity and the Doppler mean velocity and spectrum variance. Polarization switching is achieved by means of a diplexer, which separates at the antenna the transmitted signals of two frequencies, 2710 and 2760 MHz, and permits nearly simultaneous transmission of signals of orthogonal polarizations. Signals of these frequencies can be transmitted either with horizontal and vertical polarization, respectively, or with left and right circular, polarization, respectively. We describe the design and performance of the diplexer and the performance of the real-time data processor, present examples of meteorological measurements, and discuss future developments of the radar system. Keywords: Polarization diversity weather radar, Dual polarization radar, and Polarization switching.
Download or read book Precipitation and Lightning Measurements by Polarization Diversity Radar written by James I. Metcalf and published by . This book was released on 1988 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of a Polarization Diversity Weather Radar Design written by J. S. Ussailis and published by . This book was released on 1982 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report focuses not only on a design for a pulse-to-pulse polarization diversity modification of the Air Force Geophysics Laboratory (AFGL) S-band Doppler weather radar, but also upon the meteorological and technical requirements of such a radar. The theoretical aspects of and physical limitations imposed by the polarization diversity requirement are presented independently of this design and as a result are applicable towards the development of any similar system. The antenna modification could also be applied towards the general case, excepting the condition imposed in this design that the present twenty-four foot diameter reflector be retained. Formulae are developed to demonstrate the various uncertainties for the system as a whole and the antenna in particular. Tradeoffs between the various meteorological measurement goals vs available and constructible radio frequency components are presented.
Download or read book Polarization Diversity Addition to the 10 Centimeter Doppler Weather Radar written by James S. Ussailis and published by . This book was released on 1984 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research performed was that of providing antenna modifications for a polarization diversity addition to the; AFGL 10 centimeter DOPPLER WEATHER RADAR. Described within are the ANTENNA FEED DESIGN (POTTER HORN), the conversion of the antenna form a prime focus to a Cassegrain Configuration, the results of the feed horn RF measurements, the construction of the POLARIZER ASSEMBLY, and the installation and testing of the antenna system. Keywords include: Polarization; Potter horn; Weather radar; Polarized unit; and Antenna testing.
Download or read book Precipitation and Lightning Measurements by Polarization Diversity Radar written by James I. Metcalf and published by . This book was released on 1988 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Consulting During Development of an Instrument Coherent Polarization Diversity Meteorological Radar written by Eugene Ferguson Greneker and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarization Diversity Addition to 10 Centimeter Doppler Weather Radar written by James S. Ussailis and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Polarization diversity Radar to Meteorology written by James I. Metcalf and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Precipitation and Lightning Measurements by Polarization Diversity Radar written by James I. Metcalf and published by . This book was released on 1988 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Observations of severe convective storms in June 1987 by an 11-cm polarization diversity Doppler radar are described. Specific features include heavy rain, large hail, melting ice particles, lightning, and signal propagation effects. Of particular interest are the first measurements of the polarization differential reflectivity of lightning channels, which reveal the predominant orientations of the channels. Successive radar pulses were transmitted with alternating horizontal and vertical polarization by means of a high-power microwave switch to permit derivation of the differential reflectivity with a small standard error of estimate.
Download or read book Introduction to Dual Polarization Weather Radar written by V. Chandrasekar and published by Cambridge University Press. This book was released on 2023-08-31 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: An interdisciplinary, easy-to-understand introduction, covering fundamental theory and practical applications. Featuring numerous operational examples, and interpretation of radar observations, this is a perfect resource for scientists and engineers working on or with radars, as well as senior undergraduate and graduate students.
Download or read book A Polarization Diversity Radar Data Processor written by and published by . This book was released on 1983 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: A real time data processor has been designed for use with the AFGL 10-cm Doppler weather radar which is to be operated with alternating transmission of horizontally and vertically polarized signals. In this mode of operation the reception of backscattered signals of polarizations identical to those of the transmitted signals allows the computation of the differential reflectivity between the two polarizations in addition to the absolute reflectivity and the Doppler mean velocity and variance. The switching of transmitted polarization introduces difficulties in the estimation of the autocovariance of the received signals, from which the Doppler velocity parameters are derived. The processor design and the allowed modes of radar operation circumvent these difficulties. This report describes the processing algorithms theoretically and presents details of the implementation of these algorithms in hardware. (Author).
Download or read book Applications of Polarization diversity Radar and Lidar in Meteorology written by James I. Metcalf and published by . This book was released on 1977 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation and Interpretation of Polarization Diversity Radar Spectral Functions written by James I. Metcalf and published by . This book was released on 1983 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical model was developed to simulate the power spectra, cross-spectrum, and derived functions obtainable from a coherent polarization diversity radar. The model was used to investigate the effects of air velocity variance, differential propagation, and noise on the spectral functions. Input parameters include radar wavelength, elevation angle, air velocity variance, rainfall rate, propagation distance, fraction of scatterers having a preferred orientation, and relative noise level. Results of calculations for 8.6 mm and 7.5 cm wavelengths are illustrated. These are compared with the functional forms obtained from theory and discussed in terms of the meteorological information derivable from them. The forms of the spectral power ratio and the cross-spectral amplitude ratio are strongly affected by air velocity variance and by noise. However, it appears possible to derive a good estimation of the Doppler air velocity from the power spectra. The cross-spectral amplitude ratio may be of more general value in analysis than previously thought, because its Doppler velocity domain is greater than that of the spectral power ratio in the presence of radar system noise. The absolute error of the propagation term estimated from the cross-spectral amplitude ratio is not strongly dependent on the rainfall rate or propagation distance.
Download or read book Weather Radar Technology Beyond NEXRAD written by National Research Council and published by National Academies Press. This book was released on 2002-07-31 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Weather radar is a vital instrument for observing the atmosphere to help provide weather forecasts and issue weather warnings to the public. The current Next Generation Weather Radar (NEXRAD) system provides Doppler radar coverage to most regions of the United States (NRC, 1995). This network was designed in the mid 1980s and deployed in the 1990s as part of the National Weather Service (NWS) modernization (NRC, 1999). Since the initial design phase of the NEXRAD program, considerable advances have been made in radar technologies and in the use of weather radar for monitoring and prediction. The development of new technologies provides the motivation for appraising the status of the current weather radar system and identifying the most promising approaches for the development of its eventual replacement. The charge to the committee was to determine the state of knowledge regarding ground-based weather surveillance radar technology and identify the most promising approaches for the design of the replacement for the present Doppler Weather Radar. This report presents a first look at potential approaches for future upgrades to or replacements of the current weather radar system. The need, and schedule, for replacing the current system has not been established, but the committee used the briefings and deliberations to assess how the current system satisfies the current and emerging needs of the operational and research communities and identified potential system upgrades for providing improved weather forecasts and warnings. The time scale for any total replacement of the system (20- to 30-year time horizon) precluded detailed investigation of the designs and cost structures associated with any new weather radar system. The committee instead noted technologies that could provide improvements over the capabilities of the evolving NEXRAD system and recommends more detailed investigation and evaluation of several of these technologies. In the course of its deliberations, the committee developed a sense that the processes by which the eventual replacement radar system is developed and deployed could be as significant as the specific technologies adopted. Consequently, some of the committee's recommendations deal with such procedural issues.
Download or read book Theory of Coherent Polarization diversity Radar in Meteorology written by James I. Metcalf and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarimetric Doppler Weather Radar written by V. N. Bringi and published by Cambridge University Press. This book was released on 2001-08-30 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 2001 book provides a detailed introduction to the principles of Doppler and polarimetric radar, focusing in particular on their use in the analysis of weather systems. The design features and operation of practical radar systems are highlighted throughout the book in order to illustrate important theoretical foundations. The authors begin by discussing background topics such as electromagnetic scattering, polarization, and wave propagation. They then deal in detail with the engineering aspects of pulsed Doppler polarimetric radar, including the relevant signal theory, spectral estimation techniques, and noise considerations. They close by examining a range of key applications in meteorology and remote sensing. The book will be of great use to graduate students of electrical engineering and atmospheric science as well as to practitioners involved in the applications of polarimetric radar systems.
