Download or read book Global Morphology of Ionospheric Scintillations II written by Jules Aarons and published by . This book was released on 1975 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Updating a review of the global morphology of ionospheric scintillations published in 1971, this study adds additional experimental studies on familiar topics to newer types of measurements of ionospheric irregularities, including in situ experiments and artificial heating of the F-layer.
Download or read book Global Morphology of Ionospheric Scintillations written by Jules Aarons and published by . This book was released on 1970 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amplitude fluctuations produced by small irregularities in electron density in the F-layer of the ionosphere (at 300 to 400 km height) can be a problem to communication and navigation systems in the VHF-UHF range. Recent measurements, primarily by AFCRL, are shown with emphasis on results at high and equatorial latitudes. At high latitudes an irregularity region exists whose lower boundary reaches 57 degrees invariant latitude near midnight. During magnetic storms the boundary descends to lower latitudes and the fading becomes deeper. Over the polar cap scintillations are somewhat diminished. When observing synchronous satellites through the irregularity region, deep and fast fading is frequently seen, with fade rates to one per second. Irregularities produce deep scintillations in the VHF range plus or minus 15 degrees from the geomagnetic equator. In equatorial regions maximum occurrence of high level scintillations takes place between 2100 and 2400 local time during the equinoxes; a minimum occurrence is observed during the solstices. When the sunspot number decreases, the equatorial irregularity region spreads and becomes larger. The data for various latitudes has been placed in statistical form, that is, distribution of amplitudes for 15-min samples as well as for periods of 1 yr and longer. (Author).
Download or read book Space Physics and Aeronomy Ionosphere Dynamics and Applications written by Chao Huang and published by John Wiley & Sons. This book was released on 2021-05-11 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive review of global ionospheric research from the polar caps to equatorial regions It's more than a century since scientists first identified the ionosphere, the layer of the Earth’s upper atmosphere that is ionized by solar and cosmic radiation. Our understanding of this dynamic part of the near-Earth space environment has greatly advanced in recent years thanks to new observational technologies, improved numerical models, and powerful computing capabilities. Ionosphere Dynamics and Applications provides a comprehensive overview of historic developments, recent advances, and future directions in ionospheric research. Volume highlights include: Behavior of the ionosphere in different regions from the poles to the equator Distinct characteristics of the high-, mid-, and low-latitude ionosphere Observational results from ground- and space-based instruments Ionospheric impacts on radio signals and satellite operations How earthquakes and tsunamis on Earth cause disturbances in the ionosphere The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals. Find out more about the Space Physics and Aeronomy collection in this Q&A with the Editors in Chief
Download or read book Model of Equatorial Scintillations from in Situ Measurements written by Sunanda Basu and published by . This book was released on 1976 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: In situ measurements of F-region irregularity amplitude and ambient electron density made by the retarding potential analyzer (RPA) on OGO-6 near perigee altitude of 400 km have been utilized to derive the variation of electron density deviation over the equatorial region. Based on these measured electron density deviations and other assumed model parameters, including a three-dimensional power-law form of irregularity spectrum of index 4, a model of equatorial scintillations is developed in the framework of diffraction theory. The percentage occurrence contours of estimated equatorial scintillations greater than or equal to 4.5 dB at 140 MHz during 1900 to 2300 LMT for the period November to December 1969 and 1970 have been derived. The model is found to depict a pronounced longitude variation with the scintillation belt width and percentage occurrence being maximum over the African sector. The latitude extent of the spatial scintillation belt narrows over the American sector without much decrease in the scintillation occurrence whereas over the Indian and Far Eastern sectors both the extent and the occurrence are found to decrease. The percentage occurrence of scintillations estimated from this model is found to be consistent with VHF scintillation measurements at Ghana, Huancayo, and Calcutta. In addition, the model was found to be in qualitative agreement with GHz observations at various longitudes made by the COMSAT group. The effect of varying model parameters on scintillation estimates at VHF, UHF and GHz are discussed. Implications of the observed longitudinal variation of scintillations on current theories of equatorial irregularity formation are indicated. (Author).
Download or read book Ionospheric Scintillation Effects on VHF UHF Communication Systems written by H. E. Whitney and published by . This book was released on 1976 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tropospheric and Ionospheric Effects on Global Navigation Satellite Systems written by Timothy H. Kindervatter and published by John Wiley & Sons. This book was released on 2022-08-23 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tropospheric and Ionospheric Effects on Global Navigation Satellite Systems Explore atmospheric effects on radio frequency propagation in the context of Global Navigation Satellite System communication In Tropospheric and Ionospheric Effects on Global Navigation Satellite Systems, a team of distinguished researchers deliver an accessible and authoritative introduction to all scientifically relevant effects caused by the ionosphere and troposphere on GNSS RF signals. The book explores the origin of each type of propagation effect and explains it from a fundamental physical perspective. Each of the major methods used for the measurement, prediction, and mitigation of ionospheric and tropospheric effects on GNSS are discussed in detail. The authors also provide the mechanisms that drive ionization and plasma transport in the ionosphere, propagation phenomena (including scattering, absorption, and scintillations), and the predominant predictive models used to predict ionospheric propagation effects. With an emphasis on global navigation satellite systems, the book discusses the US Standard Atmosphere, a general reference model for characteristics of the unionized atmosphere. It also considers: Thorough introductions to the Global Positioning System and the principles of GNSS positioning Comprehensive explorations of tropospheric propagation and predictive models of the troposphere Practical discussions of the physics of the ionosphere, experimental observation of the ionosphere, and ionospheric propagation In-depth examinations of predictive models of the ionosphere, including group delay models for single-frequency GNSS receivers Ideal for engineers and research scientists with a professional or personal interest in geophysics, RF propagation, and GNSS and GPS applications, Tropospheric and Ionospheric Effects on Global Navigation Satellite Systems will also earn a place in the libraries of undergraduate and graduate students studying RF propagation or GNSS.
Download or read book Report of NRL Progress written by Naval Research Laboratory (U.S.) and published by . This book was released on 1974 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Air Force Surveys in Geophysics written by and published by . This book was released on 1972 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interferometry and Synthesis in Radio Astronomy written by A. Richard Thompson and published by Springer. This book was released on 2017-02-22 with total page 910 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is open access under a CC BY-NC 4.0 license. The third edition of this indispensable book in radio interferometry provides extensive updates to the second edition, including results and technical advances from the past decade; discussion of arrays that now span the full range of the radio part of the electromagnetic spectrum observable from the ground, 10 MHz to 1 THz; an analysis of factors that affect array speed; and an expanded discussion of digital signal-processing techniques and of scintillation phenomena and the effects of atmospheric water vapor on image distortion, among many other topics. With its comprehensiveness and detailed exposition of all aspects of the theory and practice of radio interferometry and synthesis imaging, this book has established itself as a standard reference in the field. It begins with an overview of the basic principles of radio astronomy, a short history of the development of radio interferometry, and an elementary discussion of the operation of an interferometer. From this foundation, it delves into the underlying relationships of interferometry, sets forth the coordinate systems and parameters to describe synthesis imaging, and examines configurations of antennas for multielement synthesis arrays. Various aspects of the design and response of receiving systems are discussed, as well as the special requirements of very-long-baseline interferometry (VLBI), image reconstruction, and recent developments in image enhancement techniques and astrometric observations. Also discussed are propagation effects in the media between the source and the observer, and radio interference, factors that limit performance. Related techniques are introduced, including intensity interferometry, optical interferometry, lunar occultations, tracking of satellites in Earth orbit, interferometry for remote Earth sensing, and holographic measurements of antenna surfaces. This book will benefit anyone who is interested in radio interferometry techniques for astronomy, astrometry, geodesy, or electrical engineering.
Download or read book The Theory of Scintillation with Applications in Remote Sensing written by Charles Rino and published by John Wiley & Sons. This book was released on 2011-03-08 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to truly understand data signals transmitted by satellite, one must understand scintillation theory in addition to well established theories of EM wave propagation and scattering. Scintillation is a nuisance in satellite EM communications, but it has stimulated numerous theoretical developments with science applications. This book not only presents a thorough theoretical explanation of scintillation, but it also offers a complete library of MATLAB codes that will reproduce the book examples. The library includes GPS coordinate manipulations, satellite orbit prediction, and earth mean magnetic field computations. The subect matter is for EM researchers; however, also theory is relevant to geophysics, acoustics, optics and astoronomy.
Download or read book Radio Techniques for Probing the Terrestrial Ionosphere written by Robert D. Hunsucker and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the years since the pioneering efforts of Sir Edward Appleton, M. A. F. Barnett, G. Breit, and M. A. Thve, many radio techniques have been employed to investigate the terrestrial ionosphere. The purposes of this book are to exam ine the basic physical interaction process of radio waves with the ionosphere, scrutinize each of the radio techniques currently in use, and describe the elements of each technique, as well as assess their capabilities and limitations. I have included some of the history of each technique, since we often tend to forget the efforts of the "pioneers". The interaction of radio waves with the terrestrial ionosphere has been described in considerable detail in several "classic" treatments, e.g., Ratcliffe (1959), Al'pert (1963), Budden (1961) and Davies (1965), Rishbeth and e.g., Flock (1979), Davies Garriott (1969), and in other more recent books, (1990), Hargreaves (1979), and Budden (1985). A few of the radio techniques have been described by Hargreaves (1979) and a book by Giraud and Petit (1978) has also included discussion of several of the techniques. The "WITS" handbook No. 2 (1989) also contains description of several radio techniques.
Download or read book Ionospheric Scintillations TEC and In situ Density Measurements at an Auroral Location in the European Sector written by Eileen MacKenzie and published by . This book was released on 1987 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The orbiting HiLat satellite launched in 1983 offered an opportunity for studying ionospheric scintillation parameters in relation to in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. This report discusses results of a morphological study based on observations of scintillations and total electron content (TEC) at the auroral oval station at Tromso, Norway, during the period Dec 1983 - Oct 1985. The geometrical enhancement of scintillations observed during alignment of the propagation with the local magnetic L-shell is shown to be the most consistent and conspicuous feature of scintillations in the nighttime auroral oval. The dynamics of the spatial and temporal extent of this region are illustrated in the invariant latitude/magnetic local time grid. Steepening of phase spectral slope in the geometrical enhancement region is indicative of the presence of L-shell aligned sheet-like irregularities at long scale lengths. The seasonal variation of TEC determined from the differential Doppler measurements of HiLat transmissions is discussed in relation to the in-situ density measurements at 830 km. The results are also used to illustrate the dependence of ionospheric structure parameters on short-term variability of solar activity during the sunspot minimum period. This study provides an insight into the nature of magnetospheric coupling with the ionosphere at high latitudes.
Download or read book Climate Change in the Arctic written by Neloy Khare and published by CRC Press. This book was released on 2022-03-14 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Arctic, in the polar region, the northernmost part of Earth, is the hotspot for climate change assessments and the sensitive barometer of global climate variability. This book includes the scientific observations in the Arctic region’s climate and the results obtained by scientists at the Indian Arctic station Himadri over the past decade. Designed and structured to incorporate multi-dimensional climate change research output, it is a significant contribution toward understanding, among other issues, the role of persistent organic pollutants and mercury, as well as the increase of carbon monoxide during ozone reduction in the Arctic. Features include: Highlights the achievements of climate change research in the Arctic region Includes case studies of scientists in the Arctic and their significant achievements through the Indian research base Himadri Provides a thorough review of palaeoclimate change studies, the impact of climate change on biotic components and the impact of climate change on abiotic components Provides specific details on the study of ozone depletion phenomenon over the Arctic region Covers a wide range of research contributions Details sea ice variability in the context of global warming over the Arctic region Connects seismogenesis with the climate change in the Arctic region This book will be an important read for researchers, students and all interested professionals.
Download or read book Antarctic Upper Atmosphere written by Dr. Purushottam Bhawre and published by Notion Press. This book was released on 2020-08-14 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on the upper atmosphere of the Antarctica; it is not covering all upper atmospheric activity but gives basic ideas to understand the behavior of the Antarctic upper atmosphere and response during the short and long term variations, based on experimental data. This book describes the basics and History of Antarctica. Importance of Antarctic weather and how it plays a role in changing in global climate, e.g., Radiations, temperature, pressure. Upper Atmospheres of the Antarctic showing the basic structure of the upper atmosphere (ionosphere, Magnetosphere magnetic field lines) that is the main part of the research area and how the sun plays a role in changing space weather and atmospheric parameters. The response of the ionosphere layer, during space weather and its characterization over the High latitude region. This book will help other researchers for their future study on high latitude.
Download or read book Environmental Research Papers written by and published by . This book was released on 1971 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of the Ionosphere on Space Systems and Communications written by John M. Goodman and published by . This book was released on 1975 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compilation of Papers Presented by the Space Physics Division at the Ionospheric Effects Symposium IES 1978 written by U.S. Air Force Geophysics Laboratory and published by . This book was released on 1978 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a compilation of seventeen (17) papers presented by the Space Physics Division at the 1978 Symposium on the Effect of the Ionosphere on Space and Terrestrial Systems. The symposium was jointly sponsored by the Naval Research Laboratory and the Office of Naval Research, January 24-26, 1978. The emphasis is on the occurrence of ionospheric irregularities and their effect on communication, radar and navigation systems.
