Download or read book A Global Thermospheric Density Model Based on Satellite Accelerometer Data written by Frank A. Marcos and published by . This book was released on 1982 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Global Thermospheric Density Model Based on Satellite Accelerometer Data written by Frank A. Marcos and published by . This book was released on 1982 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements from the accelerometer experiments on four low-altitude satellites (S3-1 and Atmosphere Explorer-C, -D, and -E) have been combined to produce an empirical model of the neutral mass density from 140 to 240 km. Data from over a 8000 orbits are analyzed using the least-squares method of multiple linear regression. The resulting model gives density as a function of solar flux (for flux values 60 to 130 units), geomagnetic activity, day of year, local time, latitude and altitude. It provides a more accurate fit to the measured data than other available atmospheric models. Three commonly used models are evaluated by comparison of their predicted density variations with those of this empirical model. (Author).
Download or read book A Global Thermospheric Density Model Based on Satellite Accelerometer Data written by Frank A. Marcos and published by . This book was released on 1982 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements from the accelerometer experiments on four low-altitude satellites (S3-1 and Atmosphere Explorer-C, -D, and -E) have been combined to produce an empirical model of the neutral mass density from 140 to 240 km. Data from over a 8000 orbits are analyzed using the least-squares method of multiple linear regression. The resulting model gives density as a function of solar flux (for flux values 60 to 130 units), geomagnetic activity, day of year, local time, latitude and altitude. It provides a more accurate fit to the measured data than other available atmospheric models. Three commonly used models are evaluated by comparison of their predicted density variations with those of this empirical model.
Download or read book Variability of the Lower Thermosphere Determined from Satellite Accelerometer Data written by Frank A. Marcos and published by . This book was released on 1978 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive atmospheric density data base has been developed using accelerometer results from four low altitude satellites. The altitude range of the data is from 250 km down to as low as 140 km, with latitude coverage from 90 N to 90 S and local time periods that cover several 24-hr cycles. The data were obtained over a wide range of geomagnetic activity conditions. Solar radiation, as indicated by the 10.7-cm flux, was generally very low. Hence the data base applies mainly to solar minimum conditions. A description of the satellites, the accelerometer experiment, and the data base is given. Density variability is statistically analyzed in relation to selected atmospheric models. Particular attention is given to deviations from a normal distribution. Frequency distribitons of the data are described in terms of the mean value and the second, third, and fourth moments about the mean. This provides a more accurate description of extreme variations. The statistical properties of atmospheric variability are analyzed as a function of geomagnetic activity, latitude, altitude, and local time to develop a quantitative knowledge of unmodeled density variations. The results show that these accelerometer data will permit significant improvement in understanding the variations in the lower thermospheric density.
Download or read book Thermospheric Density and Wind Determination from Satellite Dynamics written by Eelco Doornbos and published by Springer Science & Business Media. This book was released on 2012-01-19 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Earth's atmosphere is often portrayed as a thin and finite blanket covering our planet, separate from the emptiness of outer space. In reality, the transition is gradual and a tiny fraction of the atmophere gases is still present at the altitude of low orbiting satellites. The very high velocities of these satellites ensure that their orbital motion can still be considerably affected by air density and wind. This influence can be measured using accelerometers and satellite tracking techniques. The opening chapters of this thesis provide an excellent introduction to the various disciplines that are involved in the interpretation of these observations: orbital mechanics, satellite aerodynamics and upper atmospheric physics. A subsequent chapter, at the heart of this work, covers advances in the algorithms used for processing satellite accelerometry and Two-Line Element (TLE) orbit data. The closing chapters provide an elaborate analysis of the resulting density and wind products, which are generating many opportunities for further research, to improve the modelling and understanding of the thermosphere system and its interactions with the lower atmosphere, the ionosphere-magnetosphere system and the Sun.
Download or read book Variability of the Lower Thermosphere Determined from Satellite Accelerometer Data written by Frank A. Marcos and published by . This book was released on 1978 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive atmospheric density data base has been developed using accelerometer results from four low altitude satellites. The altitude range of the data is from 250 km down to as low as 140 km, with latitude coverage from 90 N to 90 S and local time periods that cover several 24-hr cycles. The data were obtained over a wide range of geomagnetic activity conditions. Solar radiation, as indicated by the 10.7-cm flux, was generally very low. Hence the data base applies mainly to solar minimum conditions. A description of the satellites, the accelerometer experiment, and the data base is given. Density variability is statistically analyzed in relation to selected atmospheric models. Particular attention is given to deviations from a normal distribution. Frequency distribitons of the data are described in terms of the mean value and the second, third, and fourth moments about the mean. This provides a more accurate description of extreme variations. The statistical properties of atmospheric variability are analyzed as a function of geomagnetic activity, latitude, altitude, and local time to develop a quantitative knowledge of unmodeled density variations. The results show that these accelerometer data will permit significant improvement in understanding the variations in the lower thermospheric density.
Download or read book Wave Structures in Thermospheric Density from Satellite Electrostatic Triaxial Accelerometer Measurements written by Jeffrey M. Forbes and published by . This book was released on 1987 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density data from the Satellite Electrostatic Triaxial Accelerometer (SETA) experiment were spectrally analyzed by the Maximum Entropy Method (MEM). The purpose is to make available a technique by which the occurrence of wavelike structures in thermospheric densities can be quantitatively analyzed and correlated with various geophysical conditions, including the deposition of energy at high latitudes during geomagnetically disturbed conditions. Spectra were computed for typical magnetically quiet and active days during July 1983, and the relative occurrence of spectral peaks in wavelength ranges of large-scale (hundreds to thousands of kilometers) and medium-scale (tens to hundreds of kilometers) traveling ionospheric disturbances is examined as a function of local time and latitude.
Download or read book Global Density Specification in the Lower Thermosphere written by Jeffrey M. Forbes and published by . This book was released on 1988 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energetic inputs were derived from various satellite measurements and ground-based sensors for input into the Thermosphere General Circulation Model (TGCM) simulation of the magnetic storm occurring on March 22, 1979. The simulation was compared with thermospheric densities and winds measured from an Air Force satellite, and incoherent scatter radar measurements of thermospheric temperatures. An evaluation of the overall performance of the model and various physical processes accounting for discrepancies with data was performed. A FORTRAN program was developed to perform wave/spectral analyses of density data from the Satellite Electrostatic Triaxial Accelerometer (SETA) instrument using the maximum entropy method. The program was applied to a subset of available SETA data to illustrate typical wave characteristics for geomagnetically quiet and disturbed conditions. A climatological summary was performed of the average magnetic activity dependences of high-latitude thermospheric winds and densities below 200 km using SETA data from the March/April, 1979, period. Keywords: Density; Thermosphere; Winds; Waves; Magnetic activity. (JHD).
Download or read book Dynamics and Structure of the Quiet Thermosphere written by K. S. W. Champion and published by . This book was released on 1974 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The COSPAR International Reference Atmospheres (CIRA) 1972 provides both a Mean International Reference Atmosphere of the thermosphere and a parametric set of models for the region. The models are based on knowledge of the thermosphere as of mid 1971. The differences in the diurnal variations of atmospheric density scale height obtained from satellite drag studies and temperatures obtained from incoherent radar scatter observations are probably due to different diurnal variations of density and temperature and not due to systematic discrepancies in the measurements. The answer to this question should be provided by data obtained from recently launched satellites ESRO IV, AEROS, and AE-C. The second major area of interest involves the absolute number densities and variations with time of day, latitude, and season of the major and minor constituents of the thermosphere. Recent data obtained with mass spectrometers and optical instruments are reviewed in addition to the results of theoretical composition calculations, which include turbulence and other transport effects.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Space Weather written by Jean Lilensten and published by Springer Science & Business Media. This book was released on 2007-05-16 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book shows the state-of-the-art in Europe on a very new discipline, Space Weather. This discipline lies at the edge between science and industry. This book reflects such a position with theoretic papers and applicative papers as well. Each chapter starts with a short introduction, which shows the coherence of a given domain. Then, four to five contributions written by the best specialists in Europe give detailed hints of a hot topic in space weather.
Download or read book The Utility of Particle Precipitation Data as an Input to Thermospheric Density Models for Satellite Orbital Analysis written by Kelly Jon Hand and published by . This book was released on 1988 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this thesis is to determine the relative (compared to the Ap index) utility of global hemispheric power (PPE), as measured by the NOAA/TIROS satellite Total Energy Detector (TED) system, in describing magnetospherically induced upper thermospheric density perturbations. This was accomplished using satellite accelerometer, satellite orbital, Goettingen Ap, and PPE data from the geomagnetically active period of March 20th to April 10th, 1979. The first part of the study used Air Force Geophysics Laboratory (AFGL) satellite accelerometer thermospheric density data to determine the correlation between it and the PPE. This was then compared to the density data correlation with the Goettingen Ap. the data was scaled to optimize the meaning and linearity of the correlation coefficients and to emphasize any density fluctuations due to geomagnetic variations. The time series cross-correlation produced about a 6-hour lagged response in obtaining maximum correlation. (rh).
Download or read book 3S Technology Applications in Meteorology written by Shuanggen Jin and published by CRC Press. This book was released on 2023-10-19 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spatial information technology and its integration, such as remote sensing, geographic information systems (GIS), and global navigation satellite systems (GNSS), known as 3S technology, have been extensively utilized in managing and monitoring natural disasters. This book illustrates the 3S integrated applications in the field of meteorology and promotes the role of 3S in developing precise and intelligent meteorology. It presents the principles of 3S technology and the methods for monitoring different meteorological disasters and hazards as well as their application progress. The case studies from the United States, Japan, China, and Europe were conducted to help all countries understand the 3S technology functions in handling and monitoring severe meteorological hazards. FEATURES Presents integral observations from GNSS, GIS, and remote sensing in estimating and understanding meteorological changes Explains how to monitor and retrieve atmospheric parameter changes using GNSS and remote sensing Shows three-dimensional modelling and evaluations of meteorological variation processing based on GIS Helps meteorologists develop and use space-air-ground integrated observations for meteorological applications Illustrates the practices in monitoring meteorological hazards using space information techniques and case studies This book is intended for academics, researchers, and postgraduate students who specialize in geomatics, atmospheric science, and meteorology, as well as scientists who work in remote sensing and meteorology, and professionals who deal with meteorological hazards.
Download or read book Continuing Kepler s Quest written by National Research Council and published by National Academies Press. This book was released on 2012-10-06 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: In February 2009, the commercial communications satellite Iridium 33 collided with the Russian military communications satellite Cosmos 2251. The collision, which was not the first recorded between two satellites in orbit-but the most recent and alarming-produced thousands of pieces of debris, only a small percentage of which could be tracked by sensors located around the world. In early 2007, China tested a kinetic anti-satellite weapon against one of its own satellites, which also generated substantial amounts of space debris. These collisions highlighted the importance of maintaining accurate knowledge, and the associated uncertainty, of the orbit of each object in space. These data are needed to predict close approaches of space objects and to compute the probability of collision so that owners/operators can decide whether or not to make a collision avoidance maneuver by a spacecraft with such capability. The space object catalog currently contains more than 20,000 objects, and when the planned space fence radar becomes operational this number is expected to exceed 100,000. A key task is to determine if objects might come closer to each other, an event known as "conjunction," and the probability that they might collide. The U.S. Air Force is the primary U.S. government organization tasked with maintaining the space object catalog and data on all space objects. This is a complicated task, involving collecting data from a multitude of different sensors-many of which were not specifically designed to track orbiting objects-and fusing the tracking data along with other data, such as data from atmospheric models, to provide predictions of where objects will be in the future. The Committee for the Assessment of the U.S. Air Force's Astrodynamic Standards collected data and heard from numerous people involved in developing and maintaining the current astrodynamics standards for the Air Force Space Command (AFSPC), as well as representatives of the user community, such as NASA and commercial satellite owners and operators. Preventing collisions of space objects, regardless of their ownership, is in the national security interested of the United States. Continuing Kepler's Quest makes recommendations to the AFSPC in order for it to create and expand research programs, design and develop hardware and software, as well as determine which organizations to work with to achieve its goals.
Download or read book Geometrical Theory of Satellite Orbits and Gravity Field written by Drazen Svehla and published by Springer. This book was released on 2018-07-02 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book on space geodesy presents pioneering geometrical approaches in the modelling of satellite orbits and gravity field of the Earth, based on the gravity field missions CHAMP, GRACE and GOCE in the LEO orbit. Geometrical approach is also extended to precise positioning in space using multi-GNSS constellations and space geodesy techniques in the realization of the terrestrial and celestial reference frame of the Earth. This book addresses major new developments that were taking place in space geodesy in the last decade, namely the availability of GPS receivers onboard LEO satellites, the multitude of the new GNSS satellite navigation systems, the huge improvement in the accuracy of satellite clocks and the revolution in the determination of the Earth's gravity field with dedicated satellite missions.
Download or read book Modeling the Ionosphere Thermosphere written by J. D. Huba and published by John Wiley & Sons. This book was released on 2014-03-17 with total page 735 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 201. Modeling the Ionosphere-Thermosphere System brings together for the first time a detailed description of the physics of the IT system in conjunction with numerical techniques to solve the complex system of equations that describe the system, as well as issues of current interest. Volume highlights include discussions of: Physics of the ionosphere and thermosphere IT system, and the numerical methods to solve the basic equations of the IT system The physics and numerical methods to determine the global electrodynamics of the IT system The response of the IT system to forcings from below (i.e., the lower atmosphere) and from above (i.e., the magnetosphere) The physics and numerical methods to model ionospheric irregularities Data assimilation techniques, comparison of model results to data, climate variability studies, and applications to space weather Providing a clear description of the physics of this system in several tutorial-like articles, Modeling the Ionosphere-Thermosphere System is of value to the upper atmosphere science community in general. Chapters describing details of the numerical methods used to solve the equations that describe the IT system make the volume useful to both active researchers in the field and students.
Download or read book International Symposium on Advancing Geodesy in a Changing World written by Jeffrey T. Freymueller and published by Springer. This book was released on 2019-03-12 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings contain 23 papers, which are the peer-reviewed versions of presentations made at the Joint Scientific Assembly of the International Association of Geodesy (IAG) and the International Association of Seismology and Physics of the Earth’s Interior (IASPEI). The assembly was held from 30 July to 4 August 2017 in Kobe, Japan. The scientific assembly included seven symposia organized by IAG, and nine joint symposia, along with additional symposia organized by IASPEI. The IAG symposia were structured according to the four IAG Commissions and the three GGOS Focus Areas, and included reference frames, static and time-variable gravity field, Earth rotation and geodynamics, multi-signal positioning, geodetic remote sensing, and GGOS. The joint symposia included monitoring of the cryosphere, studies of earthquakes, earthquake source processes, and other types of fault slip, geohazard warning systems, deformation of the lithosphere, and seafloor geodesy. Together, the IAG and joint symposia spanned a broad range of work in geodesy and its applications.
