Download or read book Radar Observations and Numerical Modeling of Bottomside Equatorial Spread F written by Joseph Patrick Flaherty and published by . This book was released on 1997 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulations and Observations of Equatorial F Region Plasma Irregularities written by Henrique Carlotto Aveiro and published by . This book was released on 2012 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes a theoretical, experimental, and modeling investigation of the plasma irregularities in equatorial spread F (ESF). The primary scientific objective is to evaluate the electrodynamic nature of equatorial F region plasma instabilities. In particular, the difference between two-dimensional and three-dimensional electrodynamic effects on the onset and evolution of equatorial instabilities is investigated. Statistical studies are performed using the Jicamarca Unattended Long Term Investigations of the Ionosphere and Atmosphere (JULIA) radar at Jicamarca. The climatology, persistence, and the correlation with the phase of the moon of equatorial spread F irregularities are evaluated, and different forecasting tools are compared. A three dimensional electrostatic numerical model of the equatorial ionosphere using a finite volume method transport scheme is described. The model incorporates realistic ionospheric conductivities, electric fields, and winds. The model is capable of reproducing the full complement of relevant equatorial F region ionospheric plasma instabilities under realistic conditions, including bottomside shear flow. Of chief importance is the so-called "collisional shear instability" which has come to light recently as a potentially important mechanism in the initiation of ESF. This instability has a faster growth rate than the conventional generalized Rayleigh Taylor (gRT) instability under typical post-sunset conditions. The combination of gRT and CSI produces an instability which develops into an intense ESF event more quickly and with more realistic characteristics than the other two independently in simulations. The model is initialized with data acquired by the C/NOFS satellite, the Jicamarca Radio Observatory, ALTAIR radar, and other ground-based instruments. The forecast potential of the simulation is evaluated through a number of "after the fact" case studies. Various diagnostic codes are used to validate the simulations. To compute the magnetic induction due to ionospheric currents, for example, we solve the partial differencial equation resulting from the Ampère's law for magnetostatics. Airglow emissions corresponding to the sime ulation runs are likewise computed for the 6300-Å (or oxygen red) line. Simulated airglow images are obtained through the integration of the volume emission rates along the camera line of sight. Coherent/incoherent scatter simulations corresponding to the model runs show the typical three stages of ESF evolution, from bottom-type to bottomside to topside ESF. Some of the features that the simulated electron density maps share with ALTAIR scans include westward tilted ascending depletions connected to the bottomside, periodic spacing of 100-200 km in the zonal direction, bifurcation, secondary instabilities growing on the western walls of the primaries, and rates of development. The main goal of these studies has been both to verify the efficacy of the simulation code and its forecast potential while also placing these common but ambiguous diagnostic methods in a formal theoretical/modeling context for the first time.
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 Investigation of Persistence Model for Radar Plume Occurrence Using the JULIA Radar and Examination of Shear Instability in Equatorial Spread F written by Yann Fang Lee and published by . This book was released on 2004 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ionosphere and Applied Aspects of Radio Communication and Radar written by Nathan Blaunstein and published by CRC Press. This book was released on 2008-05-13 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Complete Reference for the 21st Century Until recently, much of the communications technology in the former Eastern bloc countries was largely unknown. Due to the historically competitive nature of East/West relations, scientific groups operated independently, without the benefit of open communication on theoretical framework
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1982 with total page 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 Nonlinear Equatorial Spread F Dependence on Altitude of the F Peak and Bottomside Background Electron Density Gradient Scale Length written by S. L. Ossakow and published by . This book was released on 1978 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four different two dimensional (perpendicular to the ambient magnetic field), plasma fluid-type, numerical simulations following the nonlinear evolution of the collisional Rayleigh-Taylor instability in the nighttime equatorial F region ionosphere have been performed. Realistic altitude dependent ion-neutral collision frequencies, recombination rates, and ambient electron density profiles were used. In three cases (ESF 0, 1, 3) the electron density profile was kept constant, with a minimum bottomside background electron density gradient scale length L about 10 km, but the altitude of the F peak was changed, with F peak altitudes at 340, 350, and 430 km. All cases resulted in bottomside growth of the instability (Spread F) with dramatically different time scales for development. Plasma density depletions were produced on the bottomside with rise velocities, produced by nonlinear polarization E x B forces, of 2.5, 12, and 160 m/sec, and percentage depletions of 16, 40, and 85, respectively. High altitude of the F peak, small bottomside electron density gradient scale lengths, and large percentage depletions yield large vertical bubble rise velocities, with the first two conditions favoring bottomside linear growth of the instability. The numerical simulation results are in good agreement with rocket and satellite in situ measurements and radar backscatter measurements, including some of the recent results from the August 1977 coordinated ground based measurement campaign conducted by DNA at Kwajalein.
Download or read book National Space Weather Program written by and published by . This book was released on 2000 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Earth Observation with CHAMP written by Christoph Reigber and published by Springer Science & Business Media. This book was released on 2005 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the summer of 2000 the German geo-research satellite CHAMP was launched into orbit. Its innovative payload arrangement and the low initial orbit allow CHAMP to simultaneously collect and almost continuously analyse precise data relating to gravity and magnetic fields at low altitude. In addition, CHAMP also measures the neutral atmosphere and ionosphere using GPS techniques. Three years after launch, more than 200 CHAMP investigators and co-investigators from all over the world met at the GeoForschungsZentrum in Potsdam to present and discuss the results derived from the extensive data sets of the mission. The main outcome of this expert meeting is summarized in this volume. The book offers a comprehensive insight into the present status of the exploitation of CHAMP data for Earth system research and practical applications in geodesy, geophysics and meteorology.
Download or read book Dynamics of Equatorial Spread F Using Ground based Optical and Radar Measurements written by Narayan P. Chapagain and published by . This book was released on 2011 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Earth's equatorial ionosphere most often shows the occurrence of large plasma density and velocity fluctuations with a broad range of scale sizes and amplitudes. These night time ionospheric irregularities in the F-region are commonly referred to as equatorial spread F (ESF) or plasma bubbles (EPBs). This dissertation focuses on analysis of ground-based optical and radar measurements to investigate the development and dynamics of ESF, which can significantly disrupt radio communication and GPS navigation systems. OI (630.0 nm) airglow image data were obtained by the Utah State University all-sky CCD camera, primarily during the equinox period, from three different longitudinal sectors under similar solar flux conditions: Christmas Island in the Central Pacific Ocean, Ascension Island in South Atlantic, and Brasilia and Cariri in Brazil. Well-defined magnetic field-aligned depletions were observed from each of these sites enabling detailed measurements of their morphology and dynamics. These data have also been used to investigate day-to-day and longitudinal variations in the evolution and distribution of the plasma bubbles, and their nocturnal zonal drift velocities. In particular, comparative optical measurements at different longitudinal sectors illustrated interesting findings. During the post midnight period, the data from Christmas Island consistently showed nearly constant eastward bubble velocity at a much higher value (~80 m/s) than expected, while data from Ascension Island exhibited a most unusual shear motion of the bubble structure, up to 55 m/s, on one occasion with westward drift at low latitude and eastward at higher latitudes, evident within the field of view of the camera. In addition, long-term radar observations during 1996-2006 from Jicamarca, Peru have been used to study the climatology of post-sunset ESF irregularities. Results showed that the spread F onset times did not change much with solar flux and that their onset heights increased linearly from solar minimum to solar maximum. On average, radar plume onset occurred earlier with increasing solar flux, and plume onset and peak altitudes increased with solar activity. The F-region upward drift velocities that precede spread F onset increased from solar minimum to solar maximum, and were approximately proportional to the maximum prereversal drift peak velocities.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vertical Coupling in the Atmosphere Ionosphere Magnetosphere System written by Jaroslav Chum and published by Frontiers Media SA. This book was released on 2024-01-30 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spring Meeting written by American Geophysical Union. Meeting and published by . This book was released on 2001 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronomy of the Earth s Atmosphere and Ionosphere written by Mangalathayil Ali Abdu and published by Springer Science & Business Media. This book was released on 2011-02-26 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a multi-author treatise on the most outstanding research problems in the field of the aeronomy of the Earth’s atmosphere and ionosphere, encompassing the science covered by Division II of the International Association of Geomagnetism and Aeronomy (IAGA). It contains several review articles and detailed papers by leading scientists in the field. The book is organized in five parts: 1) Mesosphere-Lower Thermosphere Dynamics and Chemistry; 2) Vertical Coupling by Upward Propagating Waves; 3) Ionospheric Electrodynamics and Structuring; 4) Thermosphere- Ionosphere Coupling, Dynamics and Trends and 5) Ionosphere-Thermosphere Disturbances and Modeling. The book consolidates the progress achieved in the field in recent years and it serves as a useful reference for graduate students as well as experienced researchers.
Download or read book Report of NRL Progress written by Naval Research Laboratory (U.S.) and published by . This book was released on with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
