Download or read book Inversion of Arecibo Long pulse Incoherent Scatter Radar Data written by Kaushik Roy and published by . This book was released on 2003 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Near optimal Inversion of Incoherent Scatter Radar Measurements Coding Schemes Processing Techniques and Experiments written by Romina Nikoukar and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate and efficient estimation of the key ionospheric state parameters such as electron density, ion composition, and electron and ion temperatures is required to understand fundamental issues of terrestrial plasma physics such as redistribution of energy and momentum, and coupling within terrestrial upper atmosphere regions. This work focuses on developing a modern coding scheme and inversion methodology using Arecibo incoherent scatter radar (ISR) to achieve efficient, and near-optimal estimates of the key ionospheric parameters. In particular, this work considers two aspects of the ISR inversion problem: (i) ISR lag estimates at individual altitudes, and (ii) modulation techniques that can provide more accurate estimates with a specific range resolution. These two aspects suggest a unifying framework for ISR inversion in which modern computational technology and ISR methodology are utilized in a robust estimation procedure. The first contribution of this work is the development of a discrete forward model for F-region incoherent scatter measurements, where long pulses are utilized in transmission. The range smearing imposed on measurements by long pulses is modeled as a one-dimensional convolution along the range in the simplified case where the receiver sampling is instantaneous. The next major phase of this research is to develop an efficient hybrid technique that allows for estimation of plasma parameters by removing range smearing from measurements. The inversion technique incorporates both quadratic and edge-preserving regularization approaches in order to provide smooth plasma auto-correlation function (ACF) lag profiles in the presence of noise while still resolving the sharp gradients. Another contribution of this thesis is to develop a technique for optimal modulation design in ISR experiments. The optimal resolution supported by ISR measurements is used as one criterion for the optimal design. The model order selection framework is applied to the problem at hand to find the optimal resolution. The results indicate that, compared with a long pulse, amplitude-modulated codes yield finer range resolutions with nearly similar parameter estimation errors or smaller estimation errors with the same range resolution. In medium to high SNR scenarios, a smaller on-off ratio of the transmitted waveform is recognized as a determining factor for allowing more freedom in removing range ambiguities as well as resulting in improved statistical accuracy for integrated data in range and lag directions. In order to find the optimal amplitude modulation for Arecibo ISR measurements in medium to high SNR scenarios, a modified form of the sequential backward selection algorithm is applied to the space of all amplitude modulated pulses with a certain on-off ratio. Due to the vast search space, there is no possibility for an exhaustive search. Therefore, the problem of finding the optimal amplitude modulation is viewed as an optimization problem. Three optimality criteria, namely, sum of squared errors, uniformity of estimation errors, and condition number of convolution matrices, are considered. The final contribution of this work was implementing and conducting several experiments in April 2004, August 2005, and July 2006 using the incoherent scatter radar at Arecibo Observatory, and applying the inversion technique to estimate the plasma parameters. In these experiments, the original mode of MRACF was modified to utilize amplitude modulation. The results of all these experiments verify that when the SNR is sufficiently high, compared with an unmodulated long pulse, improved range resolution with nearly the same statistical accuracy is obtained when an amplitude modulation is utilized. The results of the developed methodology and experimental design of this work can be extended to other incoherent scatter radars (such as Jicamarca radar in Peru, and advanced modular incoherent scatter radar in Alaska) to improve the estimation task in other altitude and latitude regions, and to extract many further ionospheric parameters such as electric field strength, conductivity, current, and neutral wind speed.

Download or read book Chirped Incoherent Scatter Radar Observations of the HF modified Ionosphere written by Brett Cameron Isham and published by . This book was released on 1991 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Antennas and Radar for Environmental Scientists and Engineers written by David Hysell and published by Cambridge University Press. This book was released on 2018-03 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive, self-contained book covers everything needed to understand how radar signals are used to study Earth's environment.

Download or read book Annales Geophysicae written by and published by . This book was released on 2008 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Intense Spreading of Radar Echoes from Ionospheric Plasmas written by Seth E. Dorfman and published by . This book was released on 2005 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: On December 25, 2004, a large-scale ionospheric plasma bubble was observed over Arecibo Observatory in Puerto Rico, inducing significant range spreading on ionograms. This phenomena may be explained by means of the E x B instability and gravitational Rayleigh-Taylor instability. A derivation of the dispersion relations for X and O mode waves transmitted from an ionosonde and an analysis of the collisional Rayleigh-Taylor instability leading to an expression for the growth rate are presented as background information. Ray tracing code developed by Nathan Dalrymple, a previous graduate student of Professor Min-Chang Lee, is extended, first to draw refractive index surfaces to illustrate a key principle in ray tracing and later to simulate range spreading due to depleted ionospheric ducts [1]. Data from Arecibo incoherent scatter radar and Arecibo's CADI digisonde is examined showing strong evidence for the development of a plasma bubble following a rise in the plasma layer and the appearance of a horizontal density gradient. In one portion of the ionosphere, this gradient is found to be at an angle of approximately 70 degrees to the Earth's magnetic field, a favorable condition for the excitation of the Rayleigh-Taylor instability over Arecibo.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Upper Atmospheres of the Earth and Planets written by Charles Adolph Barth and published by . This book was released on 1983 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Doppler Radar Observations written by Joan Bech and published by BoD – Books on Demand. This book was released on 2012-04-05 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doppler radar systems have been instrumental to improve our understanding and monitoring capabilities of phenomena taking place in the low, middle, and upper atmosphere. Weather radars, wind profilers, and incoherent and coherent scatter radars implementing Doppler techniques are now used routinely both in research and operational applications by scientists and practitioners. This book brings together a collection of eighteen essays by international leading authors devoted to different applications of ground based Doppler radars. Topics covered include, among others, severe weather surveillance, precipitation estimation and nowcasting, wind and turbulence retrievals, ionospheric radar and volcanological applications of Doppler radar. The book is ideally suited for graduate students looking for an introduction to the field or professionals intending to refresh or update their knowledge on Doppler radar applications.

Download or read book Middle Atmosphere Program Papers presented at the URSI written by and published by . This book was released on 1981 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Radio Science written by and published by . This book was released on 2008 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Middle Atmosphere Program written by and published by . This book was released on 1981 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AN INVERSION TECHNIQUE TO RECOVER LOWER THERMOSPHERIC WINDS FROM SPACE BORNE REMOTE MEASUREMENTS OF OI 5577 ANGSTROMS THERMOSPHERE WINDS written by Bruno Nardi and published by . This book was released on 1991 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: incoherent scatter radar at the Sondre Stromfjord, Greenland facility. It was found that the ideal geophysical conditions required by the two instruments were almost mutually exclusive for this particular measurement. The necessary conditions for making simultaneous measurements were identified and confirmed by obtaining several hours of observations during a period exhibiting such conditions.

Download or read book Meteorological and Geoastrophysical Abstracts written by and published by . This book was released on 1996 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Papers on Laser Applications in Remote Sensing written by William B. Grant and published by SPIE-International Society for Optical Engineering. This book was released on 1997 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text explores the field of laser applications in remote sensing.