Download or read book Theory and Analysis of Meteor Head Echoes and Meteoroids Using High resolution Multi frequency Radar Data written by Sigrid Close and published by . This book was released on 2004 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modern Meteor Science written by Robert Hawkes and published by Springer Science & Business Media. This book was released on 2006-08-18 with total page 707 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains leading edge research and authoritative reviews in meteor science. It provides a comprehensive view of meteoroid research including the dynamics, sources and distribution of these bodies. Techniques for investigation of meteor phenomena in the book include conventional and large aperture radar systems, spacecraft detection, optical systems, spectral measurements, and laboratory based interplanetary dust particle studies.

Download or read book Advances in Meteoroid and Meteor Science written by J.M. Trigo-Rodriguez and published by Springer Science & Business Media. This book was released on 2008-03-21 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: This rigorously refereed volume is a compilation of articles that summarize the most recent results in meteor, meteoroid and related fields presented at the Meteoroids 2007 conference held at the impressive CosmoCaixa Science Museum in Barcelona, Spain.

Download or read book Meteoroid Mass from Head Echoes Using Particle in cell and Finite difference Time domain Simulations written by Glenn Flinn Sugar and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing accessibility of space has enabled new technologies that have significantly affected our society. These technologies rely on spacecraft that must operate in the space environment, a domain that presents unique risks and dangers. Therefore, there is a significant motivation to understand the dangers of the space environment, one of which are meteoroids, defined by the International Astronomical Union as ``a solid natural object of a size roughly between 30 micrometers and 1 meter moving in, or coming from, interplanetary space." Spacecraft-meteoroid collisions are high energy and potentially destructive events due to the high meteoroid velocities relative to Earth that range from 11.2-72.8 km/s. Studies have shown that every square meter of exposed spacecraft surface area experiences a meteoroid impact that causes a crater with a diameter $> 40$ micrometers approximately once a day. The increasing reliance on spacecraft motivates a better understanding of the threats that meteoroids present, but estimates of the meteoroid mass distribution have orders of magnitude differences due to large uncertainties in meteoroid mass models. One method of calculating meteoroid mass uses radar reflections of the plasma surrounding an ablating meteoroid, otherwise known as meteor head echoes. High-Power Large-Aperture (HPLA) radars can detect approximately one head echo per second, enabling the collection of vast data sets of meteors and a better understanding of the meteoroid mass distribution. However, current methods used to calculate meteoroid masses from head echoes contain large uncertainties and result in distributions that are orders of magnitude different from distributions derived using other methods, such as crater analysis of spacecraft and optical observations. This thesis presents and validates a method to estimate meteoroid masses from head echo observations. First, the plasma distribution around an ablating meteoroid with Particle-In-Cell (PIC) simulations are calculated and the effects of parameters such as the Earth's magnetic field on the distribution are explored. Also, the PIC derived plasma distributions are compared to a simplified analytical model based on kinetic theory that neglects electric and magnetic fields. Second, The radar cross section (RCS) of various meteor head plasma density distributions are calculated with Finite-Difference Time-Domain (FDTD) electromagnetic simulations. The simulation results are then used to develop a new model to map a head echo radar observation to a meteoroid mass. This new model is validated with head echo radar observations from the Canadian Meteor Orbit Radar (CMOR), and analysis shows that it outperforms previously used models used for head echo derived meteoroid mass estimation.

Download or read book IRF Scientific Report written by and published by . This book was released on 2008 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Determining Meteoroid Properties Using Head Echo Observations from the Jicamarca Radio Observatory written by Elizabeth N. Fucetola and published by . This book was released on 2012 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Over 100 tons of material enters the Earth's atmosphere every day, mostly in the form of meteoroids less than a millimeter across. As a meteoroid enters the atmosphere, it ablates and forms a plasma. Radars can detect this plasma, which travels at approximately the same speed as the meteoroid, as a head echo. Such observations can determine the speed and trajectory of a meteoroid with high accuracy. A better characterization of these small particles will contribute to our understanding of the Earth's atmosphere, the solar system, and the local interstellar medium. Meteoroids provide a source of heavy metals at high altitudes that impact atmospheric chemistry and physics. Greater knowledge of the composition and masses of meteoroids will help astronomers understand the material within the solar system and the local interstellar medium. This dissertation focuses on meteoroid head echo observations using the 50 MHz radar at the Jicamarca Radio Observatory. These provide high resolution observations in both range and time. We use this data to evaluate methods of determining meteoroid properties and introduce a technique to determine meteoroid mass which involves fitting range and velocity measurements to an ablation model. This technique is compared with some established mass estimation methods, including scattering mass theory. We find the overall mass distribution for observed meteoroids as well as the spatial distribution of these particles. The peak of our mass distribution, at approximately 10 -11 kg, is significantly lower than what is found using specular meteor radars. We illustrate how the spatial distribution varies with meteoroid mass, and how different meteoroid sources appear when different mass ranges are examined. For the smallest meteoroids, only the Apex sources are detected, while all six of the dominant meteor sources are observed with comparable intensity when examining meteors with a mass larger than 10 -9 kg. We also directly compare meteor data taken with the 50 MHz radar to observations using a specular meteor radar in a novel experiment using both instruments simultaneously.

Download or read book Annales Geophysicae written by and published by . This book was released on 2009 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Resolution VHF Meteor Study written by Stanford University. Stanford Electronics Laboratories and published by . This book was released on 1966 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: High resolution, dual-frequency, VHF observations of meteors were conducted during 1964 and 1965 utilizing the DAZZLE radar at Central Bore, South Australia. An abridged description of the radar as it applies to these observations is given and full operational and data reduction procedures are discussed. Development of a fully automatic film reading program was undertaken and is also described. The data taken on three meteors at 55 MHz is discussed with emphasis given to trail echo characteristics as observed using short (0.5 microsec) pulses. An unexpected new phenomenon--long period (approximately 200 ms) cross-section variations--was discovered. Further work on the data including analysis of coherent phase returns is also discussed. (Author).

Download or read book Meteoroids written by Galina O. Ryabova and published by Cambridge University Press. This book was released on 2019-10-10 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive guide to modern meteor science, destined to be the standard resource for advanced students and researchers.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel High altitude Meteor Observing Strategies Employed at the Jicamarca Radio Observatory written by Boyi Gao and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most controversial arguments within the radar meteor community is whether meteor head echoes above the traditional meteor zone (70~130 km above the Earth surface) can be observed by radars or not. Classical ablation theory, which assumes intensive evaporation following a temperature rise up to about 2000K, does not explain meteoroid-produced ionization at high altitudes where the atmosphere is rather thin. The mechanism for ionization at high-altitudes still remains an open question.When it comes to high-altitude radar meteors (HARMs) experiment, there are three types of ambiguity issues: range ambiguity, Doppler speed ambiguity, and angle-of-arrival ambiguity. Range and Doppler speed ambiguities are related to the length of Inter-Pulse-Period (IPP), but interconnected. Range ambiguity is proportional to the length of IPP. In order to increase the unambiguous range, the length of IPP must be increased. Doppler speed ambiguity, however, is inversely proportional to the length of IPP. Consequently, a tradeoff must be made between range and Doppler speed ambiguities in terms of choosing the length of IPP. A new technique employed in this HARM observation experimentAlternating Inter-Pulse-Periods (AIPPs)enables us the resolve these two problems at the same time, without compromising one or the other. Additionally, for radar system with interferometric baselines larger than half of its operating wavelength, such as at Jicamarca Radio Observatory (JRO), angle-of-arrival ambiguity is introduced in the determination of angular positions of detected targets. Therefore, high-altitude radar meteors are usually interpreted as sidelobe contaminations with large ranges but lower altitudes. A new unambiguous, multi-baseline interferometric technique was recently employed for meteor observations at JRO for the first time. It yielded the true angle-of-arrival of HARM events. All these advanced techniques facilitate more accurate data interpretation and better understanding of the physics behind meteor-related phenomena. The data presented herein are collected from August 4/5, 2014 experiment utilizing novel observing strategies to confirm the existence of high altitude radar meteors. In these observations a sequence of four alternating IPPs, 1723 s, 1733 s, 1747 s, and 1759 s, was used. The AIPP technique unambiguously recovered the instantaneous Doppler speeds of fast-moving meteor head echoes. The radar transmission was from two quarter-arrays sharing a common diagonal in the East-West direction. Signal reception was via three, quarter-array (Q) receivers and three adjacent (M) module receivers all of the same polarization. One extra quarter-array receiver of perpendicular polarization was also employed to monitor crosstalk. This arrangement offered the usual Q-Q and M-M interferometric baseline-pairs as well as new Q-M baselines that were rotated ~6 from the Q-Q and M-M baselines. For relatively high signal-to-noise ratio (SNR) meteors, this new radar configuration yields ambiguity resolution to the horizon and confirms the existence of HARM events.

Download or read book Meteor Science and Engineering written by Donald William Robert McKinley and published by New York ; Toronto : McGraw-Hill. This book was released on 1961 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Meteor Head Echo Signatures at Polar Latitudes written by Carsten Schult and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Extraterrestrial particles entering the Earth's atmosphere with a sufficient amount of kinetic energy can be observed as meteors in a clear night or as meteor echoes by using radar observations. High power large aperture (HPLA) radars are able to detect the small plasma cloud that is formed around the meteoroid during the ablation process, which is called meteor head echo. In contrast to optical meteor observations, radar systems can measure independent of weather conditions as well as during day and night.eng

Download or read book Investigation of Meteors and Their Impact on the Sodium Layer in the Mesosphere and Lower Thermosphere written by Yanlin Li and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Meteoroids are small interplanetary and interstellar particles that enter Earth's atmosphere and ablate. The observable phenomena associated with meteoroid ablation are commonly referred to as meteors. The plasma surrounding the meteoroid, or the ionized trail left behind by the meteoroid, can be detected by radar. By analyzing the physical characteristics of these meteors, such as their size and velocity, researchers can gain insights into the composition and distribution of meteoroids in our solar system. Radar detection is a valuable tool for studying meteoroids as it provides a relatively low-cost, non-intrusive, and high-resolution method for detecting these elusive objects. This dissertation introduces three radar meteor detection algorithms. The newly developed detection algorithms and signal processing workflows represent a significant advancement compared to existing approaches, demonstrating superior sensitivity and/or automation levels. These innovative methods constitute a substantial improvement in the field, promising to enhance the quality and accuracy of meteor detection and analysis. The first algorithm, the Statistical-based Head Echo Detection algorithm (SHED), employs a probabilistic model utilizing coded long pulse and meticulously defined probabilities to distinguish meteor echoes from noise. The second algorithm, known as AHEAD, is a sensitivity-prioritized method that can detect more than 200 meteors per minute from data obtained from the Jicamarca incoherent scatter radar. The third algorithm presented in this dissertation, MADAME, incorporates state-of-the-art machine-learning computer vision techniques into radar digital signal processing. By utilizing a variety of deep learning architectures, including both supervised and unsupervised learning, MADAME offers a fast yet effective approach to meteor echo detection and analysis. Both AHEAD and MADAME algorithms are capable of performing interferometric analysis on meteor echoes. Notably, AHEAD's variant workflow can resolve interferometric aliasing, resulting in a more accurate determination of the vector direction and speed of the meteors. Overall, these three cutting-edge algorithms demonstrate significant potential in enhancing the accuracy and precision of meteor detection and analysis. Furthermore, this dissertation presents the first sporadic micro-meteor radiant source distribution derived from the observations conducted at the Arecibo Observatory. The findings unveil all six sporadic meteor radiant sources, namely North and South Apex (NA and SA), North and South Toroidal (NT and ST), and Helion and Anti-Helion sources (H and AH). Moreover, this research investigates the impact probability among various orbits. Meteoroids are generally acknowledged as the source of the metal layers in the Earth's upper atmosphere. Meteoroid material input can impact various atmospheric processes and contribute to our comprehension of the physical processes that occur in the upper atmosphere. Sodium is one of the species of the atmospheric metal layer. In this dissertation, we present a new numerical sodium chemistry model, referred to as NaChem, that treats all involved species with continuity equations instead of using the steady-state approximation. The study aims to investigate the relationship between the global meteoroid material input and the seasonal variation of the sodium layers in the MLT by comparing simulation and observational data. The simulation incorporates components of the Whole Atmosphere Community Climate Model (WACCM) for background gas species. Our findings are consistent with the general features of the measurements obtained from the Colorado State University Lidar (CSU) and the Andes Lidar Observatory (ALO). Overall, this dissertation contributes to our understanding of meteor detection, the distribution of their radiant sources, and their impact on the atmospheric sodium layer in the MLT.

Download or read book Meteoroids written by Galina O. Ryabova and published by Cambridge University Press. This book was released on 2019-10-10 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: This definitive guide provides advanced students and researchers with a detailed yet accessible overview of all of the central topics of meteor science. Leading figures from the field summarise their active research on themes ranging from the physical composition of meteoroids to the most recent optical and radar observations and ongoing theoretical developments. Crucial practical issues are also considered, such as the risk posed by meteoroids - to spacecraft, and on the ground - and future avenues of research are explored. Taking advantage of the latest dynamical models, insights are offered into meteor flight phenomena and the evolution of meteoroid streams and complexes, as well as describing the in-depth laboratory analysis of recovered material. The rapid rate of progress in twenty-first-century research makes this volume essential reading for anyone who wishes to understand how recent developments broaden our understanding of meteors, meteoroids and their origins.

Download or read book Radar Meteor Trail Task written by Arnold A. Barnes and published by . This book was released on 1972 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced, inexpensive, transportable radar meteor trail set was developed and was recommended as an international standard by IUCSTP at the Moscow 1971 COSPAR meeting. The interferometer height-measuring technique, tested with the CRLH 001 Beacon in satellite OV1-17, was also recommended because of ground calibration capability and achieved accuracy. Computer programs for data reduction and advanced analysis were used to reduce and study wind and density data from AFCRL, Eglin AFB, Stanford University and the University of New Hampshire. Results were compared with other investigators' findings. (Author).

Download or read book Radar Observations of Meteors According to the International Geophysical Year Program written by Boris Leonidovich Kashcheev and published by . This book was released on 1961 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: