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Simultaneous Radar and Video Meteors Western University Scholarship@Western Electronic Thesis and Dissertation Repository 12-10-2012 12:00 AM Simultaneous radar and video meteors Robert J. Weryk The University of Western Ontario Supervisor Peter Brown The University of Western Ontario Graduate Program in Physics A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © Robert J. Weryk 2012 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Other Physics Commons Recommended Citation Weryk, Robert J., "Simultaneous radar and video meteors" (2012). Electronic Thesis and Dissertation Repository. 1021. https://ir.lib.uwo.ca/etd/1021 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact [email protected]. SIMULTANEOUS RADAR AND VIDEO METEORS (Thesis format: Integrated Article) by Robert Weryk Graduate Program in Physics A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy The School of Graduate and Postdoctoral Studies The University of Western Ontario London, Ontario, Canada c Robert Joseph Weryk 2012 THE UNIVERSITY OF WESTERN ONTARIO School of Graduate and Postdoctoral Studies CERTIFICATE OF EXAMINATION Examiners: Supervisor: .............................. .............................. Dr. Jirˇ´ı Borovickaˇ Dr. Peter Brown Supervisory Committee: .............................. Dr. Sarah Gallagher .............................. Dr. Martin Houde .............................. Dr. Wayne Hocking .............................. Dr. Robert Sica .............................. Dr. Kristy Tiampo The thesis by Robert Joseph Weryk entitled: Simultaneous radar and video meteors is accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy ..................... ....................................... Date Chair of the Thesis Examination Board ii Abstract The goal of this thesis is to better understand the physical and chemical properties of mete- oroids by using simultaneous radar and video observations of meteors. The Canadian Meteor Orbit Radar (CMOR) and several Gen-III image-intensified CCD cameras were used to mea- sure common meteors and validate metric errors determined through Monte Carlo modelling and to relate radar electron line density (q) to video photon radiant power (I). By adopt- ing an ionisation coefficient from Jones (1997) and using recorded measurements of q=I, a corresponding estimate of the fraction of meteoroid kinetic energy loss converted into light (luminous efficiency) was found. It was found that 7% ± 3% of video meteors were also simultaneously detected as specular echoes by radar, larger than the expected 2% − 5% from modelling. Errors in the per-frame position measurements for video meteors were found to be anisotropic, with video speeds be- ing higher on average compared to radar speeds, consistent with more deceleration in specular radar measurements. Most radar detections occurred near the end of their meteor trails, sug- gesting simultaneous observations are biased towards larger, non-fragmenting meteoroids. The peak luminous efficiency was found to be 5:9% at 41 km=s. The magnitude scale and electron line density were found to relate as M = (38:7 ± 1:2) − 2:5 log10 q. These results suggest the masses of higher speed meteoroids are an order of magnitude smaller than previously thought, implying the total meteoroid mass influx for small meteoroids is below earlier estimates. The main uncertainties associated with this analysis are the unknown spectra of individual meteors (which affects estimates of I), and assumptions of the initial iii meteor trail radius (which affects estimates of q). To improve future simultaneous comparisons, an automated video meteor observatory was constructed. This system, named the Canadian Automated Meteor Observatory (CAMO), features a guided camera which tracks meteors in real-time, giving higher precision video measurements of deceleration and fragmentation for comparison to radar measurements. CAMO can also be used to constrain numerical meteoroid ablation models and to measure the meteoroid mass in-flux at Earth. Keywords: meteors, meteoroids radar, video, simultaneous, monte carlo, error simulation, luminous efficiency, ionisation efficiency iv Co-Authorship Statement This thesis dissertation is based on several published/submitted manuscripts: • Weryk, R.J., Brown, P.G., (2012). Simultaneous radar and video meteors – I: metric comparisons. Planetary and Space Science. 62. 132–152. • Weryk, R.J., Brown, P.G., (2012). Simultaneous radar and video meteors – II: photometry and ionisation. Planetary and Space Science, submitted June 22, 2012. • Weryk, R.J., Campbell-Brown, M.D., Wiegert, P.A., Brown, P.G., Krzeminski, Z., Musci, R., (2012). The Canadian Automated Meteor Observatory (CAMO) : System Overview. Icarus, submitted Sept 18, 2012. While writing a thesis often requires input from others, the core of this thesis is a work of my own: all three papers were written by me. However, it is only fair to point out that my advisor (Peter Brown) provided guidance during all stages of my research. He also provided extensive suggestions and reviews of each manuscript prior to submission. With regards to the radar aspects of my project: when I first began my thesis, the radar system existed but had a specific configuration that was not ideal for simultaneous observations. The system settings were not optimal to record overdense meteors, and could not be changed as to keep meteoroid flux measurements consistent. Because of this, I developed my own software to independently detect and analyse meteors, including overdense echoes. The accuracy of the time-of-flight picks were improved from my undergraduate thesis work (Weryk and Brown, 2004), and I implemented the full wave scattering model of Poulter and Baggaley (1977). For the video aspects of my project, the video cameras and intensifiers were available at the start, but data had to be recorded on video tapes, digitised to the computer, and run through v a detection program manually. This proved to be very time consuming, leading me to improve the process by digitising directly to disk and finding simultaneous events from my automated radar detection program. I developed my own analysis software (METAL), including my own procedure for calibrating meteor positions, and even my own automated detection program (ASGARD) for fireball meteors (Weryk et al., 2008). However, the trajectory solver (MILIG) is not mine, but Borovicka’sˇ (1990). For the meteor events used in this thesis, all video data (29 nights) for the Tavistock site were recorded by me. I set up the cameras, and gathered the observations. The Elginfield data was recorded by Jean-Baptiste Kikwaya, but this was also of benefit to him as he required two station video data for his own thesis project. I performed all data analysis for my meteors, including the Elginfield data, and produced every single plot in this thesis. I interpreted my results in order to derive an estimate of the luminous efficiency (τI) for the Gen-III intensified video bandpass. Lastly, the automated video platform (the CAMO system) constructed for Chapter 4 is directly based off the automated detection software (Weryk et al., 2008) which I created. Sig- nificant effort was put (by me) into improving the detection algorithm to run on intensified video imagery, and to improve the summary files automatically generated. I also created the automation software used to control the entire system. However, many of the hardware aspects were not handled by myself, including construction of the roll-off roof shed, fabrication of the camera mounts, and installation of the optics and related hardware. Margaret Campbell-Brown and Paul Wiegert appear as co-authors on the CAMO manuscript. As the principle investigators of the CAMO project, they obtained the necessary funding, contributed ideas during the system development, and reviewed the manuscript prior to submission. Zbyszek Krzeminski and Reto vi Musci are also co-authors on the CAMO manuscript. While both reviewed the manuscript prior to submission, they are mainly responsible for the hardware aspects and day-to-day operations of the system. vii This thesis is dedicated to: Newman, Burton, MacDonald, and Kucherawy for their inspiration and encouragment. viii Acknowledgements Most importantly, I thank Dr. Peter Brown for all his help and encouragement, and for all the opportunities I’ve had throughout my time at Western. His ability to always see the big picture (and to quote obscure journal article references from memory) always amazes me. While I learned how to write programming code on my own, my ability to write scientific publications (which is what counts in the end) is entirely thanks to him. I thank my advisory committee, Martin Houde and Bob Sica, for their support and for helping to keep me on track. I also thank Bob Hawkes, Jim Jones, and the late Doug ReVelle, for their encouragement and advice. Lastly, I thank the many people who have helped me in various ways, whether related to this thesis or not: Margaret Campbell-Brown, Kristine Drew, Kerry Ellis, Wayne Edwards, Alyssa Gilbert, Nicole Kaiser, Toshi Kasuga, Jean-Baptiste Kikwaya, Edward Stokan, Zbyszek Krzeminski, Reto Musci, Jeremie Vaubaillon, Alan Webster, and Paul Wiegert. ix Contents Title Page i Certificate
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