Statistical properties of meteors from a simple, passive forward scatter system

A project to determine some long-term statistical properties of the terrestrial meteor flux is described. A passive, 55 MHz (US -TV channel 2), forward-scatter radiometeor detection and simple (Apple IIe) computer logging system is used to record the epoch, duration and peak power of all echoes with durations greater than 0.09 s and less than 2 min. The system has been in continuous routine operation from March 1993 to March 1998 with occasional interruptions due to sporadic E, troposcatter and equipment outages. Over 2,000,000 events have been recorded and logging is continuing on a 24-h basis. Grouping by echo type is done statistically at the data processing stage. Using only a small fraction of the available data, we show that this system produces valid and useful scientific results in spite of the fact that meteor velocities are not obtained. Through computer-aided statistical analysis, some of the milestones achieved are: (a) automatic separation of events into overdense, transition and underdense categories, and compilation of various statistics on these groups or some combination of them; (b) confirmation of a diurnal effect on average underdense trail durations; (c) confirmation of an apparent ozone depletion effect on the durations of overdense meteors; (d) interpretation of an apparent peak-power and duration correlation for overdense echoes in terms of the Manning forward scattering model and (e) confirmation (through a power spectrum analysis of hourly rates) of the presence of sporadic radiant sources of approximately 20° of half-intensity-halfwidth which exhibit a 20–30% 16 day variability.