The Importance of Initial Trail Radius on the Apparent Height and Number Distributions of Meteor Echoes

Greenhow, J. S.; Hall, Jason E.

doi:10.1093/mnras/121.2.183

Cited by 50 publications

(29 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We deduced that r 0 is proportional to v 0 and inversely proportional to the atmospheric density. Measurements of r 0 by parallel radar observations of meteors on two wavelengths were carried out at Jodrell Bank (Greenhow and Hall, 1960), Kharkov (Kashcheyev andLebedinets, 1961, 1963), and Kiev (Bairachenko, 1963). From our 1963 paper it is evident that the results of measurements are in satisfactory agreement with theory.…”

Section: Results Of Measurementsmentioning

confidence: 99%

“…Lebedinets estimates that for equipment operating on a wavelength of S m and at an effective minimum detectable line density of 10 12 m~', the true sporadic rate is about a factor of 30 greater than the observed echo rate. Greenhow and Hall (1960) estimate that the percentage of the true influx of meteors detected by a radio system varies from 1.5 at 4-m wavelength to 40 at 17 m. However, the estimates of sporadic flux discussed in section 5, which have been derived from observations at frequencies of 70, 38, and 17 Mc/sec, do not differ by more than a factor of 2 to 4. The lack of agreement between the predicted and the observed variations in rate as a function of wavelength has been attributed to the effect of a decrease in fragmentation among meteors fainter than +5 mag (Hawkins, 1964 …”

Section: Symposium On Metbor Orbits and Dustmentioning

confidence: 90%

“…The results of Greenhow and Hall (1960) indicate that, of the total population of meteors, the fraction n that can be observed with a radar of wavelength X is approximately…”

Section: O-022 O-67--14mentioning

confidence: 99%

“…From the observed velocity distribution and the value of the ionizing probability given by Verniani and Hawkins, it was estimated that the flux of sporadic meteors with mass greater than 1.3X10" 8 g is 1.0X lO-^n" 2 sec" 1 . The effect of diffusion and finite initial trail radius on the radar echo rate of meteors has been discussed by a number of workers (Peregudov, 1958;Fialko, 1960;Greenhow and Hall, 1960;Lebedinets, 1964), who have predicted that equipment operating on short wavelengths «10 m) will detect only a fraction of the meteor population. Lebedinets estimates that for equipment operating on a wavelength of S m and at an effective minimum detectable line density of 10 12 m~', the true sporadic rate is about a factor of 30 greater than the observed echo rate.…”

Section: Symposium On Metbor Orbits and Dustmentioning

confidence: 99%

See 3 more Smart Citations

Meteor orbits and dust; the proceedings of a symposium

Hawkins¹

1967

Smithsonian Contributions to Astrophysics

View full text Add to dashboard Cite

The Proceedings of the Symposium on Meteor Orbit* and Dust is published simultaneously as a NASA Special Publication (SP-135) and as Volume 11 of the Smithsonian Contributions to Astrophysics. This single publication thus serves in a dual capacity to satisfy the requirements of both agencies for the published record of this international meeting.The NASA Special Publications series, begun in 1962, makes available information derived from or of value to NASA activities, and includes such publications as conference proceedings, monographs, data compilations, handbooks, Bourcebooks, and special bibliographies.The IntroductionWe recently completed a general analysis of the atmospheric trajectories of 413 precisely reduced Super-Schmidt photographic meteors (Jacchia, Verniani, and Briggs, 1965). We studied the dependence of heights, lengths, decelerations, and magnitudes on such basic parameters as velocity, angle of incidence, and mass, as well as on derived parameters such as the ablation coefficient and the fragmentation index; the latter were in turn related to the other geometrical and physical characteristics, including the phenomena of wake and terminal blending. The results of the analysis are mainly concerned with physical characteristics of meteors; in this paper we shall limit ourselves to only a few points related to problems of orbits and distribution, namely, physical differences dependent on the type of orbit, peculiarities of individual showers, and the mass scale for photographic meteors.Systematic differences between groups of meteors Systematic differences in some physical characteristics between meteors in short-period and long-period orbits were first pointed out by Jacchia (1958Jacchia ( , 1963. He found that the beginning heights of meteors with aphelion distances greater than 7 a.u. were higher than the corresponding heights of meteors with aphelion distances smaller than 7 a.u. All meteors were, of course, reduced to the same brightness.• Smithsonian Astrophysical Observatory and Harvard College Observatory, Cambridge, Massachusetts.'Smithsonian Astrophysical Observatory and Harvard College Observatory; on leave from Centra Nationals per la Fisica dell'Atmosfera c la Meteorologia del C.N.R., Rome, Italy. * Smithsonian Astrophysical Observatory, Cambridge, Massachusetts.The present general analysis has confirmed the effect found by Jacchia: meteors with aphelion distance smaller than 6 a.u. appear 1.8 km lower than meteors in long-period orbits, reduced to the same velocity, mass, and zenith angle. The maximum light and end heights are correspondingly lower ( fig. 1). This effect is related to the different densities that we find for the two groups: on the average, meteors in short-period orbits appear to be about 1.4 times as dense as meteors in long-period orbits. In addition, for short-period meteors, the density increases as the aphelion distance decreases ( fig. 2). These systematic differences in density could be ascribed to the different conditions in which the meteoroids were formed ...

show abstract

Section: Results Of Measurementsmentioning

confidence: 99%

Section: Symposium On Metbor Orbits and Dustmentioning

confidence: 90%

“…The results of Greenhow and Hall (1960) indicate that, of the total population of meteors, the fraction n that can be observed with a radar of wavelength X is approximately…”

Section: O-022 O-67--14mentioning

confidence: 99%

Section: Symposium On Metbor Orbits and Dustmentioning

confidence: 99%

See 2 more Smart Citations

Meteor orbits and dust; the proceedings of a symposium

Hawkins¹

1967

Smithsonian Contributions to Astrophysics

View full text Add to dashboard Cite

show abstract

“…Meteor radars operating near 30 MHz in the HF and lower VHF bands are not subject to an upper useable height governed by total reflection but rather from the upper detectable height for meteor trails (e.g., Greenhow and Hall 1960). At these frequencies, the number of meteor detections tends to zero near 110 km.…”

Section: Mf/hf Meteor Radarsmentioning

confidence: 99%

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

View full text Add to dashboard Cite

The application of medium-frequency (MF) and high-frequency (HF) partial reflection radar to investigate the neutral upper atmosphere is one of the oldest such techniques still regularly in use. The techniques have been continuously improved and remain a robust and reliable method of obtaining wind velocities, turbulence intensities, electron densities, and measurements of atmospheric structure in the mesosphere lower thermosphere (MLT) region (50 to 110 km). In this paper, we review recent developments, discuss the strengths and weaknesses of the technique, and consider possible improvements.

show abstract

The Potential of Meteor-Burst Communications with Particular Reference to the Comet System

Brown¹

1978

Communication Systems and Random Process Theory

View full text Add to dashboard Cite

The Importance of Initial Trail Radius on the Apparent Height and Number Distributions of Meteor Echoes

Cited by 50 publications

References 0 publications

Meteor orbits and dust; the proceedings of a symposium

Meteor orbits and dust; the proceedings of a symposium

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

The Potential of Meteor-Burst Communications with Particular Reference to the Comet System

Contact Info

Product

Resources

About