Winds and Densities from Radar Meteor Trail Returns, 80 to 120 Km

The Influence of the Atmosphere on Radar Meteor Rates

Symposium - International Astronomical Union ◽

10.1017/s0074180900066547 ◽

1980 ◽

Vol 90 ◽

pp. 101-104

Author(s):

W.G. Elford.

Keyword(s):

Initial Diameter ◽

Meteor Trail ◽

Radio Studies ◽

The Difference ◽

Sporadic Meteors ◽

Radar Meteor ◽

Sharp Cutoff ◽

Selection Of

The majority of radio studies of meteors have been carried out at frequencies higher than 17MHz and most of the rate observation at frequencies above 30MHz. At these frequencies a severe height selection of meteors occurs. In Figure 1(a) are shown the normalized height distributions of sporadic meteors observed at Adelaide on frequencies of 27MHz and 2MHz (Brown, 1976). The sharp cutoff of the latter distribution below 87 km is instrumental. The difference in the height distributions is due to the effect of the finite diameter of a meteor trail on its radar detectability. If the trail diameter is ≪ λ signals from the near and far edges reinforce but as the trail expands due to diffusion and the diameter becomes ≃ λ/4, interference reduces the amplitude. A meteor trail, produced by a particle with a velocity of 30 km s−1, has an initial diameter of 0.4m at 80 km, 2.0m at 104 km and 4.0m at 116 km.

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Analyzing Radar Meteor Trail Echoes using the Fresnel Transform Technique: A Signal Processing Viewpoint

Earth Moon and Planets ◽

10.1007/s11038-007-9147-5 ◽

2007 ◽

Vol 101 (1-2) ◽

pp. 27-39 ◽

Cited By ~ 2

Author(s):

Arnab Roy ◽

John F. Doherty ◽

John D. Mathews

Keyword(s):

Signal Processing ◽

Meteor Trail ◽

Fresnel Transform ◽

Radar Meteor

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Global variation of meteor trail plasma turbulence

Annales Geophysicae ◽

10.5194/angeo-29-2277-2011 ◽

2011 ◽

Vol 29 (12) ◽

pp. 2277-2286 ◽

Cited By ~ 6

Author(s):

L. P. Dyrud ◽

J. Urbina ◽

J. T. Fentzke ◽

E. Hibbit ◽

J. Hinrichs

Keyword(s):

Ionospheric Plasma ◽

Plasma Turbulence ◽

Global Scale ◽

Plasma Irregularities ◽

Factors Influencing ◽

Meteor Trail ◽

Diffusion Rates ◽

Ionospheric Plasma Density ◽

Meteor Trails ◽

Radar Meteor

Abstract. We present the first global simulations on the occurrence of meteor trail plasma irregularities. These results seek to answer the following questions: when a meteoroid disintegrates in the atmosphere, will the resulting trail become plasma turbulent? What are the factors influencing the development of turbulence? and how do these trails vary on a global scale? Understanding meteor trail plasma turbulence is important because turbulent meteor trails are visible as non-specular trails to coherent radars. Turbulence also influences the evolution of specular radar meteor trails; this fact is important for the inference of mesospheric temperatures from the trail diffusion rates, and their usage for meteor burst communication. We provide evidence of the significant effect that neutral atmospheric winds and ionospheric plasma density have on the variability of meteor trail evolution and on the observation of non-specular meteor trails. We demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends for non-specular and specular meteor trails.

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