Journal of Geophysical Research: Atmospheres

The effect of recombination and attachment on meteor radar diffusion coefficient profiles

Authors

  • C. S. Lee,

    1. Department of Astronomy and Space Science, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
    2. School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, Australia
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  • J. P. Younger,

    Corresponding author
    1. ATRAD Pty. Ltd., Thebarton, South Australia, Australia
    • School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, Australia
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  • I. M. Reid,

    1. School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia, Australia
    2. ATRAD Pty. Ltd., Thebarton, South Australia, Australia
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  • Y. H. Kim,

    1. Department of Astronomy and Space Science, Chungnam National University, Yuseong-gu, Daejeon, Republic of Korea
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  • J.-H. Kim

    1. Korea Polar Research Institute, Yeonsu-gu, Incheon, Republic of Korea
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Corresponding author: J. P. Younger, School of Chemistry and Physics, University of Adelaide, Adelaide, SA, 5005, Australia. (joel.younger@adelaide.edu.au)

Abstract

[1] Estimates of the ambipolar diffusion coefficient producedusing meteor radar echo decay times display an increasing trend below 80–85 km, which is inconsistent with a diffusion-only theory of the evolution of meteor trails. Data from the 33 MHz meteor radar at King Sejong Station, Antarctica, have been compared with observations from the Aura Earth Observing System Microwave Limb Sounder satellite instrument. It has been found that the height at which the diffusion coefficient gradient reverses follows the height of a constant neutral atmospheric density surface. Numerical simulations of meteor trail diffusion including dissociative recombination with atmospheric ions and three-body attachment of free electrons to neutral molecules indicate that three-body attachment is responsible for the distortion of meteor radar diffusion coefficient profiles at heights below 90 km, including the gradient reversal below 80–85 km. Further investigation has revealed that meteor trails with low initial electron line density produce decay times more consistent with a diffusion-only model of meteor trail evolution.