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Annales Geophysicae An interactive open-access journal of the European Geosciences Union
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Volume 32, issue 10
Ann. Geophys., 32, 1321–1332, 2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 32, 1321–1332, 2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Regular paper 29 Oct 2014

Regular paper | 29 Oct 2014

Meteor trail characteristics observed by high time resolution lidar

Y. J. Liu1, J. M. C. Plane2, B. R. Clemesha1, J. H. Wang3, and X. W. Cheng4 Y. J. Liu et al.
  • 1Instituto Nacional de Pesquisas Espaciais, Avenida dos Astronautas, 1758, 12227-010 São Jose dos Campos, Brazil
  • 2School of Chemistry, University of Leeds, Leeds, UK
  • 3Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, China
  • 4Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China

Abstract. We report and analyse the characteristics of 1382 meteor trails based on a sodium data set of ~ 680 h. The observations were made at Yanqing (115.97° E, 40.47° N), China by a ground-based Na fluorescence lidar. The temporal resolution of the raw profiles is 1.5 s and the altitude resolution is 96 m. We discover some characteristics of meteor trails different from those presented in previous reports. The occurrence heights of the trails follow a double-peak distribution with the peaks at ~ 83.5 km and at ~ 95.5 km, away from the peak height of the regular Na layer. 4.7% of the trails occur below 80 km, and 3.25% above 100 km. 75% of the trails are observed in only one 1.5 s profile, suggesting that the dwell time in the laser beam is not greater than 1.5 s. The peak density of the trails as a function of height is similar to that of the background sodium layer. The raw occurrence height distribution is corrected taking account of three factors which affect the relative lifetime of a trail as a function of height: the meteoroid velocity (which controls the ratio of Na/Na+ ablated); diffusional spreading of the trail; and chemical removal of Na. As a result, the bi-modal distribution is more pronounced. Modelling results show that the higher peak corresponds to a meteoroid population with speeds between 20 and 30 km s−1, whereas the lower peak should arise from much slower particles in a near-prograde orbit. It is inferred that most meteoroids in this data set have masses of ~ 1 mg, in order for ablation to produce sufficient Na atoms to be detected by lidar. Finally, the evolution of longer-duration meteor trails is investigated. Signals at each altitude channel consist of density enhancement bursts with the growth process usually faster than the decay process, and there exists a progressive phase shift among these altitude channels.

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