Articles | Volume 34, issue 12
Ann. Geophys., 34, 1119–1144, 2016
Ann. Geophys., 34, 1119–1144, 2016

Regular paper 02 Dec 2016

Regular paper | 02 Dec 2016

Decay times of transitionally dense specularly reflecting meteor trails and potential chemical impact on trail lifetimes

Wayne K. Hocking1, Reynold E. Silber2, John M. C. Plane3, Wuhu Feng3, and Marcial Garbanzo-Salas4 Wayne K. Hocking et al.
  • 1Department of Physics and Astronomy, University of Western Ontario, London, Ontario, N6A 3K7, Canada
  • 2Department of Earth Sciences, University of Western Ontario, London, Ontario, N6A 3B7, Canada
  • 3School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
  • 4University of Costa Rica, San Jose, Costa Rica

Abstract. Studies of transitionally dense meteor trails using radars which employ specularly reflecting interferometric techniques are used to show that measurable high-temperature chemistry exists at timescales of a few tenths of a second after the formation of these trails. This is a process which is distinct from the ambient-temperature chemistry that is already known to exist at timescales of tens of seconds and longer in long-lived trails. As a consequence, these transitionally dense trails have smaller lifetimes than might be expected if diffusion were the only mechanism for reducing the mean trail electron density. The process has been studied with four SKiYMET radars at latitudes varying from 10 to 75° N, over a period of more than 10 years, 24 h per day. In this paper we present the best parameters to use to represent this behaviour and demonstrate the characteristics of the temporal and latitudinal variability in these parameters. The seasonal, day–night and latitudinal variations correlate reasonably closely with the corresponding variations of ozone in the upper mesosphere. Possible reasons for these effects are discussed, but further investigations of any causative relation are still the subject of ongoing studies.

Short summary
Meteoroids entering the atmosphere produce trails of ionized particles which can be detected with radar. The weakest ones are called underdense (the most common), the strongest are called overdense, and intermediate ones are transitional. Meteor radar signatures are used to determine atmospheric parameters like temperature and winds. We present new results which show the effect of ozone on the transitional trail lifetimes, which may eventually allow radar to measure mesospheric ozone.