Meteor-induced transient sporadic E as inferred from rapid-run ionosonde observations at midlatitudes

Abstract

[1] Observations were made with a rapid-run ionosonde during a 1-month period from the end of July to the end of August 2002 that included the Perseid meteor shower. Ionograms were obtained at 1-minute intervals. All the echo traces below a virtual height of 200 km were hand-scaled for detecting weak and broken traces as well as well-determined sporadic E. Among the scaled E-region traces, a distinct meteor echo persisting for 40 min was observed. This long-duration meteor event was similar to that observed during the Leonid meteor shower in 2001. However the apparent height of the echo traces in the current event first decreased and then increased after equaling the height of a persistent sporadic E layer, while the apparent height of the long-duration meteor echo trace observed in Leonids 2001 remained nearly constant. The descending rate of the meteor echo was approximately 22 m/s, which was considerably greater than that of the tidal ion layer trapped in a downward-moving wind shear node. We ascribe the long-duration meteor echo to a transient and horizontally drifting sporadic E patch generated from meteor trail plasma.