First observations of long-lived meteor trains with resonance lidar and other optical instruments

In November 1998 the earth passed through a maximum in the cometary materia l responsible for the yearly Leonids meteor shower. The meteor storm event produced numerous examples of long-lived chemiluminescent trails-visible to the naked eye-over New Mexico, where a major observation campaign was cent ered. One trail was detected for over an hour with a CCD camera employing a narrow sodium filter, and many others were observed for over ten minutes e ach. For the first time, sodium densities in such trails were measured whil e also being imaged in sodium light. We have verified one source of long-li ved light emissions-a sodium-catalyzed reaction involving ozone-but it is f ar too weak to explain the visibility of such trails. In addition, we prese nt a new explanation for the cylindrical shell appearance long reported for chemiluminescent trails and show that ozone depletion by chemical processe s is a possible explanation for this phenomenon.