The 1996 Leonid shower as studied with a potassium lidar: Observations andinferred meteoroid sizes

We report on the observation and analysis of meteor trails that are detecte d by ground-based lidar tuned to the D-1 fine structure line of K. The lida r is located at Kuhlungsborn, Germany. The echo profiles are analyzed with a temporal resolution of about 1 s and altitude resolution of 200 m. Identi fication of meteor trails in the large archive of raw data is performed wit h help of an automated computer search code. During the peak of the Leonid meteor shower on the morning of November 17, 1996, we observed seven meteor trails between 0245 and 0445 UT. Their mean altitude was 89.0 km. The dura tion of observation of individual trails ranges from 3 s to similar to 30 m in. We model the probability of observing a meteor trail by ground-based li dar as a function of both altitude distribution and duration of the trails. These distributions depend on the mass distribution, entry velocity, and e ntry angle of the meteoroids, on the altitude-dependent chemical and dynami cal lifetimes of the released K atom, and on the absolute detection sensiti vity of our lidar experiment. From the modeling, we derive the statistical likelihood of detection of trails from meteoroids of a particular size. The se bracket quite well the observed trails. The model also gives estimates o f the probable size of the meteoroids based on characteristics of individua l trails.