Note on the reaction of the upper atmosphere potassium layer to the 1999 Leonid meteor storm

We have performed an experiment to study the impact of the 1999 Leonid mete or storm on the upper atmosphere potassium layer. For the experiment, we us ed a ground-based K-lidar located at the Observatorio del Teide on the isla nd of Tenerife (28 degreesN, 17 degreesW). As is now known from external so urces, the activity of the storm exhibited a sharp peak of activity on Nove mber 18, 1999 close to 02:05 UT with a full width at half maximum of only 4 5 min. Due to unfavorable weather conditions at our lidar site, we could no t observe the behavior of the K layer immediately before or during the mete or storm. However, about 1 h past the peak of the Leonid storm, the clouds above the site started to show small holes. Hence, between 03:24 and 05:22 UT, we were able to perform lidar soundings of the K layer above our site. From those we can conclude that the 1999 Leonid meteor storm has not led to an outstanding enhancement of the upper atmosphere potassium layer.