Abstract
Measurements of the night-time atmospheric sodium layer have been performed intermittently since 1977, using a dye lidar at Fukuoka, Japan (33.4°N, 130.2°E). Sporadic enhancements of the total column abundance of sodium during the Perseids γ meteor showers were observed on the four sets of nights of August 12-14, 1978, 1979, 1981 and 1983. The sodium abundance increased during nighttime of the shower period, but such correlative increase with permanent meteor shower has not been seen at low latitudes by lidar or twilight observations. Altitude profiles of the layer obtained during the shower show three interesting features. (1) The column abundance of sodium atoms increased with arising of the radiant point of the meteor shower. (2) The peak height of the layer began to decrease slightly about two hours before dawn. (3) The column abundance drastically increased just before dawn.
