LIDAR Metal Density Measurements in the Upper Atmosphere
Abstract
Lidar measurements of Ca, Ca(+), and Na from Dec 1986 to Nov 1986 in the south of France (44N, 6E) are discussed. The Na and Ca layers are compared, emphasizing seasonal changes and mean abundances. The very small mean total Ca abundance, 27 million/sq cm, a factor 100 inferior to the Na total abundance is noted. Simultaneous detection of Ca(+) allows the determination of two major parameters: the ratio of abundances (Ca)/(Ca(+)) related to ion chemistry, and the sum (Ca) + (Ca(+)) directly related to metal source and sink processes above 86 km. The very different values for these parameters measured on Na and Ca impose high constraints on metal modeling which are not easy to meet.