Lidar observations of sporadic Na layers over Wuhan (30.5°N, 114.4°E) -: art. no. 1345

[1] Based on lidar measurements between March and September 2001, the characteristics of sporadic Na layers (Na-s layers) over Wuhan (30.5degreesN, 114.4degreesE) are presented. Na-s layers were observed on 29 occasions from 275 h observational data. They tended to show a seasonal variation with a maximum occurrence rate in July. The maximum Na density was 24080 cm(-3) which was comparable with those observed at low and high latitudes. Different from the observations at all other sites over the world, most Na-s layers over Wuhan tended to occur around the peak altitudes of the normal Na layers (similar to 92 km). However, a Na-s layer was observed at 112.9 km altitude. The formation of the Na-s layers over Wuhan generally needed a longer time than those at low and high latitudes. The formation processes usually consisted of consecutive density enhancement bursts. The Na-s layers often exhibited broader layer widths than those at low and high latitudes.