We discuss 223 middle atmosphere lidar temperature observations. The r
ecord was collected at Frascati (42 degrees N-13 degrees E), during th
e 41-month period January 1989-May 1992, corresponding to the maximum
of solar cycle 22. The choice of this interval was aimed at minimizing
the temperature variability induced by the 11-year solar cycle. The a
verage climatology over the 41-month period and comparison with a refe
rence atmosphere (CIRA86) are presented. Monthly temperature variabili
ty over the full period, during opposite quasi-biennial oscillation ph
ases and on a short-term scale (0.5-4 h), is analyzed. Results indicat
e the 50-55-km region as less affected by variability caused by the na
tural phenomena considered in the analysis. Due to this minimum in nat
ural noise characterizing the atmospheric temperature just above the s
tratopause, observations of that region are well suited to the detecti
on of possible temperature trends induced by industrial activities.