An update is provided on the Jet Propulsion Laboratory aerosol backsca
tter climatology database, with emphasis on the impact of the June 199
1 eruption of Mt. Pinatubo. The data set is acquired at thermal infrar
ed wavelengths with a range-gated coherent CO2 lidar system, which has
been in regular operation since 1984. A number of analyses have been
carried out to assess long-term trends in the tropospheric and lower s
tratospheric aerosol backscatter, as observed from the lidar site at P
asadena, California.