Abstract

Lidar backscatter observations of the stratosphere made at Garmisch-Partenkirchen (47.5°N) from mid-1979 to early 1982 are compared with backscatter cross sections as calculated from measurements of condensation nuclei (r ≧ 0.01 μm) and larger aerosol (r ≧ 0.15 μm, r ≧ 0.25 μm) made from balloons over Laramie, Wyoming (41°N) during the same period. Log normal size distributions are fit to the three particle sizes measured and spherical droplets consisting of a 75% sulfuric acid solution are assumed in calculating the expected backscatter as a function of time. The results clearly indicate that the lower stratosphere (15-17 km) was disturbed as early as December 1979, prior to the eruption of Mt. St. Helens, probably due to minor volcanic activity.