Mount Pinatubo Stratospheric Aerosol Decay During 1992 and 1993, as seen by the Camaguey Lidar Station

Stratospheric aerosols measurements from Camaguey, Cuba, between January 1992 and November 1993 are reported. The observations began six months after the Mount Pinatubo eruption, and show the aerosol characteristics during the period of cloud decay. Mean monthly profiles were employed for the study. The backscattering ratio at the peak of the profile shows a decrease from 14.80 at 25 km height in January 1992 to 3.82 at 22 km in December of the same year and 1.61 at 19 km in November of 1993. Although the decrease in altitude of the peak is 3 km for both years, the decrease in scattering ratio is more pronounced in the first year, around 11 units, than in the second, around 2 units. As expected, the trend for the integral of backscattering ratio between 16 and 33 km shows a similar trend, with values of 4.49 + 10-3sr-1 for January 1992 to 1.57 + 10-3sr-1 in December of the same year and 0.40 + 10-3sr-1 for November 1993. This represents a decrease of 3 + 10-3sr-1 for the first year and 1 + 10-3sr-1 for the second year, with a decrease in the entire period of one order of magnitude. Another fact that is revealed by the profiles is the practically monotorlic decreasing trend in the scattering ratio and of the integral, but the height of the peak presents an oscillatory decreasing tendency. The base of the layer was at 18 km in January, 1992 decreasing to 17 km in April and to 16 km in July, oscillating around that height for the rest of the year and for all of 1993, except for June 1993. Finally, some particular characteristics of the mean monthly profiles are shown.