Condensation and Coagulation of Aerosol Particles in the Decay Phase of the Stratospheric Aerosol Layer After the Volcanic Eruption

Abstract

The role of particle-growing processes such as coagulation and condensation in the decay phase of the stratospheric aerosol layer enhanced by the volcanic eruption was discussed by using a one-dimensional and time-dependent numerical model which includes eddy diffusion, coagulation, condensation and sedimentation.Result of calculation suggests that the characteristic time of the decay of the stratospheric aerosol layer is about 1.5-3.0 years for the volcanic eruption which injects a large amount of SO2 gas into the stratosphere.

On the Long Term Variation of Stratospheric Aerosol Content After the Eruption of Volcano El Chichón: Lidar Measurements at Nagoya, Japan

“…As pointed out by Iwasaka (1981), after the eruption of Fuego, the decay time is dependent on the observational period. Itabe et al (1977Itabe et al ( , 1980 suggested a long time scale of particle growth due to condensation on the basis of lidar measurements after the eruption of Fuego, but our observation after the El Chichon eruption does not support their view.…”

“…Itabe et al (1977) observed a longer decay time than those from the numerical model, and suggested an importance of particle growth due to condensation (Itabe et al, 1980). Iwasaka and Kobayashi (1983) estimated the effect of microphysical processes on the decay time of the stratospheric aerosol on the basis of a model including condensation growth, coagulation, diffusion, and sedimentation.…”

“…The increase of backscattered lidar signals from the stratospheric aerosol layer was observed by means of a ruby lidar at Nagoya, Japan, after eruptions of El Chichon in Mexico (at the end of March and the beginning of April 1982; Iwasaka et al, 1983;Hayashida and Iwasaka, 1983;Hayashida et al, 1984). The aerosol backscattering coefficient integrated vertically in the stratosphere began to decrease at the end of November 1982.…”