Abstract
Variations of volcanic aerosol layers originated from eruptions of Mt. El Chichón and Mt. Pinatubo observed in Fukuoka are analyzed. The arrival of the bulk of the El Chichón aerosol layer at Japan was sooner after the eruption, about two weeks after the major eruption, than the arrival of Pinatubo volcanic aerosols which was about three months after the major eruption. The difference is mainly because of the difference in the seasons of the major eruptions between the two events. Although the altitude of the layer of aerosols formed in the case of El Chichón was higher than that of Pinatubo, the speeds of the downward motions were comparable in both cases. It is suggesting that mean radius of the El Chichón aerosols was smaller than that of the Pinatubo aerosols.
