The possible effects of El Chichon eruption on atmospheric thermal and chemical structure and surface climate

Abstract

It is suggested that the injection of sulfur oxides and ash into the stratosphere from 1982 El Chichón eruption, would alter the radiative-photochemical balance of the earth's atmosphere which in turn leads to the changes in the vertical temperature and chemical structure -0f the at mosphere and surface climate. In this study one dimensional radiative-convective-photochemical model is used to compute the thermal and chemical response of the atmosphere and the surface climate to enhanced stratospheric aerosol concentrations resulting from the El Chichón eruption. The recent observational data on aerosol optical thickness and optical properties obtained from the global monitoring of the El Chichón cloud has been used as input to model integration. The model allows variable aerosol concentrations and optical properties in time during the life cycle of the volcanic cloud.The preliminary results show that during the first year after the eruption, the global average surface temperature decreases by about 0.9°C while causing significant warming in the lower stratosphere (up to 5°C). The atmosphere and the surface will reach their background teMperature values within roughly 3 to 4 years after the eruption. Also discussed are the implications of El Chichón eruption to stratospheric ozone photochemical cycle.