Stratospheric heating due to El chicon volcanic eruption: Preliminary results using a 3D model

Summary Changes in the stratospheric temperature due to the presence of volcanic aerosols from E1 Chichon eruption have been calculated with the MIT-GIT quasi-geostrophic general circulation model with the addition of the continuity equation for the aerosols. Heating rates are calculated by taking into account the contribution of both solar and planetary radiation. The heating parametrization uses a method based on a simplified delta-Eddington approximation. The infra-red contribution is obtained calculating the emissivity for a given composition of dust. For this purpose a multiple scattering radiative code has been used assuming a 75% sulfuric-acid composition for the aerosols. Results are reported for the second month of our numerical experiment (about four months after the eruption). In particular an analysis is made of the temperature differences calculated between a control, unperturbed run and an interactive, perturbed run in which the aerosol-induced heating is taken into account. Paper presented at the 1° Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 19–22, 1984, Rome.