A two-dimensional model simulation of the EL Chichon volcanic eruption cloud

Using a two-dimensional model of sulfate photochemistry, transport, and aerosol microphysics, a 2-year period following the eruptions of El Chichon have been simulated. Present calculations suggest that the residence time of the cloud in the stratosphere exceeds 2 years. The model reproduces the observed optical depth, lidar backscatter, and infrared extinction coefficients, if about 10 megatonnes of SO2 are injected. The major deficiency of the model is a somewhat too rapid transport.