Volcanic Aerosol Simulations of El Chichón and Pinatubo: Stratospheric Impacts and Decay Rates

Using the AER 2-D sulfate aerosol model, we simulate the eruptions of El Chichón, Mt. Pinatubo, and a significantly larger hypothetical eruption. Interannual stratospheric transport based on NCAR-NCEP reanalysis-2 data [Fleming et al., 2007] is used for the historical periods (1982-1990, 1991-1999), thus including QBO and El Nino effects. Aerosol decay rates are compared with available observations, and calculated aerosol size distributions for the different eruptions are contrasted. We show that e-folding decay rates of aerosol extinction vary almost linearly with effective radius. Impacts on zonal-mean ozone density are shown, along with changes in radiative forcing.