Model simulated and satellite observed aerosols in the UTLS with a focus on non-sulfate particles

Abstract:

Simulations with the atmospheric chemistry - general circulation model EMAC, with modal interactive aerosols, and observations by GOMOS on ENVISAT show that sulfate particles from explosive volcanic eruptions dominate the interannual variability of aerosol extinction in the lower stratosphere and the aerosol radiative forcing at the tropopause. To explain the observations and their seasonal cycle in the time period 2002 to 2012, desert dust and organic and black carbon, transported to the lowermost stratosphere by the Asian summer monsoon and tropical convection, are important. This holds also for the net radiative heating by aerosol in the lowermost stratosphere. Comparison with ATSR total aerosol optical depth and IASI dust optical depth at different wavelengths shows that the model is able to represent stratospheric and tropospheric aerosol in a consistent way. It is shown that UTLS-aerosol is sensitive to the parameterizations for desert dust, the aerosol chemistry scheme, the anthropogenic emissions and the horizontal resolution.