High-Resolution Modeling of Size-Resolved Stratospheric Aerosol

In certain applications the, so-called, bin or sectional models are not adequate to model aerosol or cloud droplets. Therefore, the authors developed a continuous, high-resolution in size model of aerosol. The application of this model to the stratospheric Junge layer is presented. The equations with which to model the aerosol as well as the physics underlying the equations are described in detail. In the authors’ approach, the role of vertical advection is emphasized, and in particular, a realistic diffusion coefficient that eliminates vigorous, artificial mixing between vertical levels is used. The equations are solved using appropriate and accurate numerical methods. As a test, the one-dimensional version of the model is applied to the stratospheric aerosol for both quiescent and volcanic periods. The results are able to capture some characteristics of the Junge layer, which cannot be modeled with bin models with large diffusion. It is also found that the effect of a volcanic eruption on the aerosol population can be long lasting, up to five or six years.