Aerosol-Fog Interactions in Stratocumulus Cloud-Base Lowering Fog

We will present results from a large suite of single-column model simulations of cloud-base lowering fog in which we vary the aerosol concentration as well as several environmental conditions to understand how the fog responds to the aerosol under a variety of conditions. We find that increasing aerosol concentration leads to both shorter fog lifetime but increased fog water concentration. This is a somewhat paradoxical result. Our analysis suggests that while the increased fog water concentration and liquid water path is a result of drizzle suppression and reduced water deposition to the surface as is often seen in precipitating stratocumulus clouds, the reduced lifetime appears to be more strongly associated with subtle changes to the microphysical structure of the cloud near cloud base. Similar results are also seen in a 3D case study of cloud base lowering fog as well.