Indirect effects of aerosols on warm frontal processes

It is known that aerosols can affect the amount and distribution of precipitation in many different cloud systems through what are referred to as aerosol indirect effects. Aerosol indirect effects on boundary layer clouds and convective systems have received much attention; however, little research has been done to examine the indirect effects of aerosols on warm fronts. It is not known how microphysical processes in these systems respond to increased aerosol concentrations and how these responses will feedback onto the frontal dynamical processes.

Results will be presented on the impacts of increased aerosol concentrations on warm frontal precipitation and possible feedbacks to the frontal dynamics. An extratropical cyclone has been simulated for 48 hours at a 3km grid spacing using the Regional Atmospheric Modeling System (RAMS) under clean background conditions. The same simulation was then repeated except that an aerosol source was introduced into the warm sector of the storm such that enhanced aerosol concentrations became incorporated into the extratropical cyclone. Changes in precipitation patterns will be discussed along with the mechanisms that led to those changes. In addition, given that warm fronts are not strongly dynamically forced, influences of aerosols on warm frontal dynamical features will also be addressed.