Numerical Study of the Impact of Aerosol-Cloud Interactions during Mesoscale Convective

The focus of this work has been to study the effects of aerosols on cloud properties. A mesoscale convective system (MCS) was identified over Midwestern United States during June 2007, and was selected for the study. Since MCSs are credited for 30-40% of the total rainfall in USA, its vital to understand the aerosol-cloud interaction for such a situation. The extensive capabilities of the Weather Research and Forecasting – Chemistry (WRF – Chem) model was used keeping the physics and chemistry options same for two aerosol scenarios. For the “typical” case WRF – Chem run with hourly input data from the National Emission Inventory 2005, while the “clean” case scenario, had only the background emission values. Although no certain trend can be seen for the the thin and thick clouds with respect to aerosol loading, the overall variation is apparent. Time series analysis of the thick and thin clouds separately showed, that for the clean case, the thick cloud dissipates faster. This in turn, has effect on the total precipitation as well as net radiation.