Interactions between Tropospheric Chemistry and Aerosols in a Unified GCM Simulation

Anthropogenic changes in the atmospheric abundances of tropospheric ozone and aerosols make significant contributions to climate change. In turn, climate change affects the abundances of ozone and aerosols, resulting in complicated feedbacks. To move toward understanding interactions and feedbacks among tropospheric chemistry, aerosol formation, and climate change, a unified tropospheric chemistry-aerosol model is developed within the Goddard Institute for Space Studies general circulation model. The model includes a detailed simulation of tropospheric ozone-NO_x-hydrocarbon chemistry and a thermodynamic representation of sulfate/nitrate/ammonium aerosols. Two-way coupling between aerosols and chemistry provides consistent chemical fields for aerosol dynamics and aerosol mass for heterogeneous processes and calculations of gas-phase photolysis rates. Although the current version of the unified model does not include prognostic treatments of black carbon, organic carbon, and mineral dust aerosols, we include effects of these particles on photolysis and heterogeneous processes by using three-dimensional off-line fields. The unified model is applied to examine interactions between tropospheric chemistry and aerosols. This dissertation is the first step in the development of a fully-coupled climate/chemistry/aerosol model