On-going Research at VTech* in collaboration with

Battelle, Pacific Northwest Laboratories

( Leaders: Steven J. Ghan and Richard C. Easter )

and Georgia Institute of Technology

( Leader: Rick D. Saylor )

A detailed global tropospheric chemistry: gaseous species and aqueous species and aerosol model that predicts concentrations of oxidants: e.g. gaseous Hydrogen peroxide$ , and hydroperoxylradical$ ; as well as aerosols: e.g. Methane sulfonic acid (MSA) component of the Aitken mode$ , and MSA component of the accumulation mode$ ; and aerosol precursors: e.g. sulfure dioxide$ , and Dimethyl Sulfide (DMS)$ , coupled to a general circulation model that predicts both cloud water mass$ , and cloud droplet number$ will be further developed ( the current model be referred as a simplified chemistry model and the further developed model be referred as a comprehensive chemistry model ), evaluated, and then used to estimate the direct and indirect radiative impact of anthropogenic aerosols . Both number and mass of several externally-mixed aerosol size modes will be predicted, with internal mixing assumed for the different aerosol components within each mode. Aerosol species to be predicated include sulfate in all aerosol size modes: e.g. sulfate in the Aitken mode$ and sulfate in the accumulation mode$ ; carbonaceous, nitrate, soil dust$ , and sea salt$ . Parallel simulations with and without anthropogenic aerosol will be performed for a global domain. Physically-based models will be used to estimate aerosol radiative properties (including dependence on relative humidity) and aerosol activation as cloud condensation nuclei ( e.g. number activation rate for Aitken mode$ , accumulation mode$ , and coarse mode$ ). The simulated aerosol optical depth and droplet effective radius will be compared with satellite observations.
*Leonard K. Peters : e-mail; Pius C.S. Lee : e-mail
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