Steven E. Schwartz
Atmospheric Sciences Division
Environmental Sciences Department
Brookhaven National Laboratory
P.O. Box 5000, Building 815E
Upton, NY 11973-5000
631-344-3100
fax 631-344-2887
ses@bnl.gov

C. M. Benkovitz and R. L. McGraw
Brookhaven National Laboratory

Work in this project will enhance, evaluate and apply a hemispheric-scale chemical transport model for tropospheric aerosols and precursor species. Aerosol microphysics is represented by the moments of the radial size distribution; closure of the moment equations is achieved by quadrature methods. This method is highly efficient and accurate for representation of aerosol evolution and processes in complex flowfields. The model is driven by observation-derived synoptic meteorological data permitting model evaluation by comparison of modeled and measured aerosol loading, composition, and microphysical properties at specific locations and times. In future work staged model development will incorporate increasingly detailed representation of aerosol nucleation, condensation, coagulation, dry deposition, wet removal, cloud activation, and transport processes and include multiple species including seasalt, windblown dust, ammonia, and carbonaceous material in addition to sulfate. Successive stages of the model will be run for periods of field measurement campaigns by the Atmospheric Chemistry Program and others aiding both model evaluation and interpretation of controlling processes. Source-tagging will permit determination of mass loading and other properties attributable exogenous aerosol at locations of interest. The moment based aerosol module will be made readily available to other investigators within and outside the Atmospheric Chemistry Program.

A recent article resulting from this research simulates the distribution and loading of sulfur dioxide and sulfate over North America, the North Atlantic, and Europe. Additional information can be found in the viewgraphs from a presentation at the Atmospheric Sciences Program Annual Meeting held in March 2002.