Research

Inverse modeling of aerosols in rigorous microphysical calculations and global chemical transport models. In particular, the adjoint method is used to construct an inverse model of aerosol dynamics, thermodynamics, and chemistry. By itself, such a model can be used to reconstruct aerosol size distributions and estimate growth rate parameters based upon a times series of measurements of an evolving size distribution. Coupled with a newly developed adjoint of the 3D global model (GEOS-Chem), this provides an efficient tool for quantifying the dependence of predicted aerosol concentrations on emissions of aerosol precursor species (SOx, NH3, NOx, DMS, etc), long range transport of primary aerosol, concentrations of gas phase oxidants, and additional model parameters such as deposition rates.

Detailed aerosol modeling of organic carbon on a global scale. Large uncertainties in our present understanding of the sources, identities and fates of secondary organic aerosols, coupled with new research development in these areas, afford ample opportunity for improving current models of secondary organic aerosol. Of particular interest is the role of isoprene, a substantial source of organic carbon in the atmosphere with small, yet appreciable, secondary yields, and the effect that the local chemical environment has on such yields.