Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published January 1998 | public
Journal Article

Size- and Composition-Resolved Externally Mixed Aerosol Model


The need for a numerical algorithm to predict the growth of external mixtures of aerosol populations is common to several current areas of study, including aerosol radiative effects, particle production processes, and pollution source apportionment. This work describes a model that solves this problem for explicit external and internal mixtures for the processes of coagulation, condensation, deposition, activation, and nucleation. The solution is numerically accurate for both particulate mass and number conservation by virtue of a dual-moment sectional method for solute growth. In addition, evaporable components are calculated in moving sections to retain information during particle activation in supersaturated conditions. The model is illustrated by application to the problem of cloud processing in a marine boundary layer capped with a layer of stratus clouds. The aerosol population is tracked in an air parcel circulating within the boundary layer and through the cloud layer. Boundary layer structure and cloud supersaturation profiles are predicted from gradients of observed thermodynamic variables. The model shows the differential growth of particles during cloud processing in two different types of particle populations, one of sea-salt origin and the other of sulfate origin.

Additional Information

LMR is indebted to the National Science Foundation Advanced Study Program at the National Center for Atmospheric Research for providing support for the development of this model. The authors also thank the Office of Naval Research for providing support for field research that demonstrated the need for the work reported here.

Additional details

August 22, 2023
October 25, 2023