Development and Evaluation of an Externally Mixed Sectional Aerosol Model
Principal Investigators: Rahul Zaveri and Richard Easter
Comparison of the aerosol mixing state from the benchmark MOSAIC-PartMC model compared with the new MOSAIC-mix model that is suitable for implementation in 3-D models. Enlarge Image
The size of atmospheric aerosols range from a few nanometers up to a few microns and can be composed of a wide variety of compounds, such as soluble inorganic salts and acids, insoluble mineral dust, and carbonaceous materials. Particles that are emitted into the atmosphere are externally-mixed. They subsequently undergo chemical and microphysical transformations due to coagulation and condensation of many different semi-volatile gases (organic and inorganic), and produce numerous size and mixing-state distributions with widely different climate-affecting properties. This project has developed and evaluated a mixing-state-resolved sectional aerosol model (MOSAIC-mix) for implementation in three-dimensional models to reliably assess the direct (scattering and absorption) and indirect (cloud formation) radiative forcing effects of atmospheric aerosols. The previously developed MOSAIC-PartMC box-model was used as a benchmark to guide the development of an accurate and efficient representation of the different particle types and mixing states in MOSAIC-mix to reliably predict the optical and CCN properties. Both models were evaluated for CCN activation properties using atmospheric reaction chamber experiments.