A Review of the Representation of Aerosol Mixing State in Atmospheric Models

• Published in: Atmosphere Vol. 10; no. 4; p. 168
• Main Authors: Stevens, Robin, Dastoor, Ashu
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.04.2019
• Subjects: aerosol; Aerosol absorption; Aerosol effects; Aerosol optical properties; Aerosols; Air pollution; air quality; Atmospheric models; black carbon; Climate; Climate models; Cloud condensation nuclei; Condensation nuclei; heterogeneous chemistry; Hygroscopicity; liquid-liquid phase separation; mixing-state; Optical properties; Organic chemistry; radiation; Representations; Thermal properties; Thermodynamic equilibrium; Thermodynamic properties; Weather forecasting; Wet deposition
• ISSN: 2073-4433; 2073-4433
• DOI: 10.3390/atmos10040168

Aerosol mixing state significantly affects concentrations of cloud condensation nuclei (CCN), wet removal rates, thermodynamic properties, heterogeneous chemistry, and aerosol optical properties, with implications for human health and climate. Over the last two decades, significant research effort has gone into finding computationally-efficient methods for representing the most important aspects of aerosol mixing state in air pollution, weather prediction, and climate models. In this review, we summarize the interactions between mixing-state and aerosol hygroscopicity, optical properties, equilibrium thermodynamics and heterogeneous chemistry. We focus on the effects of simplified assumptions of aerosol mixing state on CCN concentrations, wet deposition, and aerosol absorption. We also summarize previous approaches for representing aerosol mixing state in atmospheric models, and we make recommendations regarding the representation of aerosol mixing state in future modelling studies.