Aerosols and Clouds
A parameterization of aerosol activation: 2. Multiple aerosol types
Article first published online: 21 SEP 2012
Copyright 2000 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 105, Issue D5, pages 6837–6844, 16 March 2000
How to Cite
2000), A parameterization of aerosol activation: 2. Multiple aerosol types, J. Geophys. Res., 105(D5), 6837–6844, doi:10.1029/1999JD901161., and (
- Issue published online: 21 SEP 2012
- Article first published online: 21 SEP 2012
- Manuscript Accepted: 9 NOV 1999
- Manuscript Received: 26 FEB 1999
A parameterization of the activation of a lognormal size distribution of aerosols to form cloud droplets is extended to the case of multiple externally mixed lognormal modes, each composed of a uniform internal mixture of soluble and insoluble material. The Köhler theory is used to relate the aerosol size distribution and composition to the number activated as a function of maximum supersaturation. The supersaturation balance is used to determine the maximum supersaturation, accounting for particle growth both before and after the particles are activated. Comparison of the parameterized activation of two competing aerosol modes with detailed numerical simulations of the activation process yields agreement to within 10% under a wide variety of conditions, including diverse size distributions, number concentrations, compositions, and updraft velocities. The parametization error exceeds 10% only when the mode radius of the two size distributions differs by an order of magnitude. Errors for the mass fraction activated are always much less than errors for the number fraction activated.