A single parameter representation of hygroscopic growth and cloud condensation nucleus activity – Part 3: Including surfactant partitioning 1Department of Marine Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC, USA
28 Jan 2013
2Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
Received: 17 August 2012 – Published in Atmos. Chem. Phys. Discuss.: 03 September 2012 Abstract. Atmospheric particles can serve as cloud condensation nuclei in the
atmosphere. The presence of surface active compounds in the particle may
affect the critical supersaturation that is required to activate a particle.
Modelling surfactants in the context of Köhler theory, however, is
difficult because surfactant enrichment at the surface implies that a stable
radial concentration gradient must exist in the droplet. In this study, we
introduce a hybrid model that accounts for partitioning between the bulk and
surface phases in the context of single parameter representations of cloud
condensation nucleus activity. The presented formulation incorporates
analytical approximations of surfactant partitioning to yield a set of
equations that maintain the conceptual and mathematical simplicity of the
single parameter framework. The resulting set of equations allows users of
the single parameter model to account for surfactant partitioning by
applying minor modifications to already existing code.
Revised: 15 January 2013 – Accepted: 16 January 2013 – Published: 28 January 2013
Citation: Petters, M. D. and Kreidenweis, S. M.: A single parameter representation of hygroscopic growth and cloud condensation nucleus activity – Part 3: Including surfactant partitioning, Atmos. Chem. Phys., 13, 1081-1091, doi:10.5194/acp-13-1081-2013, 2013.