Articles | Volume 6, issue 9
Atmos. Chem. Phys., 6, 2593–2649, 2006
Atmos. Chem. Phys., 6, 2593–2649, 2006

  05 Jul 2006

05 Jul 2006

The effect of physical and chemical aerosol properties on warm cloud droplet activation

G. McFiggans1, P. Artaxo2, U. Baltensperger3, H. Coe1, M. C. Facchini4, G. Feingold5, S. Fuzzi4, M. Gysel1,3, A. Laaksonen6, U. Lohmann7, T. F. Mentel8, D. M. Murphy9, C. D. O'Dowd10, J. R. Snider11, and E. Weingartner3 G. McFiggans et al.
  • 1Atmospheric Sciences Group, SEAES, University of Manchester, P.O. Box 88, Manchester, M60 1QD, UK
  • 2Instituto de Fisica, Universidade de Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900 Sao Paulo, Brazil
  • 3Paul Scherrer Institut, Labor für Atmosphärenchemie, 5232 Villigen PSI, Switzerland
  • 4Istituto di Scienze dell'Atmosfera e del Clima, CNR, 40129 Bologna, Italy
  • 5NOAA Environmental Technology Laboratory, 325 Broadway, Boulder, Colorado 80305, USA
  • 6Department of Applied Physics, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland
  • 7Institute for Atmospheric and Climate Science, Schafmattstr. 30, ETH Zurich, 8093 Zurich, Switzerland
  • 8Forschungszentrum Jülich GmbH, ICG-II: Troposphäre, 52425 Jülich, Germany
  • 9NOAA Aeronomy Laboratory, 325 Broadway, Boulder, Colorado 80305, USA
  • 10Department of Physics, National University of Ireland, Galway, Ireland
  • 11University of Wyoming, Department of Atmospheric Science, Laramie, WY 82071, USA

Abstract. The effects of atmospheric aerosol on climate forcing may be very substantial but are quantified poorly at present; in particular, the effects of aerosols on cloud radiative properties, or the "indirect effects" are credited with the greatest range of uncertainty amongst the known causes of radiative forcing. This manuscript explores the effects that the composition and properties of atmospheric aerosol can have on the activation of droplets in warm clouds, so potentially influencing the magnitude of the indirect effect. The effects of size, composition, mixing state and various derived properties are assessed and a range of these properties provided by atmospheric measurements in a variety of locations is briefly reviewed. The suitability of a range of process-level descriptions to capture these aerosol effects is investigated by assessment of their sensitivities to uncertainties in aerosol properties and by their performance in closure studies. The treatment of these effects within global models is reviewed and suggestions for future investigations are made.

Final-revised paper