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The Role of Organic Aerosols in Homogeneous Ice Formation

Kärcher, B. and Koop, T. (2005) The Role of Organic Aerosols in Homogeneous Ice Formation. Atmospheric Chemistry and Physics, 5, pp. 703-714.

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Official URL: http://www.atmos-chem-phys.org/acp/5/703/


Recent field observations suggest that the fraction of organic-containing aerosol particles in ice cloud particles is diminished when compared to the background aerosol prior to freezing. In this work, we use model calculations to investigate possible causes for the observed behavior. In particular, homogeneous freezing processes in cooling air parcels containing aqueous inorganic particles and organic particles are studied with a detailed microphysical model. A disparate water uptake and resulting size differences that occur between organic and inorganic particles prior to freezing are identified as the most likely reason for the poor partitioning of organic aerosols into the ice phase. The differences in water uptake can be caused by changes in the relationship between solute mass fraction and water activity of the supercooled liquid phase, by modifications of the accommodation coefficient for water molecules, or by a combination thereof. The behavior of peak ice saturation ratios and total ice crystal number concentrations is examined, and the dependence of the results on cooling rate is investigated. Finally, processes are discussed that could possibly modify the homogeneous freezing behavior of organic particles.

Document Type:Article
Additional Information:LIDO-Berichtsjahr=2005,
Title:The Role of Organic Aerosols in Homogeneous Ice Formation
AuthorsInstitution or Email of Authors
Koop, T.Inst. f. Physik, Univ. Bielefeld
Journal or Publication Title:Atmospheric Chemistry and Physics
Refereed publication:Yes
In Open Access:Yes
In ISI Web of Science:Yes
Page Range:pp. 703-714
Keywords:Homogenes Gefrieren, organisches Aerosol, Zirrusbildung
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EO - Erdbeobachtung
DLR - Research area:Space
DLR - Program:W EO - Erdbeobachtung
DLR - Research theme (Project):W - Vorhaben Atmosphären- und Klimaforschung (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Atmospheric Trace Species
Deposited By: Ute Löb
Deposited On:19 Mar 2007
Last Modified:11 Nov 2014 21:55

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