Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 8 3 2008 10.5194/acpd-8-9061-2008 http://www.atmos-chem-phys-discuss.net/8/9061/2008/ http://www.atmos-chem-phys-discuss.net/8/9061/2008/acpd-8-9061-2008.html http://www.atmos-chem-phys-discuss.net/8/9061/2008/acpd-8-9061-2008.pdf 9061 9098 2008-05-20 Modelling of cirrus clouds – Part 2: Competition of different nucleation mechanisms P. Spichtinger peter.spichtinger@env.ethz.ch K. M. Gierens Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany We study the competition of two different freezing mechanisms (homogeneous and heterogeneous freezing) in the same environment for cold cirrus clouds. 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