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Atmos. Chem. Phys. Discuss., 11, 3161-3180, 2011
www.atmos-chem-phys-discuss.net/11/3161/2011/ doi:10.5194/acpd-11-3161-2011 © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. |
Heterogeneous ice nucleation: bridging stochastic and singular freezing behavior
1Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany
2Dept. of Physics, Michigan Technological University, Houghton, Michigan 49931, USA
Abstract. Heterogeneous ice nucleation, a primary pathway for ice formation in the atmosphere, has been described alternately as being stochastic, in direct analogy with homogeneous nucleation, or singular, with ice nuclei initiating freezing at deterministic temperatures. We present an idealized model that bridges these stochastic and singular descriptions of heterogeneous ice nucleation. This "soccer ball" model treats statistically similar particles as being covered with surface sites (patches of finite area) characterized by different nucleation barriers, but with each surface site following the stochastic nature of ice embryo formation. The model provides a phenomenological explanation for seemingly contradictory experimental results obtained in our research groups. We suggest that ice nucleation is fundamentally a stochastic process but that for realistic atmospheric particle populations this process can be masked by the heterogeneity of surface properties. Full evaluation of the model will require experiments with well characterized ice nucleating particles and the ability to vary both temperature and waiting time for freezing.
Citation: Niedermeier, D., Shaw, R. A., Hartmann, S., Wex, H., Clauss, T., Voigtländer, J., and Stratmann, F.: Heterogeneous ice nucleation: bridging stochastic and singular freezing behavior, Atmos. Chem. Phys. Discuss., 11, 3161-3180, doi:10.5194/acpd-11-3161-2011, 2011.