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A classical-theory-based parameterization of heterogeneous ice nucleation by mineral dust, soot, and biological particles in a global climate model

Hoose, C and Kristjánsson, JE and Chen, JP and Hazra, A (2010) A classical-theory-based parameterization of heterogeneous ice nucleation by mineral dust, soot, and biological particles in a global climate model. Journal of the Atmospheric Sciences, 67 (8). pp. 2483-2503.

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Abstract

An ice nucleation parameterization based on classical nucleation theory, with aerosol-specific parameters derived from experiments, has been implemented into a global climate model-the Community Atmosphere Model (CAM)-Oslo. The parameterization treats immersion, contact, and deposition nucleation by mineral dust, soot, bacteria, fungal spores, and pollen in mixed-phase clouds at temperatures between 0° and -38°C. Immersion freezing is considered for insoluble particles that are activated to cloud droplets, and deposition and contact nucleation are only allowed for uncoated, unactivated aerosols. Immersion freezing by mineral dust is found to be the dominant ice formation process, followed by immersion and contact freezing by soot. The simulated biological aerosol contribution to global atmospheric ice formation is marginal, even with high estimates of their ice nucleation activity, because the number concentration of ice nucleation active biological particles in the atmosphere is low compared to other ice nucleating aerosols. Because of the dominance of mineral dust, the simulated ice nuclei concentrations at temperatures below -20°C are found to correlate with coarse-mode aerosol particle concentrations. The ice nuclei (IN) concentrations in the model agree well overall with in situ continuous flow diffusion chamber measurements. At individual locations, the model exhibits a stronger temperature dependence on IN concentrations than what is observed. The simulated IN composition (77 mineral dust, 23 soot, and 10 -5 biological particles) lies in the range of observed ice nuclei and ice crystal residue compositions.

Item Type: Article
Additional Information: Copyright of this article belongs to American Meteorological Society
Uncontrolled Keywords: Aerosol particle concentrations; Atmospheric ice; Biological Aerosol; Biological particles; Classical nucleation theory; Cloud droplets; Community atmosphere model; Contact nucleation; Continuous flows; Diffusion chamber; Fungal spores; General circulation model; Global climate model; Ice crystals; Ice formations; Ice nucleation; Ice nuclei; Ice particles; Immersion freezing; In-situ; Insoluble particles; Mineral dust; Mixed-phase cloud; Number concentration; Temperature dependence, Atmospheric aerosols; Biological materials; Climate models; Concentration (process); Crystals; Dust; Freezing; Minerals; Nucleation; Parameterization; Silicate minerals; Soot, Ice, aerosol; atmospheric deposition; climate modeling; cloud droplet; deposition; general circulation model; ice crystal; nucleation; parameterization
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 29 May 2015 09:25
Last Modified: 29 May 2015 09:25
URI: http://moeseprints.incois.gov.in/id/eprint/785

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