气候变化领域集成服务门户(CCPortal): Comparative study on immersion freezing utilizing single-droplet levitation methods

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DOI	10.5194/acp-21-3289-2021
	Comparative study on immersion freezing utilizing single-droplet levitation methods
	Szakáll M.; Debertshäuser M.; Philipp Lackner C.; Mayer A.; Eppers O.; Diehl K.; Theis A.; Kumar Mitra S.; Borrmann S.
发表日期	2021
ISSN	1680-7316
起始页码	3289
结束页码	3316
卷号	21 期号:5
英文摘要	Immersion freezing experiments were performed utilizing two distinct single-droplet levitation methods. In the Mainz vertical wind tunnel, supercooled droplets of 700 μm diameter were freely floated in a vertical airstream at constant temperatures ranging from-5 to-30 °C, where heterogeneous freezing takes place. These investigations under isothermal conditions allow the application of the stochastic approach to analyze and interpret the results in terms of the freezing or nucleation rate. In the Mainz acoustic levitator, 2mm diameter drops were levitated while their temperature was continuously cooling from +20 to-28 °C by adapting to the ambient temperature. Therefore, in this case the singular approach was used for analysis. From the experiments, the densities of ice nucleation active sites were obtained as a function of temperature. The direct comparison of the results from two different instruments indicates a shift in the mean freezing temperatures of the investigated drops towards lower values that was material-dependent. As ice-nucleating particles, seven materials were investigated; two representatives of biological species (fibrous and microcrystalline cellulose), four mineral dusts (feldspar, illite NX, montmorillonite, and kaolinite), and natural Sahara dust. Based on detailed analysis of our results we determined a material-dependent parameter for calculating the freezingtemperature shift due to a change in cooling rate for each investigated particle type. The analysis allowed further classification of the investigated materials to be described by a single-or a multiple-component approach. From our experiences during the present synergetic studies, we listed a number of suggestions for future experiments regarding cooling rates, determination of the drop temperature, purity of the water used to produce the drops, and characterization of the ice-nucleating material. The observed freezing-temperature shift is significantly important for the intercomparison of ice nucleation instruments with different cooling rates. © Author(s) 2021.
语种	英语
scopus关键词	cloud microphysics; comparative study; droplet; experimental study; freezing; isotherm; temperature effect; wind tunnel
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/247089
作者单位	Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, J.-J.-Becherweg 21, Mainz, 55128, Germany; Department of Particle Chemistry, Max Planck Institute of Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
推荐引用方式 GB/T 7714	Szakáll M.,Debertshäuser M.,Philipp Lackner C.,et al. Comparative study on immersion freezing utilizing single-droplet levitation methods[J],2021,21(5).
APA	Szakáll M..,Debertshäuser M..,Philipp Lackner C..,Mayer A..,Eppers O..,...&Borrmann S..(2021).Comparative study on immersion freezing utilizing single-droplet levitation methods.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(5).
MLA	Szakáll M.,et al."Comparative study on immersion freezing utilizing single-droplet levitation methods".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.5(2021).