| DOI: | 10.1002/2016JD024761
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| 论文题名: | Immersion mode ice nucleation measurements with the new Portable Immersion Mode Cooling chAmber (PIMCA) |
| 作者: | Kohn M.; Lohmann U.; Welti A.; Kanji Z.A.
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| 刊名: | Journal of Geophysical Research: Atmospheres
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| ISSN: | 2169897X
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| 出版年: | 2016
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| 卷: | 121, 期:9 | | 起始页码: | 4713
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| 结束页码: | 4733
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| 语种: | 英语
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| 英文关键词: | homogeneous freezing
; online immersion freezing
; Portable Immersion Mode Cooling chAmber (PIMCA)
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| Scopus关键词: | aerosol
; cloud condensation nucleus
; cloud droplet
; freezing
; homogeneity
; ice cover
; measurement method
; parameterization
; particle size
; supercooling
; supersaturation
; Switzerland
; Zurich [Switzerland]
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| 英文摘要: | The new Portable Immersion Mode Cooling chAmber (PIMCA) has been developed for online immersion freezing of single-immersed aerosol particles. PIMCA is a vertical extension of the established Portable Ice Nucleation Chamber (PINC). PIMCA immerses aerosol particles into cloud droplets before they enter PINC. Immersion freezing experiments on cloud droplets with a radius of 5-7 μm at a prescribed supercooled temperature (T) and water saturation can be conducted, while other ice nucleation mechanisms (deposition, condensation, and contact mode) are excluded. Validation experiments on reference aerosol (kaolinite, ammonium sulfate, and ammonium nitrate) showed good agreement with theory and literature. The PIMCA-PINC setup was tested in the field during the Zurich AMBient Immersion freezing Study (ZAMBIS) in spring 2014 in Zurich, Switzerland. Significant concentrations of submicron ambient aerosol triggering immersion freezing at T > 236 K were rare. The mean frozen cloud droplet number concentration was estimated to be 7.22·105 L-1 for T < 238 K and determined from the measured frozen fraction and cloud condensation nuclei (CCN) concentrations predicted for the site at a typical supersaturation of SS = 0.3%. This value should be considered as an upper limit of cloud droplet freezing via immersion and homogeneous freezing processes. The predicted ice nucleating particle (INP) concentration based on measured total aerosol larger than 0.5 μm and the parameterization by DeMott et al. (2010) at T = 238 K is INPD10=54 ± 39 L-1. This is a lower limit as supermicron particles were not sampled with PIMCA-PINC during ZAMBIS. © 2016. The Authors. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/62870
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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作者单位: | Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland; Leibniz-Institute for Tropospheric Research, TROPOS, Leipzig, Germany
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| Recommended Citation: | |
Kohn M.,Lohmann U.,Welti A.,et al. Immersion mode ice nucleation measurements with the new Portable Immersion Mode Cooling chAmber (PIMCA)[J]. Journal of Geophysical Research: Atmospheres,2016-01-01,121(9)
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