气候变化领域集成服务门户(CCPortal): Ice nucleation on surrogates of boreal forest SOA particles: Effect of water content and oxidative age

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DOI	10.5194/acp-21-11069-2021
	Ice nucleation on surrogates of boreal forest SOA particles: Effect of water content and oxidative age
	Piedehierro A.A.; Welti A.; Buchholz A.; Korhonen K.; Pullinen I.; Summanen I.; Virtanen A.; Laaksonen A.
发表日期	2021
ISSN	1680-7316
起始页码	11069
结束页码	11078
卷号	21 期号:14
英文摘要	We investigate the effect of water content and oxidative age on ice nucleation using 100gnm monodisperse particles of boreal forest secondary organic aerosol (SOA) surrogates. Ice nucleation experiments are conducted in the temperature range between 210 and 240gK and from ice to water saturation using the Spectrometer for Ice Nuclei (SPIN). The effect of the particle water content on the ice nucleation process is tested by preconditioning α-pinene SOA at different humidities (40g%, 10g% and <1g% RHW). The influence of the particle oxidative age is tested by varying their O:C ratio (oxygen-to-carbon ratio, O:C g1/40.45, 0.8, 1.1). To assess the suitability of α-pinene as a model compound to study the ice nucleation properties of boreal forest SOA and to confirm the atmospheric relevance of our findings, we compare them to measurements of SOA using pine-needle oil or Scots pine tree emissions as precursors. The ice nucleation measurements show that surrogates of boreal forest SOA particles promote only homogeneous ice formation. An effect of preconditioning humidity on homogeneous ice nucleation could be observed. Contrary to the expected behavior, homogeneous freezing is suppressed for SOA particles with high water content (preconditioned at 40g% RHW) and was only observed for SOA preconditioned at low RHW (≤10g%). No dependence of homogeneous freezing on the SOA oxidative age was observed. The results can be explained by a significant change of particulate water diffusivity as a function of humidity (from 10g% to 40g% RHW) at 293gK, where the aerosol is preconditioned. The measurements suggest that at low temperatures, water diffusion into dry SOA particles is slow enough to form a core-shell morphology. The liquid outer layer can equilibrate within the timescale of the experiment and freeze homogeneously. On SOA particles with higher water content, water diffuses faster into the particle, delaying equilibration at the particle surface and preventing the formation of a diluted shell, which can delay homogeneous freezing. We propose that the partial water vapor pressure to which the particles are exposed prior to an experiment can serve as an indicator of whether a core-shell structure is developing. © 2021 Ana A. Piedehierro et al.
语种	英语
scopus关键词	aerosol; boreal forest; freezing; humidity; spectrometer; water content; water vapor; Indicator indicator; Pinus (genus); Pinus sylvestris
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/246713
作者单位	Finnish Meteorological Institute, Helsinki, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
推荐引用方式 GB/T 7714	Piedehierro A.A.,Welti A.,Buchholz A.,et al. Ice nucleation on surrogates of boreal forest SOA particles: Effect of water content and oxidative age[J],2021,21(14).
APA	Piedehierro A.A..,Welti A..,Buchholz A..,Korhonen K..,Pullinen I..,...&Laaksonen A..(2021).Ice nucleation on surrogates of boreal forest SOA particles: Effect of water content and oxidative age.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(14).
MLA	Piedehierro A.A.,et al."Ice nucleation on surrogates of boreal forest SOA particles: Effect of water content and oxidative age".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.14(2021).