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DOI	10.5194/acp-22-4985-2022
	Enhanced soot particle ice nucleation ability induced by aggregate compaction and densification
	Gao, Kunfeng; Friebel, Franz; Zhou, Chong-Wen; Kanji, Zamin A.
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	4985
结束页码	5016
卷号	22 期号:7 页码:32
英文摘要	Soot particles, acting as ice nucleating particles (INPs), can contribute to cirrus cloud formation, which has an important influence on climate. Aviation activities emitting soot particles into the upper troposphere can potentially impact ice nucleation (IN) in cirrus clouds. Pore condensation and freezing (PCF) is an important ice formation pathway for soot particles in the cirrus regime, which requires the soot INP to have specific morphological properties, i.e., mesopore structures. In this study, the morphology and pore size distribution of two kinds of soot samples were modified by a physical agitation method without any chemical modification by which more compacted soot sample aggregates could be produced compared to the unmodified sample. The IN activities of both fresh and compacted soot particles with different sizes, 60, 100, 200 and 400 nm, were systematically tested by the Horizontal Ice Nucleation Chamber (HINC) under mixed-phase and cirrus-cloud-relevant temperatures (T). Our results show that soot particles are unable to form ice crystals at T > 235 K (homogeneous nucleation temperature, HNT), but IN is observed for compacted and larger-sized soot aggregates (> 200 nm) well below the homogeneous freezing relative humidity (RHhom) for T HNT, demonstrating PCF as the dominating mechanism for soot IN. We also observed that mechanically compacted soot particles can reach a higher particle activation fraction (AF) value for the same T and RH condition compared to the same aggregate size fresh soot particles. The results also reveal a clear size dependence for the IN activity of soot particles with the same degree of compaction, showing that compacted soot particles with large sizes (200 and 400 nm) are more active INPs and can convey the single importance of soot aggregate morphology for the IN ability. In order to understand the role of soot aggregate morphology for its IN activity, both fresh and compacted soot samples were characterized systematically using particle mass and size measurements, comparisons from TEM (transmission electron microscopy) images, soot porosity characteristics from argon (Ar) and nitrogen (N-2) physisorption measurements, as well as soot-water interaction results from DVS (dynamic vapor sorption) measurements. Considering the soot particle physical properties along with its IN activities, the enhanced IN abilities of compacted soot particles are attributed to decreasing mesopore width and increasing mesopore occurrence probability due to the compaction process.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000783538500001
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/273497
作者单位	Beihang University; Beihang University; Swiss Federal Institutes of Technology Domain; ETH Zurich
推荐引用方式 GB/T 7714	Gao, Kunfeng,Friebel, Franz,Zhou, Chong-Wen,et al. Enhanced soot particle ice nucleation ability induced by aggregate compaction and densification[J],2022,22(7):32.
APA	Gao, Kunfeng,Friebel, Franz,Zhou, Chong-Wen,&Kanji, Zamin A..(2022).Enhanced soot particle ice nucleation ability induced by aggregate compaction and densification.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(7),32.
MLA	Gao, Kunfeng,et al."Enhanced soot particle ice nucleation ability induced by aggregate compaction and densification".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.7(2022):32.