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DOI	10.5194/acp-20-1451-2020
	Characterization of aerosol particles at Cabo Verde close to sea level and at the cloud level-Part 2: Ice-nucleating particles in air, cloud and seawater
	Gong X.; Wex H.; Van Pinxteren M.; Triesch N.; Wadinga Fomba K.; Lubitz J.; Stolle C.; Robinson T.-B.; Müller T.; Herrmann H.; Stratmann F.
发表日期	2020
ISSN	1680-7316
起始页码	1451
结束页码	1468
卷号	20 期号:3
英文摘要	Ice-nucleating particles (INPs) in the troposphere can form ice in clouds via heterogeneous ice nucleation. Yet, atmospheric number concentrations of INPs (NINP) are not well characterized, and, although there is some understanding of their sources, it is still unclear to what extend different sources contribute or if all sources are known. In this work, we examined properties of INPs at Cabo Verde (a.k.a. Cape Verde) from different environmental compartments: the oceanic sea surface microlayer (SML), underlying water (ULW), cloud water and the atmosphere close to both sea level and cloud level. Both enrichment and depletion of NINP in SML compared to ULW were observed. The enrichment factor (EF) varied from roughly 0.4 to 11, and there was no clear trend in EF with ice-nucleation temperature. NINP values in PM10 sampled at Cape Verde Atmospheric Observatory (CVAO) at any particular ice-nucleation temperature spanned around 1 order of magnitude below-15 °C, and about 2 orders of magnitude at warmer temperatures (>-12 °C). Among the 17 PM10 samples at CVAO, three PM10 filters showed elevated NINP at warm temperatures, e.g., above 0.01 L-1 at-10 °C. After heating samples at 95 °C for 1 h, the elevated NINP at the warm temperatures disappeared, indicating that these highly ice active INPs were most likely biological particles. INP number concentrations in PM1 were generally lower than those in PM10 at CVAO. About 83 ± 22 %, 67 ± 18 % and 77 ± 14 % (median±standard deviation) of INPs had a diameter > 1 μ m at ice-nucleation temperatures of-12,-15 and-18 °C, respectively. PM1 at CVAO did not show such elevated NINP at warm temperatures. Consequently, the difference in NINP between PM1 and PM10 at CVAO suggests that biological ice-active particles were present in the supermicron size range. NINP in PM10 at CVAO was found to be similar to that on Monte Verde (MV, at 744 m a.s.l.) during noncloud events. During cloud events, most INPs on MV were activated to cloud droplets. When highly ice active particles were present in PM10 filters at CVAO, they were not observed in PM10 filters on MV but in cloud water samples instead. This is direct evidence that these INPs, which are likely biological, are activated to cloud droplets during cloud events. For the observed air masses, atmospheric NINP values in air fit well to the concentrations observed in cloud water. When comparing concentrations of both sea salt and INPs in both seawater and PM10 filters, it can be concluded that sea spray aerosol (SSA) only contributed a minor fraction to the atmospheric NINP. This latter conclusion still holds when accounting for an enrichment of organic carbon in supermicron particles during sea spray generation as reported in literature. © 2020 Author(s).
语种	英语
scopus关键词	aerosol; aerosol composition; cloud radiative forcing; concentration (composition); nucleation; particulate matter; sea level; source apportionment; Cape Verde [Macaronesia]
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/248002
作者单位	Leibniz Institute for Tropospheric Research, Leipzig, Germany; Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Rostock, Germany; Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Wilhelmshaven, Germany
推荐引用方式 GB/T 7714	Gong X.,Wex H.,Van Pinxteren M.,et al. Characterization of aerosol particles at Cabo Verde close to sea level and at the cloud level-Part 2: Ice-nucleating particles in air, cloud and seawater[J],2020,20(3).
APA	Gong X..,Wex H..,Van Pinxteren M..,Triesch N..,Wadinga Fomba K..,...&Stratmann F..(2020).Characterization of aerosol particles at Cabo Verde close to sea level and at the cloud level-Part 2: Ice-nucleating particles in air, cloud and seawater.ATMOSPHERIC CHEMISTRY AND PHYSICS,20(3).
MLA	Gong X.,et al."Characterization of aerosol particles at Cabo Verde close to sea level and at the cloud level-Part 2: Ice-nucleating particles in air, cloud and seawater".ATMOSPHERIC CHEMISTRY AND PHYSICS 20.3(2020).