气候变化领域集成服务门户(CCPortal): Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars

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DOI	10.5194/acp-19-10901-2019
	Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars
	Welti A.; Lohmann U.; Kanji Z.A.
发表日期	2019
ISSN	16807316
起始页码	10901
结束页码	10918
卷号	19 期号:16
英文摘要	The relation between the mineralogical characteristics of size-selected feldspar particles from 50 to 800 nm and their ability to act as ice-nucleating particles (INPs) in the immersion mode is presented. Five polymorph members of K-feldspar (two microclines, orthoclase, adularia and sanidine) and four plagioclase samples (three labradorites and a pericline sample) are tested. Microcline was found to be the most active INP in the immersion mode consistent with previous findings. Samples were selected for their differences in typical feldspar properties such as crystal structure, bulk and trace elemental composition, and ordering of the crystal lattice. The properties mentioned are related to the temperature of feldspar crystallization from the magma during formation. Properties characteristic of low-temperature feldspar formation coincide with an increased ability to nucleate ice. Amongst the samples investigated, ice nucleation is most efficient on the crystallographically ordered, triclinic K-feldspar species microcline, while the intermediate and disordered monoclinic K-feldspar polymorphs orthoclase and sanidine nucleate ice at lower temperatures. The ice nucleation ability of disordered triclinic Na=Ca-feldspar is comparable to disordered K-feldspar. The conditions of feldspar rock formation also leave a chemical fingerprint with varying abundance of trace elements in the samples. Xray fluorescence spectroscopy analysis was conducted to determine metal oxide and trace elemental composition of the feldspar samples. The analysis revealed a correlation of trace metal abundance with median freezing temperatures (T50) of the K-feldspar samples allowing us to sort them for their ice nucleation efficiency according to the abundance of specific trace elements. A pronounced size dependence of ice nucleation activity for the feldspar samples is observed, with the activity of smaller-sized particles scaling with surface area or being even higher compared to larger particles. The size dependence varies for different feldspar samples. In particular, microcline exhibited immersion freezing even for 50 nm particles which is unique for heterogeneous ice nucleation of mineral dusts. This suggests that small microcline particles that are susceptible to long-range transport can affect cloud properties via immersion freezing far away from the source. The measurements generally imply that temperatures at which feldspars can affect cloud glaciation depend on the transported particle size in addition to the abundance of these particles. © Author(s) 2019.
语种	英语
scopus关键词	dust; feldspar; fractional crystallization; freezing; magmatic differentiation; nucleation; particle size; plagioclase; polymorphism; trace element
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/144185
作者单位	Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, 8092, Switzerland; Finnish Meteorological Institute, Helsinki, 00101, Finland
推荐引用方式 GB/T 7714	Welti A.,Lohmann U.,Kanji Z.A.. Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars[J],2019,19(16).
APA	Welti A.,Lohmann U.,&Kanji Z.A..(2019).Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars.Atmospheric Chemistry and Physics,19(16).
MLA	Welti A.,et al."Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars".Atmospheric Chemistry and Physics 19.16(2019).