气候变化领域集成服务门户(CCPortal): Two-year statistics of columnar-ice production in stratiform clouds over Hyytiälä, Finland: Environmental conditions and the relevance to secondary ice production

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DOI	10.5194/acp-21-14671-2021
	Two-year statistics of columnar-ice production in stratiform clouds over Hyytiälä, Finland: Environmental conditions and the relevance to secondary ice production
	Li H.; Möhler O.; Petäjä T.; Moisseev D.
发表日期	2021
ISSN	1680-7316
起始页码	14671
结束页码	14686
卷号	21 期号:19
英文摘要	Formation of ice particles in clouds at temperatures of -10 °C or warmer was documented by using groundbased radar observations. At these temperatures, the number concentration of ice-nucleating particles (INPs) is not only expected to be small, but this number is also highly uncertain. In addition, there are a number of studies reporting that the observed number concentration of ice particles exceeds expected INP concentrations, indicating that other ice generation mechanisms, such as secondary ice production (SIP), may play an important role in such clouds. To identify formation of ice crystals and report conditions in which they are generated, W-band cloud radar Doppler spectra observations collected at the Hyytiälä station for more than 2 years were used. Given that at these temperatures ice crystals grow mainly as columns, which have distinct linear depolarization ratio (LDR) values, the spectral LDR was utilized to identify newly formed ice particles. It is found that in 5 %-13% of clouds, where cloud top temperatures are -12 °C or warmer, production of columnar ice is detected. For colder clouds, this percentage can be as high as 33 %; 40 %-50% of columnar-ice-producing events last less than 1 h, while 5 %-15% can persist for more than 6 h. By comparing clouds where columnar crystals are produced and to the ones where these crystals are absent, the columnar-ice-producing clouds tend to have larger values of liquid water path and precipitation intensity. The columnar-ice-producing clouds were subdivided into three categories, using the temperature difference, ΔT, between the altitudes where columns are first detected and cloud top. The cases where ΔT is less than 2K are typically single-layer shallow clouds where needles are produced at the cloud top. In multilayered clouds where 2K < ΔT, columns are produced in a layer that is seeded by ice particles falling from above. This classification allows us to study potential impacts of various SIP mechanisms, such as the Hallet-Mossop process or freezing breakup, on columnar-ice production. To answer the question whether the observed ice particles are generated by SIP in the observed single-layer shallow clouds, ice particle number concentrations were retrieved and compared to several INP parameterizations. It was found that the ice number concentrations tend to be 1-3 orders of magnitude higher than the expected INP concentrations. © Authors 2021
语种	英语
scopus关键词	cloud microphysics; comparative study; concentration (composition); Doppler effect; environmental conditions; formation mechanism; freezing; ground-based measurement; ice crystal; stratiform cloud; temperature profile; Finland; Hyytiala; Pirkanmaa
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/246537
作者单位	State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China; Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland; Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany; Finnish Meteorological Institute, Helsinki, Finland
推荐引用方式 GB/T 7714	Li H.,Möhler O.,Petäjä T.,et al. Two-year statistics of columnar-ice production in stratiform clouds over Hyytiälä, Finland: Environmental conditions and the relevance to secondary ice production[J],2021,21(19).
APA	Li H.,Möhler O.,Petäjä T.,&Moisseev D..(2021).Two-year statistics of columnar-ice production in stratiform clouds over Hyytiälä, Finland: Environmental conditions and the relevance to secondary ice production.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(19).
MLA	Li H.,et al."Two-year statistics of columnar-ice production in stratiform clouds over Hyytiälä, Finland: Environmental conditions and the relevance to secondary ice production".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.19(2021).