气候变化领域集成服务门户(CCPortal): New investigations on homogeneous ice nucleation: the effects of water activity and water saturation formulations

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DOI	10.5194/acp-22-65-2022
	New investigations on homogeneous ice nucleation: the effects of water activity and water saturation formulations
	Baumgartner, Manuel; Rolf, Christian; Grooss, Jens-Uwe; Schneider, Julia; Schorr, Tobias; Moehler, Ottmar; Spichtinger, Peter; Kremer, Martina
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	65
结束页码	91
卷号	22 期号:1 页码:27
英文摘要	Laboratory measurements at the AIDA cloud chamber and airborne in situ observations suggest that the homogeneous freezing thresholds at low temperatures are possibly higher than expected from the so-called Koop line. This finding is of importance, because the ice onset relative humidity affects the cirrus cloud coverage and, at the very low temperatures of the tropical tropopause layer, together with the number of ice crystals also the transport of water vapor into the stratosphere. Both the appearance of cirrus clouds and the amount of stratospheric water feed back to the radiative budget of the atmosphere. In order to explore the enhanced ice onset humidities, we re-examine the entire homogeneous ice nucleation process, ice onset, and nucleated crystal numbers, by means of a two-moment microphysics scheme embedded in the trajectory-based model (CLaMS-Ice) as follows: the well-understood and described theoretical framework of homogeneous ice nucleation includes certain formulations of the water activity of the freezing aerosol particles and the saturation vapor pressure of water with respect to liquid water. However, different formulations are available for both parameters. Here, we present extensive sensitivity simulations testing the influence of three different formulations for the water activity and four for the water saturation on homogeneous ice nucleation. We found that the number of nucleated ice crystals is almost independent of these formulations but is instead sensitive to the size distribution of the freezing aerosol particles. The ice onset humidities, also depending on the particle size, are however significantly affected by the choices of the water activity and water saturation, in particular at cold temperatures less than or similar to 205 K. From the CLaMS-Ice sensitivity simulations, we here provide combinations of water saturation and water activity formulations suitable to reproduce the new, enhanced freezing line.
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:000739110200001
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/273597
作者单位	Johannes Gutenberg University of Mainz; Johannes Gutenberg University of Mainz; Helmholtz Association; Research Center Julich; Helmholtz Association; Karlsruhe Institute of Technology
推荐引用方式 GB/T 7714	Baumgartner, Manuel,Rolf, Christian,Grooss, Jens-Uwe,et al. New investigations on homogeneous ice nucleation: the effects of water activity and water saturation formulations[J],2022,22(1):27.
APA	Baumgartner, Manuel.,Rolf, Christian.,Grooss, Jens-Uwe.,Schneider, Julia.,Schorr, Tobias.,...&Kremer, Martina.(2022).New investigations on homogeneous ice nucleation: the effects of water activity and water saturation formulations.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(1),27.
MLA	Baumgartner, Manuel,et al."New investigations on homogeneous ice nucleation: the effects of water activity and water saturation formulations".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.1(2022):27.