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Jerry Y. Harrington, Kara Sulia, and Hugh Morrison

1. Introduction The growth of ice crystals in nature is a complex phenomenon: atmospheric ice attains a variety of shapes that vary among relatively simple hexagonal plates and columns, dendritic structures, rosettes, and often irregular crystals that may be polycrystalline in form. Though crystal shapes vary, they can be characterized by two axis lengths, a and c , and their primary shapes by the aspect ratio ( φ = c / a ). For hexagonal prisms, the a dimension is half the distance

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Steven J. Cooper and Timothy J. Garrett

1. Introduction Many field campaigns and satellite missions have been designed partly in attempt to gain a more accurate characterization of cirrus clouds. For example, the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment (CRYSTAL-FACE), WB-57 Midlatitude Cirrus Cloud Experiment (WB57 MidCiX), and the Tropical Composition, Cloud, and Climate Coupling (TC4) experiment have pursued quantification of these ice clouds through the combination of in situ

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Tsuneya Takahashi and Norihiko Fukuta

FEBRUARY 1988 NOTES AND CORRESPONDENCE 129Ice Crystal Replication with Common Plastic SolutionsTSUNEYA TAKAHASHI* AND NORIHIKO FUKUTADepartment of Meteorology, University of Utah, Salt Lake City, Utah9 February 1987 and 2 June 1987ABSTRACT Use of common plastics, i.e., polystyrene, Plexiglas (polymethyl methacrylate) and Lexan (polycarbonate),was investigated for ice crystal replication. The results suggest that all common

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J. C. Hubbert, S. M. Ellis, W.-Y. Chang, and Y.-C. Liou

(H polarization), thereby causing bias in the SHV polarimetric variables. The two primary mechanisms that cause cross coupling are 1) antenna polarization errors ( McCormick and Hendry 1975 ; Hubbert et al. 2010a ) and 2) forward scatter through a medium of precipitation particles that have a significant nonzero mean canting angle, relative to the horizontal direction in the radar plane of polarization. One such medium is ice crystals that are canted because of an electric field ( Hendry and

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Ottavio A. Vittori and Vittorio Prodi

SEPTEMBER 1967 O T T A V I O A. V I T T O R 1 A N D V I T T O R I O P R O D I 533Scavenging of Atmospheric Particles by Ice Crystals~ OTTAVIO A. VITTORI Osservatorio Mt. Cimone, italy AND VITTORIO PRODIComitato Nazionale ddl' l'~nergia Nucleare, Bologna, Italy(Manuscript received 16 December 1966, in revised form 17 April 1967)ABSTRACT Ice crystals growing in supercooled clouds were

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Robert S. Schrom, Marcus van Lier-Walqui, Matthew R. Kumjian, Jerry Y. Harrington, Anders A. Jensen, and Yao-Sheng Chen

the myriad shapes ice crystals acquire during their lifetimes (e.g., Baker and Lawson 2006 ; Bailey and Hallett 2009 ), along with the complex interactions among these particles. Owing to the lack of theoretical understanding, modeling the evolution of particle shape, mass, and fall speed remains a significant challenge. Recent modeling work has attempted to address this problem by allowing the bulk particle properties of ice hydrometeors (e.g., aspect ratio, density, and size) to evolve freely

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Valery Shcherbakov, Jean-François Gayet, Brad Baker, and Paul Lawson

1. Introduction Ice clouds, especially cirrus, play an important role in the energy balance of the earth–atmosphere system through their interactions with solar and terrestrial radiation ( Liou 1986 , 1992 ; Stephens et al. 1990 ). Their radiative properties are governed by the ice crystals' optical characteristics. The accurate modeling of cirrus single-scattering parameters is of importance in general circulation models ( Kristjánsson et al. 2000 ). The knowledge of these parameters is the

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Charles A. Knight

controversial, although both theory and experiment suggest strongly that the growth occurs by layer nucleation, not spiral steps ( Nelson and Knight 1998 ). Fig . 1. The Nakaya diagram, redrawn from Kobayashi (1961) , with supersaturation expressed as the excess vapor density ρ over saturation with respect to supercooled water, in the growth environment. Decades ago, the finding of high ice crystal concentrations in supercooled water clouds not far below 0°C required an explanation apart from

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Andreas Macke, Johannes Mueller, and Ehrhard Raschke

polyhedral ice crystals are presented based on the geometric optics and the far-field diffraction approximation. Particle shapes range fromvarious hexagonal symmetric particles to highly complex shaped deterministic and random fractals. All calculations are performed at a wavelength of 0.55/~m. Hexagonal symmetric particles show several narrow scatteringpeaks besides the well known 22- and 46- halos. Column-like ice crystals provide neutral points (NP) at largerscattering angles than plate-like ice

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Tsutomu Takahashi

Mi~: 1970 TSUTOMU TAKAHASHI 453Electric Surface Potential of Growing Ice Crystals TSUTOMU TAKAHASItIWater Research Lab., Faculty of Science, Nagoya University, Nagoya, Japan(Manuscript received 20 October 1969, in revised form 12 December 1969)ABSTRACT The surface electric potential of a growing ice crystal was studied for cases of growth by condensation ofwater vapor. Positive

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