Ice Nucleation by Aerosol Particles: Experimental Studies Using a Wedge-Shaped Ice Thermal Diffusion Chamber

Schaller, R.; Fukuta, N.

doi:10.1175/1520-0469(1979)036<1788:inbape>2.0.co;2

Cited by 75 publications

(72 citation statements)

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“…Therefore, more water is adsorbed on the AgI surfaces in IMCA-ZINC experiments, which may indeed increase the freezing temperature (for water adsorption on AgI surfaces, see Appendix B4). Condensation freezing studies showed that the highest freezing temperatures are obtained for high supersaturation during activation (Schaller and Fukuta, 1979;Zimmermann et al, 2007), which may increase the amount of water present at the surface of the particle. There is evidence that ice crystals form on specific sites (Bryant et al, 1959).…”

Section: Water Adsorption and Surface Irregularitiessupporting

confidence: 92%

“…Particles with diameters < 20 nm and < 10 nm were essentially inactive at temperatures of 259 and 253 K, respectively. Schaller and Fukuta (1979) investigated deposition, condensation and contact freezing of AgI in their ice thermal diffusion chamber (see Tables 2, 3 and 4). The AgI aerosol was produced by heating an AgI powder on an iron plate.…”

Section: Cloud Chamber Experimentsmentioning

confidence: 99%

“…Contact freezing was observed between 265 and 267 K. This temperature range nearly coincides with the one for condensation freezing. For comparison, Schaller and Fukuta (1979) performed an experiment in immersion mode with the AgI aerosol activated to cloud droplets above the ice nucleation threshold temperature. When the fog had formed, the chamber was cooled.…”

Section: Cloud Chamber Experimentsmentioning

confidence: 99%

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Ice nucleation efficiency of AgI: review and new insights

et al. 2016

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Abstract. AgI is one of the best-investigated ice-nucleating substances. It has relevance for the atmosphere since it is used for glaciogenic cloud seeding. Theoretical and experimental studies over the last 60 years provide a complex picture of silver iodide as an ice-nucleating agent with conflicting and inconsistent results. This review compares experimental ice nucleation studies in order to analyze the factors that influence the ice nucleation ability of AgI. The following picture emerges from this analysis: the ice nucleation ability of AgI seems to be enhanced when the AgI particle is on the surface of a droplet, which is indeed the position that a particle takes when it can freely move in a droplet. The ice nucleation by particles with surfaces exposed to air depends on water adsorption. AgI surfaces seem to be most efficient at nucleating ice when they are exposed to relative humidity at or even above water saturation. For AgI particles that are completely immersed in water, the freezing temperature increases with increasing AgI surface area. Higher threshold freezing temperatures seem to correlate with improved lattice matches as can be seen for AgI-AgCl solid solutions and 3AgI q NH 4 I q 6H 2 O, which have slightly better lattice matches with ice than AgI and also higher threshold freezing temperatures. However, the effect of a good lattice match is annihilated when the surfaces have charges. Also, the ice nucleation ability seems to decrease during dissolution of AgI particles. This introduces an additional history and time dependence for ice nucleation in cloud chambers with short residence times.

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Section: Water Adsorption and Surface Irregularitiessupporting

confidence: 92%

Section: Cloud Chamber Experimentsmentioning

confidence: 99%

Section: Cloud Chamber Experimentsmentioning

confidence: 99%

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Ice nucleation efficiency of AgI: review and new insights

et al. 2016

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“…Ice nucleus activity is known to be highly dependent on both temperature and supersaturation (Schaller and Fukuta, 1979). For measurement of natural ice nuclei above water saturation, there have been various works with the filter method (Huffman, 1973;Langer and Rogers, 1975;Zamurs and Jiusto, 1982;Georgii, 1982 and1985;Berezinskiy and Stepanov, 1986;Rosinski et al, 1987;Morgan, 1988 and.…”

Section: Supersaturation Dependencementioning

confidence: 99%

Natural Ice Nucleus Measurement under High Supersaturation

Mizuno¹,

Fukuta

1995

Journal of the Meteorological Society of Japan

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To understand ice nucleation under high supersaturation in clouds, measurements of natural ice nuclei for supersaturation with respect to water (Sw) up to 10% from -20 to -24C were carried out using a horizontal gradient, continuous flow, ice thermal diffusion chamber after solving the spurious count problem due to ice crystal protrusion on the bottom plate with the addition of a small amount of ethylene glycol. The measurements were made with continental air masses in early summer of 1993 at Salt Lake City, Utah in the United States of America.The measured ice nucleus concentration under the condition of -20C and Sw 5% showed a daily variation. The ice nucleus concentration changed from about 10l-1 in a warm air mass to about 1l-1 in a cold air mass, respectively, before and after the passage of a cold front in the synoptic scale. It was inferred that the instability of the warm air mass helps raise the particulates from or near the ground to increase the ice nucleus concentration. In order to pick out the supersaturation dependence at the various temperatures, the ratio of the ice nucleus concentration (N) to that at water saturation (No) was estimated. On average, Sw increases of 5 and 10% raised the N/No ratio by as much as a factor of two or more, respectively. It was found that a general relationship exists between N/No and Sw, and the slope further steepens above water saturation.

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“…Laboratory studies dealing with deposition ice nuclei have been undertaken since the 1950s but there remains a shortage of information on IN active fraction as a function of time and properties of IN acting as deposition ice nuclei in the atmosphere (Mason and Maybank, 1958;Roberts and Hallett, 1967;Schaller and Fukuta, 1979;Archuleta et al, 2005;Twohy and Poellot, 2005;Kanji and Abbatt, 2006;Möhler et al, 2006;Bundke et al, 2008). In the laboratory, the number of aerosols that activate as IN are measured by exposing an aerosol sample to a known temperature and precisely adjustable level of SS i .…”

Section: Introductionmentioning

confidence: 99%

A new thermal gradient ice nucleation diffusion chamber instrument: design, development and first results using Saharan mineral dust

2009

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Abstract. A new Thermal Gradient ice nucleation DiffusionChamber (TGDC) capable of investigating ice nucleation efficiency of atmospherically important aerosols, termed Ice Nuclei (IN), has been designed, constructed and validated. The TGDC can produce a range of supersaturations with respect to ice (SS i ) over the temperature range of −10 to −34 • C for sufficiently long time needed to observe the ice nucleation by the particles. The novel aspect of this new TGDC is that the chamber is run in static mode with aerosol particles supported on a Teflon substrate, which can be raised and lowered in a controlled way through the SS i profile within the chamber, and nucleation events are directly observed using digital photography. The TGDC consists of two ice coated plates to which a thermal gradient is applied to produce the range of SS i . The design of the TGDC gives the ability to understand time-related ice nucleation event information and to perform experiments at different temperatures and SS i conditions for different IN without changing the thermal gradient within the TGDC. The temperature and SS i conditions of the experimental system are validated by observing (NH 4 ) 2 SO 4 deliquescence and the results are in good agreement with the literature data. First results are presented of the onset ice nucleation for mineral dust sampled from the Saharan Desert, including images of nucleation and statistical distributions of onset ice nucleation SS i as a function of temperature. This paper illustrates how useful this new TGDC is for process level studies of ice nucleation and more experimental investigations are needed to better quantify the role of ice formation in the atmosphere.

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Ice Nucleation by Aerosol Particles: Experimental Studies Using a Wedge-Shaped Ice Thermal Diffusion Chamber

Cited by 75 publications

References 0 publications

Ice nucleation efficiency of AgI: review and new insights

Ice nucleation efficiency of AgI: review and new insights

Natural Ice Nucleus Measurement under High Supersaturation

A new thermal gradient ice nucleation diffusion chamber instrument: design, development and first results using Saharan mineral dust

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