Enhanced high-temperature ice nucleation ability of crystallized aerosol particles after preactivation at low temperature

Wagner, Robert; Möhler, Ottmar; Saathoff, H.; Schnaiter, M.

doi:10.1002/2014jd021741

Cited by 18 publications

(33 citation statements)

References 72 publications

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“…These are particles that have already acted as an IN, or have been scavenged by growing ice crystals or were simply exposed to a temperature lower than ∼ 235 K. Wagner et al (2014) investigated aerosol particles before and after pre-activation in the AIDA cloud chamber and showed that the IN efficiency of these particles increased as a result. Ice on the surface of the surrounding mountains and glaciers at JFJ will be sublime in conditions when saturation with respect to ice is < 1.…”

Section: Pre-activated Aerosolmentioning

confidence: 99%

The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch

et al. 2015

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Abstract. During the winter of 2013 and 2014 measurements of cloud microphysical properties over a 5-week period at the high-alpine site Jungfraujoch, Switzerland, were carried out as part of the Cloud Aerosol Characterisation Experiments (CLACE) and the Ice Nucleation Process Investigation and Quantification project (INUPIAQ). Measurements of aerosol properties at a second, lower site, Schilthorn, Switzerland, were used as input for a primary ice nucleation scheme to predict ice nuclei concentrations at Jungfraujoch. Frequent, rapid transitions in the ice and liquid properties of the clouds at Jungfraujoch were identified that led to large fluctuations in ice mass fractions over temporal scales of seconds to hours. During the measurement period we observed high concentrations of ice particles that exceeded 1000 L −1 at temperatures around −15 • C, verified by multiple instruments. These concentrations could not be explained using the usual primary ice nucleation schemes, which predicted ice nucleus concentrations several orders of magnitude smaller than the peak ice crystal number concentrations. Secondary ice production through the Hallett-Mossop process as a possible explanation was ruled out, as the cloud was rarely within the active temperature range for this process. It is shown that other mechanisms of secondary ice particle production cannot explain the highest ice particle concentrations. We describe four possible mechanisms that could lead to high cloud ice concentrations generated from the snowcovered surfaces surrounding the measurement site. Of these we show that hoar frost crystals generated at the cloud enveloped snow surface could be the most important source of cloud ice concentrations. Blowing snow was also observed to make significant contributions at higher wind speeds when ice crystal concentrations were < 100 L −1 .

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Section: Pre-activated Aerosolmentioning

confidence: 99%

The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch

et al. 2015

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“…Thus, the phase state of the aerosol particles (represented by their bounciness) could play a role in the onset of activation, as hinted at in measurements by Ignatius et al (2016), Ladino et al (2014), andWagner et al (2014). As the cloud chamber is generally close to water saturation at the beginning of each expansion, an earlier activation to cloud particles would be expected than is seen here.…”

Section: Discussionmentioning

confidence: 53%

“…Ladino et al, 2014;Wagner et al, 2014). Thus, there could have been a higher chance of ice formation in the respective second cloud activation runs.…”

Section: Discussionmentioning

confidence: 99%

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The efficiency of secondary organic aerosol particles acting as ice-nucleating particles under mixed-phase cloud conditions

Frey

Dorsey

et al. 2018

Atmos. Chem. Phys.

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Abstract. Secondary organic aerosol (SOA) particles have been found to be efficient ice-nucleating particles under the cold conditions of (tropical) upper-tropospheric cirrus clouds. Whether they also are efficient at initiating freezing under slightly warmer conditions as found in mixedphase clouds remains undetermined. Here, we study the icenucleating ability of photochemically produced SOA particles with the combination of the Manchester Aerosol Chamber and Manchester Ice Cloud Chamber. Three SOA systems were tested resembling biogenic and anthropogenic particles as well as particles of different phase state. These are namely α-pinene, heptadecane, and 1,3,5-trimethylbenzene. After the aerosol particles were formed, they were transferred into the cloud chamber, where subsequent quasi-adiabatic cloud activation experiments were performed. Additionally, the ice-forming abilities of ammonium sulfate and kaolinite were investigated as a reference to test the experimental setup.Clouds were formed in the temperature range of −20 to −28.6 • C. Only the reference experiment using dust particles showed evidence of ice nucleation. No ice particles were observed in any other experiment. Thus, we conclude that SOA particles produced under the conditions of the reported experiments are not efficient ice-nucleating particles starting at liquid saturation under mixed-phase cloud conditions.

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“…In the case of frozen solution pockets, ice crystal growth can start when the particle dissolves and the trapped ice is released. For crystalline particles, Wagner et al (2014) referred to this process as deliquescence-induced ice growth. When the pores have connections to the surface, ice crystal growth may be initiated by the pore ice as soon as the air becomes supersaturated with respect to ice.…”

Section: Theoretical Background Of Nucleation and Preservation Of Icementioning

confidence: 99%

Pre-activation of aerosol particles by ice preserved in pores

Marcolli

2017

Atmos. Chem. Phys.

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Abstract. Pre-activation denotes the capability of particles or materials to nucleate ice at lower relative humidities or higher temperatures compared to their intrinsic ice nucleation efficiency after having experienced an ice nucleation event or low temperature before. This review presumes that ice preserved in pores is responsible for pre-activation and analyses pre-activation under this presumption. Idealized trajectories of air parcels are used to discuss the pore characteristics needed for ice to persist in pores and to induce macroscopic ice growth out of the pores. The pore width needed to keep pores filled with water decreases with decreasing relative humidity as described by the inverse Kelvin equation. Thus, narrow pores remain filled with ice well below ice saturation. However, the smaller the pore width, the larger the melting and freezing point depressions within the pores. Therefore, pre-activation due to pore ice is constrained by the melting of ice in narrow pores and the sublimation of ice from wide pores imposing restrictions on the temperature and relative humidity range of pre-activation for cylindrical pores. Ice is better protected in ink-bottle-shaped pores with a narrow opening leading to a large cavity. However, whether pre-activation is efficient also depends on the capability of ice to grow macroscopically, i.e. out of the pore. A strong effect of pre-activation is expected for swelling pores, because at low relative humidity (RH) their openings narrow and protect the ice within them against sublimation. At high relative humidities, they open up and the ice can grow to macroscopic size and form an ice crystal. Similarly, ice protected in pockets is perfectly sheltered against sublimation but needs the dissolution of the surrounding matrix to be effective. Pores partially filled with condensable material may also show preactivation. In this case, complete filling occurs at lower RH than for empty pores and freezing shifts to lower temperatures.Pre-activation experiments confirm that materials susceptible to pre-activation are indeed porous. Pre-activation was observed for clay minerals like illite, kaolinite, and montmorillonite with inherent porosity. The largest effect was observed for the swelling clay mineral montmorillonite. Some materials may acquire porosity, depending on the formation and processing conditions. Particles of CaCO 3 , meteoritic material, and volcanic ash showed pre-activation for some samples or in some studies but not in other ones. Quartz and silver iodide were not susceptible to pre-activation.Atmospheric relevance of pre-activation by ice preserved in pores may not be generally given but depend on the atmospheric scenario. Lower-level cloud seeding by pre-activated particles released from high-level clouds crucially depends on the ability of pores to retain ice at the relative humidities and temperatures of the air masses they pass through. Porous particles that are recycled in wave clouds may show pre-activation with subsequent ice growth as soon as ice sat...

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Enhanced high-temperature ice nucleation ability of crystallized aerosol particles after preactivation at low temperature

Cited by 18 publications

References 72 publications

The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch

The origins of ice crystals measured in mixed-phase clouds at the high-alpine site Jungfraujoch

The efficiency of secondary organic aerosol particles acting as ice-nucleating particles under mixed-phase cloud conditions

Pre-activation of aerosol particles by ice preserved in pores

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