Results from the University of Toronto continuous flow diffusion chamber at ICIS 2007: instrument intercomparison and ice onsets for different aerosol types

Kanji, Zamin A.; DeMott, Paul J.; Möhler, Ottmar; Abbatt, Jonathan P. D.

doi:10.5194/acp-11-31-2011

Cited by 75 publications

(97 citation statements)

References 42 publications

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“…(2), and total aerosol surface area as required by the parameterization of Niemand et al (2012). The INP types represented in this comparison are Saharan (SD) and Asian dust (AD2), Canary Island dust (CID), ambient particles (Amb), and sprayed/dried Snomax ™ bacterial particle suspensions, as described by Niemand et al (2012) and Kanji et al (2011). In some cases, the mineral dusts were coated by exposure to secondary organic aerosol formation, noted as "cSOA" in Table 1.…”

Section: Maximum Active Freezing Fractions -Derivation Of Calibrationmentioning

confidence: 99%

Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

et al. 2015

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Abstract. Data from both laboratory studies and atmospheric measurements are used to develop an empirical parameterization for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105 % relative humidity with respect to water (RH w ) are taken as a measure of the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developed follows the form of one suggested previously for atmospheric particles of nonspecific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 µm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A calibration factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RH w of 105 % vs. maximum fractions active at higher RH w . Instrumental factors that affect activation behavior vs. RH w in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this calibration factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization, including calibration correction, to predictions of the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first-order approximation in numerical modeling investigations.Published by Copernicus Publications on behalf of the European Geosciences Union.

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Section: Maximum Active Freezing Fractions -Derivation Of Calibrationmentioning

confidence: 99%

Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

et al. 2015

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“…The most abundant minerals occurring in desert aerosols are quartz, calcite, mica, hematite, illite, and gypsum (Kandler et al, 2007). So far, laboratory experiments of heterogeneous freezing have been performed mainly with kaolinite, montmorillonite, and illite (e.g., Hoffer, 1961;Pitter and Pruppacher, 1973;Murray et al, 2011;Pinti et al, 2012, Broadley et al, 2012, and Arizona test dust or several types of natural dust (e.g., Vali, 2008;Connolly et al, 2009;Niedermeier et al, 2011;Kanji et al, 2011;Niemand et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Particle surface area dependence of mineral dust in immersion freezing mode: investigations with freely suspended drops in an acoustic levitator and a vertical wind tunnel

Diehl¹,

Debertshäuser²,

Eppers³

et al. 2014

Atmos. Chem. Phys.

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Abstract. The heterogeneous freezing temperatures of supercooled drops were measured using an acoustic levitator. This technique allows one to freely suspend single drops in the air without any wall contact. Heterogeneous nucleation by two types of illite (illite IMt1 and illite NX) and a montmorillonite sample was investigated in the immersion mode. Drops of 1 mm in radius were monitored by a video camera while cooled down to −28 • C to simulate freezing within the tropospheric temperature range. The surface temperature of the drops was contact-free, determined with an infrared thermometer; the onset of freezing was indicated by a sudden increase of the drop surface temperature. For comparison, measurements with one particle type (illite NX) were additionally performed in the Mainz vertical wind tunnel with drops of 340 µm radius freely suspended. Immersion freezing was observed in a temperature range between −13 and −26 • C as a function of particle type and particle surface area immersed in the drops. Isothermal experiments in the wind tunnel indicated that after the cooling stage freezing still proceeds, at least during the investigated time period of 30 s. The results were evaluated by applying two descriptions of heterogeneous freezing, the stochastic and the singular model. Although the wind tunnel results do not support the time-independence of the freezing process both models are applicable for comparing the results from the two experimental techniques.

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“…5a therefore lie on the water saturation line. Only for Snomax ™ , an artificial snow inducer consisting of freeze-dried Pseudomonas syringae bacteria cells, cell debris and dried culture medium (Lagriffoul et al, 2010), deposition nucleation has been studied extensively (Chernoff and Bertram, 2010;Jones et al, 2011;Kanji et al, 2011;DeMott et al, 2011). More results on freezing experiments with biological particles, also from other habitats, are discussed in Després et al (2012).…”

Section: Primary Biological Aerosol Particlesmentioning

confidence: 99%

Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments

2012

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Abstract.A small subset of the atmospheric aerosol population has the ability to induce ice formation at conditions under which ice would not form without them (heterogeneous ice nucleation). While no closed theoretical description of this process and the requirements for good ice nuclei is available, numerous studies have attempted to quantify the ice nucleation ability of different particles empirically in laboratory experiments. In this article, an overview of these results is provided. Ice nucleation "onset" conditions for various mineral dust, soot, biological, organic and ammonium sulfate particles are summarized. Typical temperaturesupersaturation regions can be identified for the "onset" of ice nucleation of these different particle types, but the various particle sizes and activated fractions reported in different studies have to be taken into account when comparing results obtained with different methodologies. When intercomparing only data obtained under the same conditions, it is found that dust mineralogy is not a consistent predictor of higher or lower ice nucleation ability. However, the broad majority of studies agrees on a reduction of deposition nucleation by various coatings on mineral dust. The ice nucleation active surface site (INAS) density is discussed as a simple and empirical normalized measure for ice nucleation activity. For most immersion and condensation freezing measurements on mineral dust, estimates of the temperature-dependent INAS density agree within about two orders of magnitude. For deposition nucleation on dust, the spread is significantly larger, but a general trend of increasing INAS densities with increasing supersaturation is found. For soot, the presently available results are divergent. Estimated average INAS densities are high for ice-nucleation active bacteria at high subzero temperatures. At the same time, it is shown that INAS densities of some other biological aerosols, like certain pollen grains, fungal spores and diatoms, tend to be similar to those of dust. These particles may owe their high ice nucleation onsets to their large sizes. Surface-area-dependent parameterizations of heterogeneous ice nucleation are discussed. For immersion freezing on mineral dust, fitted INAS densities are available, but should not be used outside the temperature interval of the data they were based on. Classical nucleation theory, if employed with only one fitted contact angle, does not reproduce the observed temperature dependence for immersion nucleation, the temperature and supersaturation dependence for deposition nucleation, and the time dependence of ice nucleation. Formulations of classical nucleation theory with distributions of contact angles offer possibilities to overcome these weaknesses.

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Results from the University of Toronto continuous flow diffusion chamber at ICIS 2007: instrument intercomparison and ice onsets for different aerosol types

Cited by 75 publications

References 42 publications

Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

Particle surface area dependence of mineral dust in immersion freezing mode: investigations with freely suspended drops in an acoustic levitator and a vertical wind tunnel

Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments

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