Efficiency of immersion mode ice nucleation on surrogates of mineral dust

Marcolli, Claudia; Gedamke, S.; Peter, Thomas; Zobrist, B.

doi:10.5194/acp-7-5081-2007

Cited by 289 publications

(428 citation statements)

References 41 publications

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“…In investigations with continuous-flow diffusion chambers (Welti et al, 2012;Lüönd et al, 2010), many particles are investigated individually and a less steep temperature dependence of heterogeneous nucleation rates compared with the homogeneous case is observed. However, there is strong evidence that the surfaces of most ice-nucleating particles are not uniform with respect to their ability to nucleate ice (e.g., Marcolli et al, 2007;Vali, 2014). Refreeze experiments show that variations of the freezing temperatures between runs are much smaller than the range covered by freezing experiments with many droplets, in accordance with the assumption that specific sites are responsible for freezing (Vali, 2008(Vali, , 2014Peckhaus et al, 2016).…”

Section: Introductionmentioning

confidence: 90%

“…1 typical thermograms of emulsion measurements with Hoggar Mountain dust (panel a), ATD (panel b), and birch pollen washing water (panel c) are shown. For ATD, Marcolli et al (2007) showed that the observed range of heterogeneous freezing temperatures cannot be described by assuming the same contact angle for all ATD particles. Rather, the ice-nucleating sites of ATD particles are required to be of different qualities.…”

Section: Emulsion Measurementsmentioning

confidence: 99%

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Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

et al. 2017

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Abstract. Homogeneous nucleation of ice in supercooled water droplets is a stochastic process. In its classical description, the growth of the ice phase requires the emergence of a critical embryo from random fluctuations of water molecules between the water bulk and ice-like clusters, which is associated with overcoming an energy barrier. For heterogeneous ice nucleation on ice-nucleating surfaces both stochastic and deterministic descriptions are in use. Deterministic (singular) descriptions are often favored because the temperature dependence of ice nucleation on a substrate usually dominates the stochastic time dependence, and the ease of representation facilitates the incorporation in climate models. Conversely, classical nucleation theory (CNT) describes heterogeneous ice nucleation as a stochastic process with a reduced energy barrier for the formation of a critical embryo in the presence of an ice-nucleating surface. The energy reduction is conveniently parameterized in terms of a contact angle α between the ice phase immersed in liquid water and the heterogeneous surface. This study investigates various ice-nucleating agents in immersion mode by subjecting them to repeated freezing cycles to elucidate and discriminate the time and temperature dependences of heterogeneous ice nucleation. Freezing rates determined from such refreeze experiments are presented for Hoggar Mountain dust, birch pollen washing water, Arizona test dust (ATD), and also nonadecanol coatings. For the analysis of the experimental data with CNT, we assumed the same active site to be always responsible for freezing. Three different CNT-based parameterizations were used to describe rate coefficients for heterogeneous ice nucleation as a function of temperature, all leading to very similar results: for Hoggar Mountain dust, ATD, and larger nonadecanol-coated water droplets, the experimentally determined increase in freezing rate with decreasing temperature is too shallow to be described properly by CNT using the contact angle α as the only fit parameter. Conversely, birch pollen washing water and small nonadecanol-coated water droplets show temperature dependencies of freezing rates steeper than predicted by all three CNT parameterizations. Good agreement of observations and calculations can be obtained when a pre-factor β is introduced to the rate coefficient as a second fit parameter. Thus, the following microphysical picture emerges: heterogeneous freezing occurs at ice-nucleating sites that need a minimum (critical) surface area to host embryos of critical size to grow into a crystal. Fits based on CNT suggest that the critical active site area is in the range of 10-50 nm 2 , with the exact value depending on sample, temperature, and CNT-based parameterization. Two fitting parameters are needed to characterize individual active sites. The contact angle α lowers the energy barrier that has to be overcome to form the critical embryo at the site compared to the homogeneous case where the critical embryo develops in the volume of water....

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Section: Introductionmentioning

confidence: 90%

Section: Emulsion Measurementsmentioning

confidence: 99%

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

et al. 2017

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“…When the ice particles are evaporated, we delete this ice size class and the number density is put back into the original liquid size class from which the ice particles nucleated. Besides homogeneous nucleation the model also calculates heterogeneous ice nucleation on ice nuclei, assumed to be mineral dust particles in the immersion mode, similar to the approach by Engel et al (2013) using the active-site-based heterogeneous nucleation parameterization of Marcolli et al (2007). Sedimentation of the ice crystals within the column is taken into account by means of a size-dependent terminal velocity, moving a fraction of them into boxes at lower levels (in vertically stacked Eulerian bins of 100 m depth).…”

Section: Ice Microphysics Schemementioning

confidence: 99%

“…ZOMM has been used previously for heterogeneous ice nucleation in the immersion mode (see Engel et al (2013)) and we closely follow their treatment. For technical details, see Appendix C. We follow Marcolli et al (2007) and describe the nucleation process using active site theory. The mean area of an active site is assumed to be A as = 10 nm 2 .…”

Section: Heterogeneous Nucleation Of Icementioning

confidence: 99%

“…Similar to Engel et al (2013), we will utilize a parameterization for ice nucleation on mineral dust (Arizona test dust, ATD) obtained by Marcolli et al (2007) from freezing experiments. They observed heterogeneous nucleation over a broad temperature range, and concluded that the ability to nucleate ice varies between different ATD particles, leading to the following "active sites" occurrence probability:…”

Section: Appendix B: Rh-dependent Mass Accommodation Of H 2 O On Icementioning

confidence: 99%

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Balloon-borne match measurements of midlatitude cirrus clouds

et al. 2014

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Abstract.Observations of high supersaturations with respect to ice inside cirrus clouds with high ice water content (> 0.01 g kg −1 ) and high crystal number densities (> 1 cm −3 ) are challenging our understanding of cloud microphysics and of climate feedback processes in the upper troposphere. However, single measurements of a cloudy air mass provide only a snapshot from which the persistence of ice supersaturation cannot be judged. We introduce here the "cirrus match technique" to obtain information about the evolution of clouds and their saturation ratio. The aim of these coordinated balloon soundings is to analyze the same air mass twice. To this end the standard radiosonde equipment is complemented by a frost point hygrometer, "SnowWhite", and a particle backscatter detector, "COBALD" (Compact Optical Backscatter AerosoL Detector). Extensive trajectory calculations based on regional weather model COSMO (Consortium for Small-Scale Modeling) forecasts are performed for flight planning, and COSMO analyses are used as a basis for comprehensive microphysical box modeling (with grid scale of 2 and 7 km, respectively). Here we present the results of matching a cirrus cloud to within 2-15 km, realized on 8 June 2010 over Payerne, Switzerland, and a location 120 km downstream close to Zurich. A thick cirrus cloud was detected over both measurement sites. We show that in order to quantitatively reproduce the measured particle backscatter ratios, the smallscale temperature fluctuations not resolved by COSMO must be superimposed on the trajectories. The stochastic nature of the fluctuations is captured by ensemble calculations. Possibilities for further improvements in the agreement with the measured backscatter data are investigated by assuming a very slow mass accommodation of water on ice, the presence of heterogeneous ice nuclei, or a wide span of (spheroidal) particle shapes. However, the resulting improvements from these microphysical refinements are moderate and comparable in magnitude with changes caused by assuming different regimes of temperature fluctuations for clear-sky or cloudysky conditions, highlighting the importance of proper treatment of subscale fluctuations. The model yields good agreement with the measured backscatter over both sites and reproduces the measured saturation ratios with respect to ice over Payerne. Conversely, the 30 % in-cloud supersaturation measured in a massive 4 km thick cloud layer over Zurich cannot be reproduced, irrespective of the choice of meteorological or microphysical model parameters. The measured supersaturation can only be explained by either resorting to an unknown physical process, which prevents the ice particles from consuming the excess humidity, or -much more likely -by a measurement error, such as a contamination of the sensor housing of the SnowWhite hygrometer by a precipitation drop from a mixed-phase cloud just below the cirrus layer or from some very slight rain in the boundary layer. This uncertainty calls for in-flight checks or calibrations of hygrom...

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A computationally efficient description of heterogeneous freezing: A simplified version of the Soccer ball model

Niedermeier

Ervens

Clauß

et al. 2014

Geophysical Research Letters

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In a recent study, the Soccer ball model (SBM) was introduced for modeling and/or parameterizing heterogeneous ice nucleation processes. The model applies classical nucleation theory. It allows for a consistent description of both apparently singular and stochastic ice nucleation behavior, by distributing contact angles over the nucleation sites of a particle population assuming a Gaussian probability density function. The original SBM utilizes the Monte Carlo technique, which hampers its usage in atmospheric models, as fairly time‐consuming calculations must be performed to obtain statistically significant results. Thus, we have developed a simplified and computationally more efficient version of the SBM. We successfully used the new SBM to parameterize experimental nucleation data of, e.g., bacterial ice nucleation. Both SBMs give identical results; however, the new model is computationally less expensive as confirmed by cloud parcel simulations. Therefore, it is a suitable tool for describing heterogeneous ice nucleation processes in atmospheric models.

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Efficiency of immersion mode ice nucleation on surrogates of mineral dust

Cited by 289 publications

References 41 publications

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

Balloon-borne match measurements of midlatitude cirrus clouds

A computationally efficient description of heterogeneous freezing: A simplified version of the Soccer ball model

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