scholarly journals Temperature-gradient effects on heterogeneous ice nucleation from supercooled water

AIP Advances ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 125122
Author(s):  
Liping Wang ◽  
Weiliang Kong ◽  
Fuxin Wang ◽  
Hong Liu
Keyword(s):  
Temperature Gradient ◽  
Supercooled Water ◽  
Ice Nucleation ◽  
Gradient Effects ◽  
Heterogeneous Ice Nucleation

scholarly journals A technique for quantifying heterogeneous ice nucleation in microlitre supercooled water droplets

2015 ◽  
Vol 8 (6) ◽  
pp. 2437-2447 ◽  
Author(s):  
T. F. Whale ◽  
B. J. Murray ◽  
D. O'Sullivan ◽  
T. W. Wilson ◽  
N. S. Umo ◽  
...  
Keyword(s):  
High Temperature ◽  
Silver Iodide ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Supercooled Water ◽  
Ice Nucleation ◽  
Large Droplet ◽  
Increasing Temperature ◽  
Detection And Quantification ◽  
Heterogeneous Ice Nucleation

Abstract. In many clouds, the formation of ice requires the presence of particles capable of nucleating ice. Ice-nucleating particles (INPs) are rare in comparison to cloud condensation nuclei. However, the fact that only a small fraction of aerosol particles can nucleate ice means that detection and quantification of INPs is challenging. This is particularly true at temperatures above about −20 °C since the population of particles capable of serving as INPs decreases dramatically with increasing temperature. In this paper, we describe an experimental technique in which droplets of microlitre volume containing ice-nucleating material are cooled down at a controlled rate and their freezing temperatures recorded. The advantage of using large droplet volumes is that the surface area per droplet is vastly larger than in experiments focused on single aerosol particles or cloud-sized droplets. This increases the probability of observing the effect of less common, but important, high-temperature INPs and therefore allows the quantification of their ice nucleation efficiency. The potential artefacts which could influence data from this experiment, and other similar experiments, are mitigated and discussed. Experimentally determined heterogeneous ice nucleation efficiencies for K-feldspar (microcline), kaolinite, chlorite, NX-illite, Snomax® and silver iodide are presented.

scholarly journals A technique for quantifying heterogeneous ice nucleation in microlitre supercooled water droplets

2014 ◽  
Vol 7 (9) ◽  
pp. 9509-9536 ◽  
Author(s):  
T. F. Whale ◽  
B. J. Murray ◽  
D. O'Sullivan ◽  
N. S. Umo ◽  
K. J. Baustian ◽  
...  
Keyword(s):  
Silver Iodide ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Supercooled Water ◽  
Ice Nucleation ◽  
Radiative Properties ◽  
Ice Content ◽  
Increasing Temperature ◽  
Mixed Phase Clouds ◽  
Heterogeneous Ice Nucleation

Abstract. The ice content of mixed phase clouds, which contain both supercooled water and ice, affects both their lifetime and radiative properties. In many clouds, the formation of ice requires the presence of particles capable of nucleating ice. One of the most important features of ice nucleating particles (INPs) is that they are rare in comparison to cloud condensation nuclei. However, the fact that only a small fraction of aerosol particles can nucleate ice means that detection and quantification of INPs is challenging. This is particularly true at temperatures above about −20 °C since the population of particles capable of serving as INPs decreases dramatically with increasing temperature. In this paper, we describe an experimental technique in which droplets of microlitre volume containing ice nucleating material are cooled down at a controlled rate and their freezing temperatures recorded. The advantage of using large droplet volumes is that the surface area per droplet is vastly larger than in experiments focused on single aerosol particles or cloud-sized droplets. This increases the probability of observing the effect of less common, but important, high temperature INPs and therefore allows the quantification of their ice nucleation efficiency. The potential artefacts which could influence data from this experiment, and other similar experiments, are mitigated and discussed. Experimentally determined heterogeneous ice nucleation efficiencies for K-feldspar (microcline), kaolinite, chlorite, Snomax®, and silver iodide are presented.

scholarly journals Efficiency of immersion mode ice nucleation on surrogates of mineral dust

2007 ◽  
Vol 7 (19) ◽  
pp. 5081-5091 ◽  
Author(s):  
C. Marcolli ◽  
S. Gedamke ◽  
T. Peter ◽  
B. Zobrist
Keyword(s):  
Contact Angle ◽  
Active Sites ◽  
Quantitative Agreement ◽  
Ice Nucleation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Aqueous Suspensions ◽  
Freezing Temperatures ◽  
Good Agreement ◽  
Heterogeneous Ice Nucleation

Abstract. A differential scanning calorimeter (DSC) was used to explore heterogeneous ice nucleation of emulsified aqueous suspensions of two Arizona test dust (ATD) samples with particle diameters of nominally 0–3 and 0–7 μm, respectively. Aqueous suspensions with ATD concentrations of 0.01–20 wt% have been investigated. The DSC thermograms exhibit a homogeneous and a heterogeneous freezing peak whose intensity ratios vary with the ATD concentration in the aqueous suspensions. Homogeneous freezing temperatures are in good agreement with recent measurements by other techniques. Depending on ATD concentration, heterogeneous ice nucleation occurred at temperatures as high as 256 K or down to the onset of homogeneous ice nucleation (237 K). For ATD-induced ice formation Classical Nucleation Theory (CNT) offers a suitable framework to parameterize nucleation rates as a function of temperature, experimentally determined ATD size, and emulsion droplet volume distributions. The latter two quantities serve to estimate the total heterogeneous surface area present in a droplet, whereas the suitability of an individual heterogeneous site to trigger nucleation is described by the compatibility function (or contact angle) in CNT. The intensity ratio of homogeneous to heterogeneous freezing peaks is in good agreement with the assumption that the ATD particles are randomly distributed amongst the emulsion droplets. The observed dependence of the heterogeneous freezing temperatures on ATD concentrations cannot be described by assuming a constant contact angle for all ATD particles, but requires the ice nucleation efficiency of ATD particles to be (log)normally distributed amongst the particles. Best quantitative agreement is reached when explicitly assuming that high-compatibility sites are rare and that therefore larger particles have on average more and better active sites than smaller ones. This analysis suggests that a particle has to have a diameter of at least 0.1 μm to exhibit on average one active site.

scholarly journals Simulating the influence of primary biological aerosol particles on clouds by heterogeneous ice nucleation

2018 ◽  
Vol 18 (20) ◽  
pp. 15437-15450 ◽  
Author(s):  
Matthias Hummel ◽  
Corinna Hoose ◽  
Bernhard Pummer ◽  
Caroline Schaupp ◽  
Janine Fröhlich-Nowoisky ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Ice Crystals ◽  
Atmospheric Measurements ◽  
Cloud Ice ◽  
Biological Aerosol Particles ◽  
Ice Phase ◽  
Heterogeneous Ice Nucleation

Abstract. Primary ice formation, which is an important process for mixed-phase clouds with an impact on their lifetime, radiative balance, and hence the climate, strongly depends on the availability of ice-nucleating particles (INPs). Supercooled droplets within these clouds remain liquid until an INP immersed in or colliding with the droplet reaches its activation temperature. Only a few aerosol particles are acting as INPs and the freezing efficiency varies among them. Thus, the fraction of supercooled water in the cloud depends on the specific properties and concentrations of the INPs. Primary biological aerosol particles (PBAPs) have been identified as very efficient INPs at high subzero temperatures, but their very low atmospheric concentrations make it difficult to quantify their impact on clouds. Here we use the regional atmospheric model COSMO–ART to simulate the heterogeneous ice nucleation by PBAPs during a 1-week case study on a domain covering Europe. We focus on three highly ice-nucleation-active PBAP species, Pseudomonas syringae bacteria cells and spores from the fungi Cladosporium sp. and Mortierella alpina. PBAP emissions are parameterized in order to represent the entirety of bacteria and fungal spores in the atmosphere. Thus, only parts of the simulated PBAPs are assumed to act as INPs. The ice nucleation parameterizations are specific for the three selected species and are based on a deterministic approach. The PBAP concentrations simulated in this study are within the range of previously reported results from other modeling studies and atmospheric measurements. Two regimes of PBAP INP concentrations are identified: a temperature-limited and a PBAP-limited regime, which occur at temperatures above and below a maximal concentration at around −10 ∘C, respectively. In an ensemble of control and disturbed simulations, the change in the average ice crystal concentration by biological INPs is not statistically significant, suggesting that PBAPs have no significant influence on the average state of the cloud ice phase. However, if the cloud top temperature is below −15 ∘C, PBAP can influence the cloud ice phase and produce ice crystals in the absence of other INPs. Nevertheless, the number of produced ice crystals is very low and it has no influence on the modeled number of cloud droplets and hence the cloud structure.

scholarly journals Comment on evidence for surface-initiated homogenous nucleation

2003 ◽  
Vol 3 (4) ◽  
pp. 3361-3372 ◽  
Author(s):  
J. E. Kay ◽  
V. Tsemekhman ◽  
B. Larson ◽  
M. Baker ◽  
B. Swanson
Keyword(s):  
Laboratory Experiments ◽  
Drop Size ◽  
Supercooled Water ◽  
Ice Nucleation ◽  
Surface Nucleation ◽  
Embryo Formation ◽  
Homogenous Nucleation ◽  
Atmospheric Data ◽  
Water Drops

Abstract. We investigate theoretical, laboratory, and atmospheric evidence for a recently proposed hypothesis: homogenous ice nucleation occurs at the surface, not in the volume, of supercooled water drops. Using existing thermodynamic arguments, laboratory experiments, and atmospheric data, we conclude that ice embryo formation at the surface cannot be confirmed or disregarded. Ice nucleation rates measured as a function of drop size in an air ambient could help distinguish between volume and surface nucleation rates.

scholarly journals Heterogeneous ice nucleation of viscous secondary organic aerosol produced from ozonolysis of <i>α</i>-pinene

2016 ◽  
Vol 16 (10) ◽  
pp. 6495-6509 ◽  
Author(s):  
Karoliina Ignatius ◽  
Thomas B. Kristensen ◽  
Emma Järvinen ◽  
Leonid Nichman ◽  
Claudia Fuchs ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Solid Phase ◽  
Particle Surface ◽  
Amorphous Solid ◽  
Organic Aerosol ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Particle Surface Area ◽  
Semi Solid ◽  
Heterogeneous Ice Nucleation

Abstract. There are strong indications that particles containing secondary organic aerosol (SOA) exhibit amorphous solid or semi-solid phase states in the atmosphere. This may facilitate heterogeneous ice nucleation and thus influence cloud properties. However, experimental ice nucleation studies of biogenic SOA are scarce. Here, we investigated the ice nucleation ability of viscous SOA particles. The SOA particles were produced from the ozone initiated oxidation of α-pinene in an aerosol chamber at temperatures in the range from −38 to −10 °C at 5–15 % relative humidity with respect to water to ensure their formation in a highly viscous phase state, i.e. semi-solid or glassy. The ice nucleation ability of SOA particles with different sizes was investigated with a new continuous flow diffusion chamber. For the first time, we observed heterogeneous ice nucleation of viscous α-pinene SOA for ice saturation ratios between 1.3 and 1.4 significantly below the homogeneous freezing limit. The maximum frozen fractions found at temperatures between −39.0 and −37.2 °C ranged from 6 to 20 % and did not depend on the particle surface area. Global modelling of monoterpene SOA particles suggests that viscous biogenic SOA particles are indeed present in regions where cirrus cloud formation takes place. Hence, they could make up an important contribution to the global ice nucleating particle budget.

scholarly journals Comment on evidence for surface-initiated homogeneous nucleation

2003 ◽  
Vol 3 (5) ◽  
pp. 1439-1443 ◽  
Author(s):  
J. E. Kay ◽  
V. Tsemekhman ◽  
B. Larson ◽  
M. Baker ◽  
B. Swanson
Keyword(s):  
Homogeneous Nucleation ◽  
Laboratory Experiments ◽  
Drop Size ◽  
Supercooled Water ◽  
Ice Nucleation ◽  
Surface Nucleation ◽  
Embryo Formation ◽  
Atmospheric Data ◽  
Water Drops

Abstract. We investigate theoretical, laboratory, and atmospheric evidence for a recently proposed hypothesis: homogeneous ice nucleation initiates at the surface, not in the volume, of supercooled water drops. Using existing thermodynamic arguments, laboratory experiments, and atmospheric data, we conclude that ice embryo formation at the surface cannot be confirmed or disregarded. Ice nucleation rates measured as a function of drop size in an air ambient could help distinguish between volume and surface nucleation rates.

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