Instrument for studies of homogeneous and heterogeneous ice nucleation in free-falling supercooled water droplets

2002 ◽  
Vol 73 (11) ◽  
pp. 3988-3996 ◽  
Author(s):  
Stephen E. Wood ◽  
Marcia B. Baker ◽  
Brian D. Swanson
Keyword(s):  
Supercooled Water ◽  
Ice Nucleation ◽  
Water Droplets ◽  
Free Falling ◽  
Heterogeneous Ice Nucleation

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

2016 ◽  
Author(s):  
Lukas Kaufmann ◽  
Claudia Marcolli ◽  
Beiping Luo ◽  
Thomas Peter
Keyword(s):  
Contact Angle ◽  
Active Site ◽  
Energy Barrier ◽  
Active Sites ◽  
Birch Pollen ◽  
Ice Nucleation ◽  
Freezing Rate ◽  
Water Droplets ◽  
Washing Water ◽  
Heterogeneous Ice Nucleation

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. This reduction is conveniently parameterized in terms of a contact angle α between the ice phase immersed in liquid water and the heterogeneous surface area. 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 and Arizona Test Dust (ATD) and 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 parame-terizations 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 of freezing rate with decreasing temperature is too shallow to be described properly by CNT using the contact angle as the only fit parameter. Birch pollen washing water and small nonadecanol coated water droplets show the reverse behavior with temperature dependencies of freezing rates steeper than predicted by CNT formulations. Good agreement of observations and calculations can be obtained when a prefactor β is introduced to the rate coefficient as second fit parameter. Thus, the following microphysical picture emerges: Heterogeneous freezing occurs on 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 nm2 depending on sample, temperature, and CNT-based parameterization. Two fitting parameters are needed to characterize individual active sites. The contact angle lowers the energy barrier that has to be overcome to form the critical embryo on the site compared to the homogeneous case where the critical embryo develops in the volume of water. The prefactor β is needed to adjust the calculated slope of freezing rate increase with decreasing temperature to the measured one. When it is large, there are many nucleation attempts and nucleation occurs immediately when the temperature is low enough so that the active site can accommodate a critical embryo. This is the case for active sites of birch pollen washing water and the small droplets coated with nonadecanol. If the prefactor is low, the number of nucleation attempts is low and the increase of freezing rate with decreasing temperature is shallow. This is the case for Hoggar Mountain dust, the large droplets coated with nonadecanol, and ATD. Different hypotheses why the value of the prefactor depends on the nature of the active sites are discussed.

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

2017 ◽  
Vol 17 (5) ◽  
pp. 3525-3552 ◽  
Author(s):  
Lukas Kaufmann ◽  
Claudia Marcolli ◽  
Beiping Luo ◽  
Thomas Peter
Keyword(s):  
Contact Angle ◽  
Active Site ◽  
Energy Barrier ◽  
Active Sites ◽  
Birch Pollen ◽  
Ice Nucleation ◽  
Freezing Rate ◽  
Water Droplets ◽  
Washing Water ◽  
Heterogeneous Ice Nucleation

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 nm2, 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. The pre-factor β is needed to adjust the calculated slope of freezing rate increase with temperature decrease. When this slope is steep, this can be interpreted as a high frequency of nucleation attempts, so that nucleation occurs immediately when the temperature is low enough for the active site to accommodate a critical embryo. This is the case for active sites of birch pollen washing water and for small droplets coated with nonadecanol. If the pre-factor is low, the frequency of nucleation attempts is low and the increase in freezing rate with decreasing temperature is shallow. This is the case for Hoggar Mountain dust, the large droplets coated with nonadecanol, and ATD. Various hypotheses why the value of the pre-factor depends on the nature of the active sites are discussed.

scholarly journals Freezing on a Chip—A New Approach to Determine Heterogeneous Ice Nucleation of Micrometer-Sized Water Droplets

Atmosphere ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 140 ◽  
Author(s):  
Thomas Häusler ◽  
Lorenz Witek ◽  
Laura Felgitsch ◽  
Regina Hitzenberger ◽  
Hinrich Grothe
Keyword(s):  
Ice Nucleation ◽  
Water Droplets ◽  
New Approach ◽  
Heterogeneous Ice Nucleation

scholarly journals Volcanic ash ice nucleation activity is variably reduced by aging in water and sulfuric acid: the effects of leaching, dissolution, and precipitation

2022 ◽  
Author(s):  
William D Fahy ◽  
Elena C Maters ◽  
Rona Giese-Miranda ◽  
Michael P Adams ◽  
Leif G Jahn ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Volcanic Ash ◽  
Supercooled Water ◽  
Ice Nucleation ◽  
Water Droplets ◽  
Weather And Climate ◽  
Nucleation Activity ◽  
Ice Nucleation Activity ◽  
Dissolution And Precipitation

Volcanic ash nucleates ice when immersed in supercooled water droplets, giving it the potential to influence weather and climate from local to global scales. This ice nucleation activity (INA) is...

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.

Heterogeneous Ice Nucleation Rate Coefficient of Water Droplets Coated by a Nonadecanol Monolayer

2007 ◽  
Vol 111 (5) ◽  
pp. 2149-2155 ◽  
Author(s):  
B. Zobrist ◽  
T. Koop ◽  
B. P. Luo ◽  
C. Marcolli ◽  
T. Peter
Keyword(s):  
Nucleation Rate ◽  
Rate Coefficient ◽  
Ice Nucleation ◽  
Water Droplets ◽  
Heterogeneous Ice Nucleation

scholarly journals Heterogeneous Ice Nucleation by Soufriere Hills Volcanic Ash Immersed in Water Droplets

PLoS ONE ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. e0169720 ◽  
Author(s):  
T. P. Mangan ◽  
J. D. Atkinson ◽  
J. W. Neuberg ◽  
D. O’Sullivan ◽  
T. W. Wilson ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Ice Nucleation ◽  
Water Droplets ◽  
Soufriere Hills ◽  
Heterogeneous Ice Nucleation
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