Enhanced ice nucleation activity of coal fly ash aerosol particles initiated by ice-filled pores

Abstract. Ice-nucleating particles (INPs), which are precursors for ice formation in clouds, can alter the microphysical and optical properties of clouds, hence, impacting the cloud lifetimes and hydrological cycles. However, the mechanisms with which these INPs nucleate ice when exposed to different atmospheric conditions are still unclear for some particles. Recently, some INPs with pores or permanent surface defects of regular or irregular geometries have been reported to initiate ice formation at cirrus temperatures via the liquid phase in a two-step process, involving the condensation and freezing of supercooled water inside these pores. This mechanism has therefore been labelled as pore condensation and freezing (PCF). The PCF mechanism allows formation and stabilization of ice germs in the particle without the formation of macroscopic ice. Coal fly ash (CFA) aerosol particles are known to nucleate ice in the immersion freezing mode and may play a significant role in cloud formation. In our current ice nucleation experiments with CFA particles, which we conducted in the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) aerosol and cloud simulation chamber at the Karlsruhe Institute of Technology, Germany, we partly observed a strong increase in the ice-active fraction for experiments performed at temperatures just below the homogeneous freezing of pure water, which could be related to the PCF mechanism. To further investigate the potential of CFA particles undergoing PCF mechanism, we performed a series of temperature-cycling experiments in AIDA. The temperature-cycling experiments involve exposing CFA particles to lower temperatures (down to ~ 228 K), then warming them up to higher temperatures (238 K–273 K) before investigating their ice nucleation properties. For the first time, we report the enhancement of the ice nucleation activity of the CFA particles for temperatures up to 263 K, from which we conclude that it is most likely due to the PCF mechanism. This indicates that ice germs formed in the CFA particles’ pores during cooling remains in the pores during the warming and induces ice crystallization as soon as the pre-activated particles experience ice-supersaturated conditions at warmer temperatures; hence, showing an enhancement in their ice-nucleating ability compared to the scenario where the CFA particles are directly probed at warmer temperatures without temporary cooling. The enhancement in the ice nucleation ability showed a positive correlation with the specific surface area and porosity of the particles. On the one hand, the PCF mechanism could be the prevalent nucleation mode for intrinsic ice formation at cirrus temperatures rather than the previously acclaimed deposition mode. On the other, the PCF mechanism can also play a significant role in mixed-phase cloud formation in a case where the CFA particles are injected from higher altitudes and then transported to lower altitudes after being exposed to lower temperatures.

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Enhanced ice nucleation activity of coal fly ash aerosol particles initiated by ice-filled pores

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-8783-2019 ◽

2019 ◽

Vol 19 (13) ◽

pp. 8783-8800 ◽

Cited By ~ 10

Author(s):

Nsikanabasi Silas Umo ◽

Robert Wagner ◽

Romy Ullrich ◽

Alexei Kiselev ◽

Harald Saathoff ◽

...

Keyword(s):

Coal Fly Ash ◽

Aerosol Particles ◽

Ice Nucleation ◽

Temperature Cycling ◽

Cloud Formation ◽

Ice Formation ◽

Strong Increase ◽

Active Fraction ◽

Nucleation Activity ◽

Ice Nucleation Activity

Abstract. Ice-nucleating particles (INPs), which are precursors for ice formation in clouds, can alter the microphysical and optical properties of clouds, thereby impacting the cloud lifetimes and hydrological cycles. However, the mechanisms with which these INPs nucleate ice when exposed to different atmospheric conditions are still unclear for some particles. Recently, some INPs with pores or permanent surface defects of regular or irregular geometries have been reported to initiate ice formation at cirrus temperatures via the liquid phase in a two-step process, involving the condensation and freezing of supercooled water inside these pores. This mechanism has therefore been labelled pore condensation and freezing (PCF). The PCF mechanism allows formation and stabilization of ice germs in the particle without the formation of macroscopic ice. Coal fly ash (CFA) aerosol particles are known to nucleate ice in the immersion freezing mode and may play a significant role in cloud formation. In our current ice nucleation experiments with a particular CFA sample (CFA_UK), which we conducted in the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) aerosol and cloud simulation chamber at the Karlsruhe Institute of Technology (KIT), Germany, we observed a strong increase (at a threshold relative humidity with respect to ice of 101 %–105 %) in the ice-active fraction for experiments performed at temperatures just below the homogeneous freezing of pure water. This observed strong increase in the ice-active fraction could be related to the PCF mechanism. To further investigate the potential of CFA particles undergoing the PCF mechanism, we performed a series of temperature-cycling experiments in AIDA. The temperature-cycling experiments involve exposing CFA particles to lower temperatures (down to ∼228 K), then warming them up to higher temperatures (238–273 K) before investigating their ice nucleation properties. For the first time, we report the enhancement of the ice nucleation activity of the CFA particles for temperatures up to 263 K, from which we conclude that it is most likely due to the PCF mechanism. This indicates that ice germs formed in the CFA particles' pores during cooling remain in the pores during warming and induce ice crystallization as soon as the pre-activated particles experience ice-supersaturated conditions at higher temperatures; hence, these pre-activated particles show an enhancement in their ice-nucleating ability compared with the scenario where the CFA particles are directly probed at higher temperatures without temporary cooling. The enhancement in the ice nucleation ability showed a positive correlation with the specific surface area and porosity of the particles. On the one hand, the PCF mechanism can play a significant role in mixed-phase cloud formation in a case where the CFA particles are injected from higher altitudes and then transported to lower altitudes after being exposed to lower temperatures. On the other hand, the PCF mechanism could be the prevalent nucleation mode for ice formation at cirrus temperatures rather than the previously acclaimed deposition mode.

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Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-2541-2012 ◽

2012 ◽

Vol 12 (5) ◽

pp. 2541-2550 ◽

Cited By ~ 150

Author(s):

B. G. Pummer ◽

H. Bauer ◽

J. Bernardi ◽

S. Bleicher ◽

H. Grothe

Keyword(s):

Radiative Forcing ◽

Pollen Grains ◽

Ice Nucleation ◽

Cloud Formation ◽

Distribution Area ◽

Ice Cloud ◽

Ice Nuclei ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact

Abstract. The ice nucleation of bioaerosols (bacteria, pollen, spores, etc.) is a topic of growing interest, since their impact on ice cloud formation and thus on radiative forcing, an important parameter in global climate, is not yet fully understood. Here we show that pollen of different species strongly differ in their ice nucleation behaviour. The average freezing temperatures in laboratory experiments range from 240 to 255 K. As the most efficient nuclei (silver birch, Scots pine and common juniper pollen) have a distribution area up to the Northern timberline, their ice nucleation activity might be a cryoprotective mechanism. Far more intriguingly, it has turned out that water, which has been in contact with pollen and then been separated from the bodies, nucleates as good as the pollen grains themselves. The ice nuclei have to be easily-suspendable macromolecules located on the pollen. Once extracted, they can be distributed further through the atmosphere than the heavy pollen grains and so presumably augment the impact of pollen on ice cloud formation even in the upper troposphere. Our experiments lead to the conclusion that pollen ice nuclei, in contrast to bacterial and fungal ice nucleating proteins, are non-proteinaceous compounds.

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Subpollen particles (SPP) of birch as carriers of ice nucleating macromolecules

10.5194/bg-2021-8 ◽

2021 ◽

Author(s):

Julia Burkart ◽

Jürgen Gratzl ◽

Teresa M. Seifried ◽

Paul Bieber ◽

Hinrich Grothe

Keyword(s):

Protein Concentration ◽

Birch Pollen ◽

Pollen Grains ◽

Ice Nucleation ◽

Cloud Formation ◽

Ultrapure Water ◽

Fluorescence Excitation ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Relationship

Abstract. Within the last years pollen grains have gained increasing attention due to their cloud forming potential. Especially the discovery that ice nucleating macromolecules (INM) or subpollen particles (SPP) obtained from pollen grains are able to initiate freezing has stirred up interest in pollen. INM or SPP are much smaller and potentially more numerous than pollen grains and could significantly affect cloud formation in the atmosphere. However, INM and SPP are not clearly distinguished and explanations on how these materials could distribute in the atmosphere are missing. In this study we focus on birch pollen and investigate the relationship between pollen grains, INM and SPP. According to the usage of the term SPP in the medical fields we define SPP as the starch granules contained in pollen grains. We develop an extraction method to generate large quantities of SPP and show that INM are loosley attached to SPP. Further, we find that purified SPP are not ice nucleation active: after several times of washing SPP with ultrapure water the ice nucleation activity completely disappears. To our knowledge this is the first study to investigate the ice nucleation activity of isolated SPP. To study the chemical nature of the INM we use fluorescence spectroscopy. Fluorescence excitation-emission maps indicate a strong signal in the protein range (maximum around λex = 280 nm and λem = 330 nm) that correlates with the ice nucleation activity. In contrast, with purified SPP this signal is lost. We also quantify the protein concentration with the Bradford assay. The protein concentration ranges from 77.4 μg mL−1 (Highly concentrated INM) to below 2.5 μg mL−1 (purified SPP). The results indicate a linkage between ice nucleation activity and protein concentration. Even though purified SPP are not ice nucleation active they could act as carriers of INM and distribute those in the atmosphere.

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Preferential freezing avoidance localized in anthers and embryo sacs in wintering Daphne kamtschatica var. jezoensis flower buds visualized by MRI

10.22541/au.163251451.16990423/v1 ◽

2021 ◽

Author(s):

Masaya Ishikawa ◽

Hiroyuki Ide ◽

Tetsuya Tsujii ◽

Timothy Stait-Gardner ◽

Hikaru Kubo ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Cold Hardiness ◽

Ice Nucleation ◽

Ice Formation ◽

Resonance Imaging ◽

Flower Buds ◽

Male And Female ◽

Nucleation Activity ◽

Magnetic Resonance Imaging Mri ◽

Ice Nucleation Activity

To explore diversity in cold hardiness mechanisms, high resolution magnetic resonance imaging (MRI) was used to visualize freezing behaviors in wintering flower buds of Daphne kamtschatica var. jezoensis, which have no bud scales surrounding well-developed florets. MRI images showed that anthers remained stably supercooled to -14 ∼ -21°C or lower whilst most other tissues froze by -7°C. Freezing of some anthers detected in MRI images at ∼ -21°C corresponded with numerous low temperature exotherms and also with the “all-or-nothing” type of anther injuries. In ovules/pistils, only embryo sacs remained supercooled at -7°C or lower, but slowly dehydrated during further cooling. Cryomicroscopic observation revealed ice formation in the cavities of calyx tubes and pistils but detected no ice in embryo sacs or in anthers. The distribution of ice nucleation activity in floral tissues corroborated the tissue freezing behaviors. Filaments likely work as the ice blocking barrier that prevents ice intrusion from extracellularly frozen calyx tubes to connecting unfrozen anthers. Unique freezing behaviors were demonstrated in Daphne flower buds: preferential freezing avoidance in male and female gametophytes and their surrounding tissues (by stable supercooling in anthers and by supercooling with slow dehydration in embryo sacs) whilst the remaining tissues tolerate extracellular freezing.

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Acidic processing of fly ash: chemical characterization, morphology, and immersion freezing

Environmental Science Processes & Impacts ◽

10.1039/c8em00319j ◽

2018 ◽

Vol 20 (11) ◽

pp. 1581-1592 ◽

Cited By ~ 6

Author(s):

Delanie J. Losey ◽

Sarah K. Sihvonen ◽

Daniel P. Veghte ◽

Esther Chong ◽

Miriam Arak Freedman

Keyword(s):

Fly Ash ◽

Coal Combustion ◽

Chemical Characterization ◽

Ice Nucleation ◽

Immersion Freezing ◽

Nucleation Activity ◽

Ice Nucleation Activity

The ice nucleation activity of fly ash, a byproduct of coal combustion, depends on its composition.

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Subpollen particles (SPP) of birch as carriers of ice nucleating macromolecules

10.5194/egusphere-egu21-14807 ◽

2021 ◽

Author(s):

Julia Burkart ◽

Jürgen Gratzl ◽

Teresa Seifried ◽

Paul Bieber ◽

Hinrich Grothe

Keyword(s):

Protein Concentration ◽

Birch Pollen ◽

Pollen Grains ◽

Ice Nucleation ◽

Early Spring ◽

Cloud Formation ◽

Starch Granules ◽

Fluorescence Excitation ◽

Nucleation Activity ◽

Ice Nucleation Activity

Wind pollinated trees such as birch trees release large amounts of pollen to the atmosphere during their blooming season in early spring. Due to the large size of pollen (birch pollen diameter: 20-25 &#181;m) and short residence time in the atmosphere, their impact on cloud formation was believed to be negligible. However, in recent years studies have shown that ice nucleating materials, so called ice nucleating macromolecules (INM), much smaller in size can be extracted from pollen. At the same time there is evidence from medical studies that pollen can rupture under conditions of high humidity in the atmosphere and expel cytoplasmic material including starch granules, commonly referred to as subpollen particles (SPP). INM or SPP are much smaller and potentially more numerous than pollen and could significantly affect cloud formation in the atmosphere.In this study, we focus on birch pollen and investigate the relationship between pollen grains, INM and SPP. According to the usage of the term SPP in the medical field we define SPP as the starch granules contained in pollen grains. We develop an extraction method to generate large quantities of SPP and investigate their ice nucleation activity. To our knowledge, this is the first study to investigate the ice nucleation activity of isolated SPP. We show that INM are only loosely attached to SPP and that purified SPP are not ice nucleation active: after several times of washing SPP with ultrapure water the ice nucleation activity completely disappears. In addition, we study the chemical nature of the INM with fluorescence spectroscopy and quantify the protein concentration with the Bradford assay. Fluorescence excitation-emission maps indicate a strong signal in the protein range (maximum around &#955;ex = 280 nm and &#955;em = 330 nm) that correlates with the ice nucleation activity. In contrast, with purified SPP this signal is lost. The protein concentration ranges from 77.4 &#956;g mL-1 for highly concentrated INM to below 2.5 &#956;g mL-1 for purified SPP. The results thereby indicate a linkage between ice nucleation activity and protein concentration. Purified SPP are not ice nucleation active but could, however, act as carriers of INM and distribute those in the atmosphere.

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A Link between the Ice Nucleation Activity of Sea Spray Aerosol and the Biogeochemistry of Seawater

10.5194/acp-2020-416 ◽

2020 ◽

Cited By ~ 1

Author(s):

Martin J. Wolf ◽

Megan Goodell ◽

Eric Dong ◽

Lilian A. Dove ◽

Cuiqi Zhang ◽

...

Keyword(s):

North Pacific Ocean ◽

Ice Nucleation ◽

Cloud Formation ◽

Subsurface Water ◽

Sea Spray ◽

Subsurface Waters ◽

Sea Spray Aerosol ◽

Nucleation Activity ◽

Florida Straits ◽

Ice Nucleation Activity

Abstract. Emissions of ice nucleating particles from sea spray can impact climate and precipitation by changing cloud formation, precipitation, and albedo. However, the relationship between seawater biogeochemistry and the ice nucleation activity of sea spray aerosols remains unclarified. Here, we demonstrate a link between the biological productivity in seawater and the ice nucleation activity of sea spray aerosol under conditions relevant to cirrus and mixed-phase cloud formation. We show for the first time that aerosol generated from both subsurface and microlayer seawater from the highly productive Eastern Tropical North Pacific Ocean are effective ice nucleating particles in the deposition and immersion freezing modes. Jet droplets aerosolized from the subsurface waters of highly productive regions may therefore be an unrealized source of effective INPs. In contrast, the subsurface water from the less productive Florida Straits produced less effective immersion mode INPs and ineffective depositional mode INPs. These results indicate that the regional biogeochemistry of seawater can strongly affect the ice nucleation activity of sea spray aerosol.

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Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-1785-2018 ◽

2018 ◽

Vol 18 (3) ◽

pp. 1785-1804 ◽

Cited By ~ 10

Author(s):

Ayumi Iwata ◽

Atsushi Matsuki

Keyword(s):

Atmospheric Aerosols ◽

Mineral Dust ◽

Aerosol Particles ◽

Ice Nucleation ◽

Asian Dust ◽

Particle Mixing ◽

Active Particles ◽

Nucleation Activity ◽

Mixing States ◽

Ice Nucleation Activity

Abstract. In order to better characterize ice nucleating (IN) aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed-phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles) were compared with actual aerosol particles collected from the west coast of Japan (the city of Kanazawa) during Asian dust events in February and April 2016. Following droplet activation by particles deposited on a hydrophobic Si (silicon) wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to −30 ∘C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by atomic force microscopy (AFM), micro-Raman spectroscopy, and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (e.g., −22.2 to −24.2 ∘C with K-feldspar) than the homogeneous freezing temperature (−36.5 ∘C). Meanwhile, most of the IN active atmospheric particles formed ice below −28 ∘C, i.e., at lower temperatures than the standard mineral dust samples of pure components. The most abundant IN active particles above −30 ∘C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components). Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral dust particles. Also, relatively pure or fresh calcite, Ca(NO3)2, and (NH4)2SO4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

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Characterization of individual ice nuclei by the single droplet freezing method: a case study in the Asian dust outflow region

10.5194/acp-2017-301 ◽

2017 ◽

Author(s):

Ayumi Iwata ◽

Atsushi Matsuki

Keyword(s):

Atmospheric Aerosols ◽

Mineral Dust ◽

Aerosol Particles ◽

Ice Nucleation ◽

Asian Dust ◽

Particle Mixing ◽

Active Particles ◽

Nucleation Activity ◽

Mixing States ◽

Ice Nucleation Activity

Abstract. In order to better characterize ice-nucleating (IN) aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles) were compared with actual aerosol particles collected from the west coast of Japan (Kanazawa City) during Asian dust events in February and April 2016. Following droplet activation by particles deposited 5 on a hydrophobic Si wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to −30 °C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by Atomic Force Microscopy (AFM), micro-Raman spectroscopy, and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray spectroscopy (EDX). Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (−25.7 °C) than the homogeneous freezing temperature (−36.5 °C). Meanwhile, most of the IN active atmospheric particles formed ice below −28 °C and were found to be IN active, but slower than the standard mineral dust samples of pure components. The most abundant IN active particles above −30 °C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components). Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral dust particles. Also, relatively pure or fresh calcite, Ca(NO3)2, and (NH4)2SO4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

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IMPROVING ICE FORMATION BY ADDITIVE FOR COLD ENERGY STORAGE

International Journal of Air-Conditioning and Refrigeration ◽

10.1142/s2010132514500126 ◽

2014 ◽

Vol 22 (03) ◽

pp. 1450012 ◽

Cited By ~ 2

Author(s):

JIN HU ◽

OSMANN SARI ◽

CYRIL MAHMED

Keyword(s):

Heat Release ◽

Pseudomonas Syringae ◽

Freezing Temperature ◽

Ice Nucleation ◽

Ice Formation ◽

Nucleation Agent ◽

Cold Energy ◽

Nucleation Activity ◽

Effective Use ◽

Ice Nucleation Activity

Ice storage is one technique for effective use of thermal energy. Application of bionucleant (a protein from the bacterium Pseudomonas syringae) as a snow inducer in ski field has shown great potential to enhance the quantity of snow and increase freezing temperature. In this study, differential scanning calorimeter (DSC) and lab-built ice formation reactor were employed to study experimentally the heterogeneous ice nucleation under super-cooled conditions at different dissolved bionucleant concentrations. It was found the degree of supercooling is reduced by addition of bionucleant. However, ice nucleation-activity of bionucleant will drop down when bionucleant solution is saturated/supersaturated. In our DSC measured heat release study, when bionucleant acts as ice nucleation agent in aqueous solution, prior to reaching its saturation/supersaturation, there is an increase in latent heat release during freezing/melting as the amount of dissolved bionucleant increases. In another test, the supercooling does not occur in 0.5% bionucleant solution, it began to freeze around 0°C. Our results suggest that, the addition of bionucleant may help induce ice nucleation and increase freezing temperature thereby reduces the energy consumption of ice formation for cold storage.

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