scholarly journals Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars

2019 ◽  
Author(s):  
André Welti ◽  
Ulrike Lohmann ◽  
Zamin A. Kanji
Keyword(s):  
Trace Elements ◽  
Elemental Composition ◽  
Ice Nucleation ◽  
Cloud Properties ◽  
Ability To Act ◽  
Mineralogical Characteristics ◽  
Trace Elemental ◽  
Mineral Dusts ◽  
Immersion Freezing ◽  
Ice Nucleation Activity

Abstract. The relation between the mineralogical characteristics of size selected feldspar particles from 50–800 nm and their ability to act as ice nucleating particles (INPs) in the immersion mode is presented. Five polymorph members of K-feldspar (two microclines, orthoclase, adularia and sanidine) and four Na/Ca- rich feldspar samples (three labradorites and a pericline sample) are tested. Microcline was found to be the most active INP in the immersion mode consistent with previous findings. Samples are selected for their differences in typical feldspar properties such as crystal structure, bulk and trace elemental composition and ordering of the crystal lattice. The mentioned properties are related to the temperature of feldspar crystallization from the melt rocks during formation. Properties characteristic for low temperature feldspar formation coincide with an increased ability to nucleate ice. Ice nucleation is most efficient on the crystallographic ordered, triclinic K-feldspar species microcline, while the intermediate and disordered, monoclinic K-feldspar polymorphs orthoclase and sanidine nucleate ice at lower temperatures. The ice nucleation ability of disordered, triclinic Na/Ca-feldspar is comparable to disordered K-feldspar. The conditions of feldspar rock formation also leave a chemical fingerprint with varying abundance of trace elements in the samples. X-ray fluorescence spectroscopy analysis to determine metal oxide and trace elemental composition of the feldspar samples revealed a correlation with median freezing temperatures (T50) of the K-feldspar samples allowing to sort them for their ice nucleation efficiency according to the abundance of specific trace elements. A pronounced size dependence of ice nucleation activity for the feldspar samples is observed, which also depends on mineralogical characteristics. In particular, microcline exhibited immersion freezing even for 50 nm particles which is unique for heterogeneous ice nucleation of mineral dusts. This suggests that small microcline particles that are susceptible to long-range transport can affect cloud properties via immersion freezing far away from the source. The measurements generally imply that temperatures at which feldspars can affect cloud glaciation depends on the transported particle size.

scholarly journals Ice nucleation properties of K-feldspar polymorphs and plagioclase feldspars

2019 ◽  
Vol 19 (16) ◽  
pp. 10901-10918 ◽  
Author(s):  
André Welti ◽  
Ulrike Lohmann ◽  
Zamin A. Kanji
Keyword(s):  
Trace Elements ◽  
Elemental Composition ◽  
Size Dependence ◽  
Ice Nucleation ◽  
Cloud Properties ◽  
Ability To Act ◽  
Metal Abundance ◽  
Trace Elemental ◽  
Immersion Freezing ◽  
Ice Nucleation Activity

Abstract. The relation between the mineralogical characteristics of size-selected feldspar particles from 50 to 800 nm and their ability to act as ice-nucleating particles (INPs) in the immersion mode is presented. Five polymorph members of K-feldspar (two microclines, orthoclase, adularia and sanidine) and four plagioclase samples (three labradorites and a pericline sample) are tested. Microcline was found to be the most active INP in the immersion mode consistent with previous findings. Samples were selected for their differences in typical feldspar properties such as crystal structure, bulk and trace elemental composition, and ordering of the crystal lattice. The properties mentioned are related to the temperature of feldspar crystallization from the magma during formation. Properties characteristic of low-temperature feldspar formation coincide with an increased ability to nucleate ice. Amongst the samples investigated, ice nucleation is most efficient on the crystallographically ordered, triclinic K-feldspar species microcline, while the intermediate and disordered monoclinic K-feldspar polymorphs orthoclase and sanidine nucleate ice at lower temperatures. The ice nucleation ability of disordered triclinic Na∕Ca-feldspar is comparable to disordered K-feldspar. The conditions of feldspar rock formation also leave a chemical fingerprint with varying abundance of trace elements in the samples. X-ray fluorescence spectroscopy analysis was conducted to determine metal oxide and trace elemental composition of the feldspar samples. The analysis revealed a correlation of trace metal abundance with median freezing temperatures (T50) of the K-feldspar samples allowing us to sort them for their ice nucleation efficiency according to the abundance of specific trace elements. A pronounced size dependence of ice nucleation activity for the feldspar samples is observed, with the activity of smaller-sized particles scaling with surface area or being even higher compared to larger particles. The size dependence varies for different feldspar samples. In particular, microcline exhibited immersion freezing even for 50 nm particles which is unique for heterogeneous ice nucleation of mineral dusts. This suggests that small microcline particles that are susceptible to long-range transport can affect cloud properties via immersion freezing far away from the source. The measurements generally imply that temperatures at which feldspars can affect cloud glaciation depend on the transported particle size in addition to the abundance of these particles.

Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO

2021 ◽  
Vol 23 (5) ◽  
pp. 3565-3573
Author(s):  
Esther Chong ◽  
Katherine E. Marak ◽  
Yang Li ◽  
Miriam Arak Freedman
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Ice Nucleation ◽  
Mechanical Processing ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

FeO has enhanced ice nucleation activity due to functional groups that are exposed upon mechanical processing.

Towards a molecular-based parameterization of the ice nucleation activity of biological macromolecules and its implications for aerosol-cloud interactions

2021 ◽  
Author(s):  
Minghui Zhang ◽  
Amina Khaled ◽  
Pierre Amato ◽  
Anne-Marie Delort ◽  
Barbara Ervens
Keyword(s):  
Fungal Spores ◽  
Chemical Properties ◽  
Active Surface ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Biological Macromolecules ◽  
Cloud Properties ◽  
Nucleation Activity ◽  
Mixed Phase Clouds ◽  
Ice Nucleation Activity

<p>Primary biological aerosol particles (PBAPs) play an important role in mixed-phase clouds as they nucleate ice even at temperatures of T > -10 °C. Current parameterizations of PBAP ice nucleation are based on ice nucleation active surface site (INAS) densities that are derived from freezing experiments. However, only a small fraction of the PBAP surface is responsible for their ice nucleation activity, such as proteins of bacteria cells, fungal spores, pollen polysaccharides and other (unidentified) macromolecules. Based on literature data, we refine the INAS density parameterizations by further parameters:</p><p>1) We demonstrate that the ice nucleation activity of such individual macromolecules is much higher than that of PBAPs. It can be shown that INAS of PBAPs can be scaled by the surface fraction of these ice-nucleating molecules.</p><p>2) Previous studies suggested that ice nucleation activity tends to be higher for larger macromolecules and their aggregates. We show that these trends hold true for various groups of macromolecules that comprise PBAPs.</p><p>Based on these trends, we suggest a more refined parameterization for ice-nucleating macromolecules in different types of PBAPs and even for different species of bacteria, fungi, and pollen. This new parameterization can be considered a step towards a molecular-based approach to predict the ice nucleation activity of the macromolecules in PBAPs based on their biological and chemical properties.</p><p>We implement both the traditional INAS parameterization for complete PBAPs and our parameterization for individual molecules in an adiabatic cloud parcel model. The extent will be discussed to which the two parameterizations result in different cloud properties of mixed-phase clouds.</p>

scholarly journals Deposition and immersion-mode nucleation of ice by three distinct samples of volcanic ash

2015 ◽  
Vol 15 (13) ◽  
pp. 7523-7536 ◽  
Author(s):  
G. P. Schill ◽  
K. Genareau ◽  
M. A. Tolbert
Keyword(s):  
Volcanic Ash ◽  
Mineral Dust ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Silica Content ◽  
Ice Nucleation ◽  
Ice Nuclei ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Ice nucleation of volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui eruption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225 to 235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited appreciable heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

Influence of organic and biogenic substances on the ice nucleation properties of mineral dust particles

2020 ◽  
Author(s):  
Kristian Klumpp ◽  
Claudia Marcolli ◽  
Thomas Peter
Keyword(s):  
Amino Acids ◽  
Organic Acids ◽  
Mineral Dust ◽  
Particle Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Biogenic Substances ◽  
Immersion Freezing ◽  
Mixed Phase Clouds ◽  
Ice Nucleation Activity

<p>The formation of ice in mixed phase clouds occurs in the presence of aerosol particles with the ability to nucleate ice on their surface. These ice-nucleating particles (INPs) represent usually a small fraction of particles in an atmospheric aerosol. One of the main particle types which act as INPs are mineral dust particles. Among other factors, the accumulation of semivolatile substances on the particle surface can alter the ice nucleation properties of such particles.</p><p>In recent immersion freezing experiments, we investigated the influence of organic acids, amino acids and polyols on the highly ice nucleation active K-feldspar microcline. Microcline dust was suspended in solutions of the above-mentioned substances and frozen in a differential scanning calorimeter (DSC). These experiments give us insight into the ice nucleation characteristics of the particles in the presence of the tested organic and biogenic substances. Our measurements show an overall decrease in ice nucleation activity of microcline in the presence of organic acids and amino acids. <br><br></p>

scholarly journals Ice nucleation properties of fine ash particles from the Eyjafjallajökull eruption in April 2010

2011 ◽  
Vol 11 (6) ◽  
pp. 17665-17698 ◽  
Author(s):  
I. Steinke ◽  
O. Möhler ◽  
A. Kiselev ◽  
M. Niemand ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Active Surface ◽  
Ice Nucleation ◽  
Saharan Dust ◽  
Surface Site ◽  
Ice Nuclei ◽  
Active Surface Site ◽  
Mineral Dusts ◽  
Immersion Freezing ◽  
Ice Fraction

Abstract. During the eruption of the Eyjafjallajökull volcano in the south of Iceland in April/May 2010, about 40 Tg of ash mass were emitted into the atmosphere. However, it was unclear whether volcanic ash particles with d < 10 μm facilitate the glaciation of clouds. Thus, ice nucleation properties of volcanic ash particles were investigated in AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber experiments simulating atmospherically relevant conditions. The ash sample that was used for our experiments had been collected at a distance of 58 km from the Eyjafjallajökull during the eruption period in April 2010. The temperature range covered by our ice nucleation experiments extended from 219 to 264 K, and both ice nucleation via immersion freezing and deposition nucleation could be observed. Immersion freezing was first observed at 252 K, whereas the deposition nucleation onset lay at 242 K and RHice = 126 %. About 0.1 % of the volcanic ash particles were active as immersion freezing nuclei at a temperature of 249 K. For deposition nucleation, an ice fraction of 0.1 % was observed at around 233 K and RHice = 116 %. Taking ice-active surface site densities as a measure for the ice nucleation efficiency, volcanic ash particles are similarly efficient ice nuclei in immersion freezing mode (ns, imm ~ 109 m−2 at 247 K) compared to certain mineral dusts. For deposition nucleation, the observed ice-active surface site densities ns, dep were found to be 1011 m−2 at 224 K and RHice = 116 %. Thus, volcanic ash particles initiate deposition nucleation more efficiently than Asian and Saharan dust but appear to be poorer ice nuclei than ATD particles. Based on the experimental data, we have derived ice-active surface site densities as a function of temperature for immersion freezing and of relative humidity over ice and temperature for deposition nucleation.

scholarly journals The contribution of fungal spores and bacteria to regional and global aerosol number and ice nucleation immersion freezing rates

2013 ◽  
Vol 13 (12) ◽  
pp. 32459-32481 ◽  
Author(s):  
D. V. Spracklen ◽  
C. L. Heald
Keyword(s):  
Cloud Condensation Nuclei ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Model Studies ◽  
Modelling Studies ◽  
Climate Interactions ◽  
Immersion Freezing ◽  
Simulated Surface ◽  
Mixed Phase Clouds ◽  
Ice Nucleation Activity

Abstract. Primary biological aerosol particles (PBAP) may play an important role in aerosol–climate interactions, in particular through affecting ice formation in mixed phase clouds. However, the role of PBAP is poorly understood because the sources and distribution of PBAP in the atmosphere are not well quantified. Here we include emissions of fungal spores and bacteria in a global aerosol microphysics model and explore their contribution to concentrations of supermicron particle number, cloud condensation nuclei (CCN) and immersion freezing rates. Simulated surface annual mean concentrations of fungal spores are ~2.5 × 104 m−3 over continental midlatiudes and 1 × 105 m−3 over tropical forests. Simulated surface concentrations of bacteria are 2.5 × 104 m−3 over most continental regions and 5 × 104 m−3 over grasslands of central Asia and North America. These simulated surface number concentrations of fungal spores and bacteria are broadly in agreement with the limited available observations. We find that fungal spores and bacteria contribute 8% and 5% respectively to simulated continental surface mean supermicron number concentrations, but have very limited impact on CCN concentrations, altering regional concentrations by less than 1%. In agreement with previous global modelling studies we find that fungal spores and bacteria contribute very little (3 × 10−3 % even when we assume upper limits for ice nucleation activity) to global average immersion freezing ice nucleation rates, which are dominated by soot and dust. However, at lower altitudes (400 hPa to 600 hPa), where warmer temperatures mean that soot and dust may not nucleate ice, we find that PBAP controls the immersion freezing ice nucleation rate. This demonstrates that PBAP can be of regional importance for IN formation, in agreement with case study observations but in contrast to recent global model studies that have concluded PBAP are unimportant as ice nuclei.

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

2018 ◽  
Vol 20 (11) ◽  
pp. 1581-1592 ◽  
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.

scholarly journals Comparing contact and immersion freezing from continuous flow diffusion chambers

2016 ◽  
Author(s):  
Baban Nagare ◽  
Claudia Marcolli ◽  
André Welti ◽  
Olaf Stetzer ◽  
Ulrike Lohmann
Keyword(s):  
Residence Time ◽  
Continuous Flow ◽  
Diffusion Chamber ◽  
Ice Nucleation ◽  
Freezing Process ◽  
Electrical Mobility ◽  
Cloud Droplets ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Ice nucleating particles (INPs) in the atmosphere are responsible for glaciating cloud droplets between 237 K and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data was obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH) using 80 μm diameter droplets which can interact with INPs for residence times of 2 s and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter ATD and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm−3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm−3 for AgI. For concentrations < 5000 cm−3, the droplets collect only one particle on average during their time in the chamber. For ATD and kaolinite particles, contact freezing efficiencies at 2 s residence time were smaller than at 4 s, which is in disagreement with a collisional contact freezing process but in accordance with contact freezing insideout or immersion freezing. For best comparison with contact freezing results, immersion freezing experiments of the same INPs were performed with the continuous flow diffusion chamber IMCA/ZINC for 3 s residence time. In IMCA/ZINC, each INP is activated into a droplet in IMCA and provides its surface for ice nucleation in the ZINC chamber. The comparison of contact and immersion freezing results did not confirm a general enhancement of freezing efficiency for contact compared with immersion freezing experiments. For AgI particles the onset of heterogeneous freezing in CLINCH was even shifted to lower temperatures compared with IMCA/ZINC. For ATD, freezing efficiencies for contact and immersion freezing experiments were similar. For kaolinite particles, contact freezing became detectable at higher temperatures than immersion freezing. Using contact angle information between water and the INP, it is discussed how the position of the INP in or on the droplets may influence its ice nucleation activity.

scholarly journals A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

2015 ◽  
Vol 15 (5) ◽  
pp. 2489-2518 ◽  
Author(s):  
N. Hiranuma ◽  
S. Augustin-Bauditz ◽  
H. Bingemer ◽  
C. Budke ◽  
J. Curtius ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Surface Area ◽  
Mineral Dust ◽  
Measurement Techniques ◽  
Ice Nucleation ◽  
Measurement Methods ◽  
Dust Particles ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Immersion freezing is the most relevant heterogeneous ice nucleation mechanism through which ice crystals are formed in mixed-phase clouds. In recent years, an increasing number of laboratory experiments utilizing a variety of instruments have examined immersion freezing activity of atmospherically relevant ice-nucleating particles. However, an intercomparison of these laboratory results is a difficult task because investigators have used different ice nucleation (IN) measurement methods to produce these results. A remaining challenge is to explore the sensitivity and accuracy of these techniques and to understand how the IN results are potentially influenced or biased by experimental parameters associated with these techniques. Within the framework of INUIT (Ice Nuclei Research Unit), we distributed an illite-rich sample (illite NX) as a representative surrogate for atmospheric mineral dust particles to investigators to perform immersion freezing experiments using different IN measurement methods and to obtain IN data as a function of particle concentration, temperature (T), cooling rate and nucleation time. A total of 17 measurement methods were involved in the data intercomparison. Experiments with seven instruments started with the test sample pre-suspended in water before cooling, while 10 other instruments employed water vapor condensation onto dry-dispersed particles followed by immersion freezing. The resulting comprehensive immersion freezing data set was evaluated using the ice nucleation active surface-site density, ns, to develop a representative ns(T) spectrum that spans a wide temperature range (−37 °C < T < −11 °C) and covers 9 orders of magnitude in ns. In general, the 17 immersion freezing measurement techniques deviate, within a range of about 8 °C in terms of temperature, by 3 orders of magnitude with respect to ns. In addition, we show evidence that the immersion freezing efficiency expressed in ns of illite NX particles is relatively independent of droplet size, particle mass in suspension, particle size and cooling rate during freezing. A strong temperature dependence and weak time and size dependence of the immersion freezing efficiency of illite-rich clay mineral particles enabled the ns parameterization solely as a function of temperature. We also characterized the ns(T) spectra and identified a section with a steep slope between −20 and −27 °C, where a large fraction of active sites of our test dust may trigger immersion freezing. This slope was followed by a region with a gentler slope at temperatures below −27 °C. While the agreement between different instruments was reasonable below ~ −27 °C, there seemed to be a different trend in the temperature-dependent ice nucleation activity from the suspension and dry-dispersed particle measurements for this mineral dust, in particular at higher temperatures. For instance, the ice nucleation activity expressed in ns was smaller for the average of the wet suspended samples and higher for the average of the dry-dispersed aerosol samples between about −27 and −18 °C. Only instruments making measurements with wet suspended samples were able to measure ice nucleation above −18 °C. A possible explanation for the deviation between −27 and −18 °C is discussed. Multiple exponential distribution fits in both linear and log space for both specific surface area-based ns(T) and geometric surface area-based ns(T) are provided. These new fits, constrained by using identical reference samples, will help to compare IN measurement methods that are not included in the present study and IN data from future IN instruments.

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