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A Particle Surface Area Based Formulation Of Heterogeneous Ice Nucleation By Mineral Dust Aerosols
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Book Synopsis A Particle-Surface-Area-Based Formulation of Heterogeneous Ice Nucleation by Mineral Dust Aerosols by : Monika Niemand
Download or read book A Particle-Surface-Area-Based Formulation of Heterogeneous Ice Nucleation by Mineral Dust Aerosols written by Monika Niemand and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laboratory Studies of Deposition Mode Heterogeneous Ice Nucleation by : Zaminhussein Abdulali Kanji
Download or read book Laboratory Studies of Deposition Mode Heterogeneous Ice Nucleation written by Zaminhussein Abdulali Kanji and published by . This book was released on 2009 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: The indirect aerosol effect contributes to major uncertainties in determining the radiation budget of the earth. A large uncertainty is due to the formation of ice clouds onto natural or anthropogenic aerosols. Field studies have shown that mineral type particles are often associated with ice crystals in the mid-upper troposphere and given the long residence time in the atmosphere of dust particles (∼2 weeks in the absence of precipitation), their contribution to ice formation processes is not fully defined.It was concluded that there is no single value for the onset of ice formation in the atmosphere via deposition freezing. The associated contact angles show that there is a distribution of active sites on IN and that not all active sites have the same affinity for initiation of ice formation even within the same aerosol type. This work provides evidence that deposition mode nucleation can be an alternate pathway to homogeneous nucleation when mineral aerosols are present in the troposphere since the high T-low RH conditions required for deposition mode nucleation are more easily encountered in the atmosphere than the low T-high RH required for homogeneous nucleation.In order to probe ice formation onto natural mineral dust in a setting where it could be suspended as aerosol, a new continuous flow diffusion chamber (CFDC) was built. This allowed investigations of the effects of total aerosol surface area and particle size. The CFDC was also used in an international inter-comparison of ice nucleation instrumentation to compare efficiencies of soot, biological aerosol (bacteria) and samples of natural desert dusts from different regions of the world. The laboratory observations were parameterized using nucleation rates (Jhet) and contact angles (theta) as described by classical nucleation theory.For both this experimental technique and a static one developed during the candidate's Masters degree, mineral dust particulate proved to be the most efficient ice nuclei (IN) activating at RH with respect to ice (RH i) as low as 105% at T=233 K. The efficiency varied with particle size and aerosol surface area (SA). Large particles or higher SA activated at lower RHi than small particles or lower SA. The static chamber was sensitive to the first ice event out of a large SA and therefore gave true onset RHi, which was lower than the onset defined by the CFDC studies, which was not sensitive to a single ice event. In addition the static chamber used a broader size range of particulate matter, including super micron particles while the CFDC particles sizes were restricted to below 0.5 microm. Soot and organic coated dust particles were inefficient IN compared to pure dust. Soot aerosols showed some efficiency at T
Book Synopsis Ice Nucleation Effects of Soot and Mineral Dust Aerosol Particles by : Valerie Alstadt
Download or read book Ice Nucleation Effects of Soot and Mineral Dust Aerosol Particles written by Valerie Alstadt and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The composition and properties of aerosol particles present in the atmosphere have broad implications for both climate and human health. Aerosol particles interact with water and form cloud condensation nuclei or ice nuclei; however, the effect of these interactions on climate are not well understood. Additionally, the heterogeneous chemistry of aerosol particles can affect atmospheric particle composition and ice nucleation activity. Particle size and local aerosol composition also have important implications for human health. Of particular interest are mineral dust particles as these particles may undergo long range transport after entering the atmosphere through desert winds. These particles can interact with other atmospheric pollutants, which may alter their surface properties. We investigated the adsorption of one such pollutant, acetic acid, on the surface of the mineral kaolinite before and after the addition of water vapor using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). To determine the conformation of the resulting adsorbates on the surface, we used molecular modeling to determine the theoretical frequencies of possible surface conformations. This research determined that the type of adsorbate on the surface of the treated particles varied with the addition of water as some conformations were more energetically stable in the presence of water than others.Further work focused on water adsorption on the nanoscale and the energetics of water desorption. We studied the effects of surface defects on water adsorption on the surface of sodium chloride using Atomic Force Microscopy (AFM) and Temperature Program Desorption Spectroscopy (TPDS). This research provided insight into the energetics of how water binds to sodium chloride and how water binds onto water layers at cold temperatures. As the surface properties and composition of particles with good ice nucleation activity in the atmosphere are unclear, we also studied the immersion freezing activity of multi-walled carbon nanotubes in order to determine whether ice nucleation occurred on the outer surface, inner pore, or edge of the carbon nanotube. Using additional characterization methods, we determined that freezing occurred inside the nanotube and that freezing began at different temperatures depending on the size of the inner diameter. This research provided insight into how soot and the spherules that comprise soot could be an effective ice nucleus depending on size. On the local level, we have studied the changes in atmospheric particle composition in University Park, PA before and after local power plants converted from coal to natural gas consumption. Particle measurements were taken fourteen times in a two-year period and Transmission Electron Microscopy (TEM) was performed in order to determine how particle composition changed and whether or not the number of fractal particles changed. The long-term aim of this study was to provide specific information on the local composition of PM2.5 particles.
Book Synopsis Mixed-Phase Clouds by : Constantin Andronache
Download or read book Mixed-Phase Clouds written by Constantin Andronache and published by Elsevier. This book was released on 2017-09-28 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed-Phase Clouds: Observations and Modeling presents advanced research topics on mixed-phase clouds. As the societal impacts of extreme weather and its forecasting grow, there is a continuous need to refine atmospheric observations, techniques and numerical models. Understanding the role of clouds in the atmosphere is increasingly vital for current applications, such as prediction and prevention of aircraft icing, weather modification, and the assessment of the effects of cloud phase partition in climate models. This book provides the essential information needed to address these problems with a focus on current observations, simulations and applications. - Provides in-depth knowledge and simulation of mixed-phase clouds over many regions of Earth, explaining their role in weather and climate - Features current research examples and case studies, including those on advanced research methods from authors with experience in both academia and the industry - Discusses the latest advances in this subject area, providing the reader with access to best practices for remote sensing and numerical modeling
Book Synopsis Chemical Characterization of Heterogeneous Ice Nuclei in the Atmosphere by : Sarah Sihvonen
Download or read book Chemical Characterization of Heterogeneous Ice Nuclei in the Atmosphere written by Sarah Sihvonen and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol particles impact the climate by serving as the seeds to form water droplets and ice to form clouds. However, these aerosol-cloud interactions are the least understood aspect of our understanding of the climate system. Mineral dust aerosol is the largest global source of ice nucleating particles. During atmospheric transport, mineral dust can be exposed to sulfuric acid, which has been shown to decrease the ice nucleation activity of these particles. Many explanations for this observation, such as chemical changes to the surface or product formation that blocks active sites, have been suggested. Our research focused on building a molecular picture of these surfaces to understand why sulfuric acid exposure reduces the ice nucleation activity of clay minerals such as kaolinite. We performed studies using X-ray diffraction and solid state NMR that investigate the changes that clay minerals undergo as a result of acid exposure. We are the first to show that the formation of a product on the surface of kaolinite was responsible for the decreased ice nucleation activity, not surface changes to the mineral itself. We continued to study aerosol-cloud interactions by using parcel models that explore the impact of ice growth surface kinetics on the competition between heterogeneous and homogeneous ice nucleation in clouds. We found that impaired growth of ice favors homogeneous freezing. The parcel models will be expanded to include our work on clay minerals to explore the impact of chemical aging of ice nuclei on overall cloud properties. We also studied the effect of acidic-processing on coal fly ash samples. Coal fly ash has been found to have a similar atmospheric impact as mineral dust, but is studied to a lesser extent. Like mineral dust, coal fly ash can serve as a source of bioavailable iron to phytoplankton in nutrient limited regions of the ocean. Fly ash has also been found to serve as an ice nucleating material. We performed aqueous sulfuric acid-treatment on fly ash samples representative of the types produced in the United States. We found that a soluble salt, gypsum (hydrated calcium sulfate), formed on three out of four samples. The most iron rich sample did not react with sulfuric acid. However, acidic-processing was shown to increase the amount of soluble iron which has implications for the biogeochemical cycle. These results also demonstrate that further work investigating these fly ash systems is warranted. In addition to our work on ice nucleation, we constructed a photoacoustic spectrometer to measure the absorbance of aerosol particles to study the optical properties of atmospheric aerosol. These measurements will aid in understanding the interactions of aerosol particles with light and the radiative balance of the planet.
Book Synopsis Microphysics of Clouds and Precipitation by : H.R. Pruppacher
Download or read book Microphysics of Clouds and Precipitation written by H.R. Pruppacher and published by Springer Science & Business Media. This book was released on 2010-06-25 with total page 975 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cloud physics has achieved such a voluminous literature over the past few decades that a significant quantitative study of the entire field would prove unwieldy. This book concentrates on one major aspect: cloud microphysics, which involves the processes that lead to the formation of individual cloud and precipitation particles. Common practice has shown that one may distinguish among the following addi tional major aspects: cloud dynamics, which is concerned with the physics respon sible for the macroscopic features of clouds; cloud electricity, which deals with the electrical structure of clouds and the electrification processes of cloud and precipi tation particles; and cloud optics and radar meteorology, which describe the effects of electromagnetic waves interacting with clouds and precipitation. Another field intimately related to cloud physics is atmospheric chemistry, which involves the chemical composition ofthe atmosphere and the life cycle and characteristics of its gaseous and particulate constituents. In view of the natural interdependence of the various aspects of cloud physics, the subject of microphysics cannot be discussed very meaningfully out of context. Therefore, we have found it necessary to touch briefly upon a few simple and basic concepts of cloud dynamics and thermodynamics, and to provide an account of the major characteristics of atmospheric aerosol particles. We have also included a separate chapter on some of the effects of electric fields and charges on the precipitation-forming processes.
Book Synopsis Surface Property Impacts on Heterogeneous Ice Nucleation of Engineered Materials by : Katherine Marak
Download or read book Surface Property Impacts on Heterogeneous Ice Nucleation of Engineered Materials written by Katherine Marak and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol particles can facilitate heterogenous ice formation in the troposphere and stratosphere by acting as ice nuclei, modulating cloud formation/dissipation, precipitation, and their microphysical properties. Heterogeneous ice nucleation is driven by ice embryo formation on the particle surface, which can be influenced by features of the surface such as crystallinity, surface structure, lattice structure, defects, and functional groups. Probing for deeper understanding of what surface features have the greatest impact on heterogeneous freezing is significant and can be done with synthetic and modified materials. To characterize the effect of crystallinity, pores, and surface functional groups towards ice nucleation, samples of comparable silica systems, specifically, quartz, ordered and non-ordered porous amorphous silica samples with a range of pore sizes (2-11 nm), and non-porous functionalized silica spheres were used as models for mineral dust aerosol particles (Chapter 2). The results suggest that crystallinity has a larger effect than porosity on ice nucleation activity, as all of the porous silica samples investigated had lower onset freezing temperatures and lower ice nucleation activities than quartz. Our findings also suggest that pores alone are not sufficient to serve as effective active sites, and need some additional chemical or physical property, like crystallinity, to nucleate ice in immersion mode freezing. The addition of a low density of organic functional groups to non-porous samples showed little enhancement compared to the inherent nucleation activity of silica with native surface hydroxyl groups. The density of functional groups investigated in this work suggests that a different arrangement of surface groups may be needed for enhanced immersion mode ice nucleation activity. In summary, crystallinity dictates the ice nucleation activity of silica samples rather than porosity or low-density surface functional groups. Silver and gold nanoparticles with thiol ligands of different functionalities (alkane, carboxylic acid and alcohol) were investigated for immersion ice nucleation activities (Chapter 3). The alcohol ligand nanoparticles of both silver and gold had significantly higher activities than the alkane thiol ligand, with a 4.5 oC and 10.7 oC difference in median freezing temperature respectively. Silver nanoparticles capped with thiol alcohol ligands were also tested for aggregation and oxidative stability. The silver nanoparticles are oxidatively stable for at least 2 years. We have also shown that aggregates of nanoparticles have likely caused the activity for all of the silver and gold samples, as ice nucleation activity strongly diminished when large aggregates (>200 nm) were filtered from solution. Investigating the ice nucleation activity of synthetic ZSM-5 samples with varying Si:Al helps to clarify ice nucleation activity of natural mineral dust samples, which are often aluminosilicate based materials (Chapter 4). Additionally, ammonium is a very common cation in the atmosphere, and its effects on ice nucleation activity are still being studied. Ice nucleation temperature increases with increasing Al content. Additionally, when ammonium is the cation that is strongly adsorbed to the surface and in pores, initial freezing temperatures are reduced by up to 6 oC. Seeing a drastic decrease in ice nucleation activity in the presence of ammonium, suggests that the cation can interact with the surface to block active sites. In addition to ice nucleation, dust samples can affect human health. The goal of Chapter 5 is to present risk assessments for trace element concentrations in PM10 dusts from simulated road material and township roads with/without oil and gas produced water brine (O&GPWB) treatment. PM10 trace metal quantification was conducted by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and compared to values from EDS analysis on PM2.5. Among adults, PM10 inhalation lifetime cancer risks (CRinh range: 2.39E+01 to 7.73E+01) and hazard quotients for As, Ni and Pb exposure were elevated for O&GPWB, SFSR and RRA. Cumulative Pb dose for the O&GPWB-treated roads was 71 ng/kg by age 21, compared with 37 ng/kg for non-treated roads. Our results may be consistent with elevated blood lead (Pb) concentrations above state averages in this rural O&G producing region.
Book Synopsis Nucleation of Water by : Ari Laaksonen
Download or read book Nucleation of Water written by Ari Laaksonen and published by Elsevier. This book was released on 2021-11-25 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleation of Water: From Fundamental Science to Atmospheric and Additional Applications provides a comprehensive accounting of the current state-of-the-art regarding the nucleation of water. It covers vapor-liquid, liquid-vapor, liquid-ice and vapor-ice transitions and describes basic kinetic and thermodynamic concepts in a manner understandable to researchers working on specific applications. The main focus of the book lies in atmospheric phenomena, but it also describes engineering and biological applications. Bubble nucleation, although not of major atmospheric relevance, is included for completeness. This book presents a single, go-to resource that will help readers understand the breadth and depth of nucleation, both in theory and in real-world examples. - Offers a single, comprehensive work on water nucleation, including cutting- edge research on ice, cloud and bubble nucleation - Written primarily for atmospheric scientists, but it also presents the theories in such a way that researchers in other disciplines will find it useful - Written by one of the world's foremost experts on ice nucleation
Book Synopsis Nucleation and Atmospheric Aerosols by : Colin D. O'Dowd
Download or read book Nucleation and Atmospheric Aerosols written by Colin D. O'Dowd and published by Springer Science & Business Media. This book was released on 2007-10 with total page 1275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric particles are ubiquitous in the atmosphere: they form the seeds for cloud droplets and they form haze layers, blocking out incoming radiation and contributing to a partial cooling of our climate. They also contribute to poor air quality and health impacts. A large fraction of aerosols are formed from nucleation processes – that is a phase transition from vapour to liquid or solid particles. Examples are the formation of stable clusters about 1 nm in size from molecular collisions and these in turn can grow into larger (100 nm or more) haze particles via condensation to the formation of ice crystals in mixed phase or cold clouds. This book brings together the leading experts from the nucleation and atmospheric aerosols research communities to present the current state-of-the-art knowledge in these related fields. Topics covered are: Nucleation Experiment & Theory, Binary, Homogeneous and Heterogeneous Nucleation, Ion & Cluster Properties During Nucleation, Aerosol Characterisation & Properties, Aerosol Formation, Dynamics and Growth, Marine Aerosol Production, Aerosol-Cloud Interactions, Chemical Composition & Cloud Drop Activation, Remote Sensing of aerosol & clouds and Air Quality-Climate Interactions
Book Synopsis Heterogeneous Ice Nucleation in Droplets Containing Mineral Dust Particles by : Dennis Niedermeier
Download or read book Heterogeneous Ice Nucleation in Droplets Containing Mineral Dust Particles written by Dennis Niedermeier and published by . This book was released on 2012 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oceanic Whitecaps written by E.C. Monahan and published by Springer Science & Business Media. This book was released on 1986-04-30 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: While various volumes havepreviously been de bable, answer to this question lies in the obser vation that while whitecaps are some of the voted to such topics as droplets and bubbles, it is our conceit that this is the first volume dedi most apparent features associated with high sea cated to the description of the phenomenon states, they have also pro\'ed to be someofthe of oceanic whitecapping, and to a considera most difficult objects to measure and describe tion of the role these whitecapsplay in satellite quantitatively, and while scientists as a group marine remote sensing, in sea-salt aerosol gene may like to tackle difficult problems, we ration, and in a broad range ofother sea surface should not be accused ofundue modesty when processes. This observation, reOecting in part we observe that as a group we also have a finite the relatively modest attention paid until re tolerance for frustration and ahuman,perhaps cently by the scientific community to white aesthetic, prejudice in favour ofnatural pheno caps, is noteworthy when one considers that mena that are amcnable to detailed description. collectively whitecaps are to thegeneral public It is appropriate to note that Professor Wood one of the most striking features of the sea cock, to whom this volume is dedicated, ap scape.
Book Synopsis Cloud Dynamics by : Robert A. Houze Jr.
Download or read book Cloud Dynamics written by Robert A. Houze Jr. and published by Academic Press. This book was released on 2014-07-08 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: As models of the Earth/atmosphere system and observations become ever more sophisticated, and concerns about climate change and societal impacts of extreme weather and its forecasting grow, understanding the role of clouds in the atmosphere is increasingly vital. Cloud Dynamics, Second Edition provides the essential information needed to understand how clouds affect climate and weather. This comprehensive book examines the underlying physics and dynamics of every specific type of cloud that occurs in the Earth's atmosphere, showing how clouds differ dynamically depending on whether they occur over oceans or mountains, or as parts of atmospheric storms, such as thunderstorms, tropical cyclones, or warm and cold fronts. Covering both the microphysical and macrophysical aspects of clouds, the book treats all of the physical scales involved in cloud processes, from the microscale of the individual drops and ice particles up to scales of storms in which the clouds occur. As observational technology advances with increasingly sophisticated remote sensing capabilities, detailed understanding of how the dynamics and physics of clouds affect the quantities being measured is of paramount importance. This book underpins the work necessary for proper interpretation of these observations, now and in the future. - Provides the holistic understanding of clouds needed to pursue research on topics vital to life on Earth - Provides in-depth understanding of all types of clouds over all regions of Earth, from the poles to the equator - Includes detailed physical and dynamical insight into the entire spectrum of clouds populating Earth's atmosphere
Book Synopsis Investigation of the Heterogeneous Ice Nucleation Potential of Sea Spray Aerosol by : Lilian A. Dove
Download or read book Investigation of the Heterogeneous Ice Nucleation Potential of Sea Spray Aerosol written by Lilian A. Dove and published by . This book was released on 2018 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bubble bursting at the ocean surface generates smaller film-burst particles and larger jet drop particles that differ in composition. The chemical composition of sea spray aerosols is an important parameter for the evaluation of their impact on the global climate system. This study investigates the role of particle chemistry on the heterogeneous ice nucleation potential of laboratory-generated sea spray aerosols. Cultures of Procholorococcus, a highly abundant marine phytoplankton species, were used as a model source of organic sea spray aerosols. Results show that smaller particles generated from the lysed Procholorococcus cultures were organically enriched and effectively activated as ice nucleating particles at warmer temperatures and lower supersaturations than larger particles. The role of chemical composition in the activation of the particles was studied by measuring the nucleation abilities of single component organic molecules that mimic proteins, lipids, and carbohydrates in Procholorococcus. Amylopectin, agarose, and aspartic acid exhibited nucleation behaviors similar to particles generated from Procholorococcus cultures. Therefore, carbohydrates and proteins with numerous and well-ordered hydrophilic functional groups may determine the ice nucleation potential of organic sea spray aerosols.
Book Synopsis Light Scattering by Ice Crystals by : Kuo-Nan Liou
Download or read book Light Scattering by Ice Crystals written by Kuo-Nan Liou and published by Cambridge University Press. This book was released on 2016-10-06 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume outlines the fundamentals and applications of light scattering, absorption and polarization processes involving ice crystals.
Author :Panel on Aerosol Radiative Forcing and Climate Change Publisher :National Academies Press ISBN 13 :0309588871 Total Pages :180 pages Book Rating :4.3/5 (95 download)
Book Synopsis A Plan for a Research Program on Aerosol Radiative Forcing and Climate Change by : Panel on Aerosol Radiative Forcing and Climate Change
Download or read book A Plan for a Research Program on Aerosol Radiative Forcing and Climate Change written by Panel on Aerosol Radiative Forcing and Climate Change and published by National Academies Press. This book was released on 1996-05-01 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.
Book Synopsis Laboratory Studies of Ice Formation Via Deposition Mode Nucleation Onto Mineral Dust and N-hexane Soot Samples by : Zaminhussein Abdulali Kanji
Download or read book Laboratory Studies of Ice Formation Via Deposition Mode Nucleation Onto Mineral Dust and N-hexane Soot Samples written by Zaminhussein Abdulali Kanji and published by . This book was released on 2006 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory studies are described whereby the heterogeneous ice nucleating ability of various dust samples was studied for particles mounted on a hydrophobic cold stage. Ice formation is observed using digital photography. The relative humidity with respect to ice (RHIce) and temperature conditions of the flow system are validated by observing (NH4)2SO 4 deliquescence. Four types of solid mineral samples, including authentic Saharan dust, and commercial samples of alumina, silica and montmorillonite, were investigated in the deposition freezing mode. The size of the dust particles ranged from 0.5 to 5 microns, and the temperature range was from 263 to 218 K. With roughly 104 particles present on the cold stage, the onset for ice formation was observed at low relative humidities, between 102 and 108% RHIce, for all samples and temperatures. This indicates that deposition mode nucleation is an efficient mode of ice formation, particularly under the cold temperatures prevalent in the cirrus regime. By contrast, ice deposition onto n-hexane soot particles was not nearly so efficient. Nucleation rates prevalent in the experiment are calculated as a function of relative humidity from a suite of experiments conducted with Saharan dust where the dependence of the onset RHIce as a function of the total dust surface area was measured.
Book Synopsis Ice Nucleation of Metal Oxides as Model Systems of Atmospheric Aerosol Particles by : Esther Chong
Download or read book Ice Nucleation of Metal Oxides as Model Systems of Atmospheric Aerosol Particles written by Esther Chong and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanism of ice nucleation continues to be an ongoing discussion within the scientific community. The debate centers around two central questions: how an aerosol particle interacts with water and what characteristics of the particle promote ice nucleation. Understanding of aerosol-cloud interactions, whether it is the formation of cloud condensation nuclei or ice nuclei, has been a source of some of the highest uncertainty in determining the radiative budget of the Earth. The complexity of atmospheric aerosol particles makes it difficult to decide on which particular characteristics on a particle affects its ice nucleation activity. To study specific features, we used model metal oxide systems to control as many variables as possible. By systematically determining which properties and to what extent they affect ice nucleation, we may extrapolate the mechanism of ice nucleation and decrease the uncertainty around aerosol-cloud interactions. The metal oxide systems included aluminum, iron, titanium, and manganese oxide, which are all found as components in mineral dust. As one of the most prevalent ice nucleating particles in the atmosphere, mineral dust is an ideal atmospheric particle for us to simulate with our model systems. A combination of X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used to characterize our model systems. The aluminum oxides were chosen to study the effect of crystallinity and lattice matching on ice nucleation. The three most crystalline samples, corundum [[alpha]-Al2O3], gibbsite [Al(OH)3], and bayerite [Al(OH)3], were also found to have the highest ice nucleation activity. Then, calculations of the lattice match of the aluminum oxides with respect to hexagonal ice found that the best ice nucleating particle was corundum [[alpha]-Al2O3], which had the highest lattice match along the a- and b-axis. Therefore, a combination of high crystallinity and high lattice match with hexagonal ice correlated with a high ice nucleation activity. Then, iron oxides were studied to expand further on the aluminum oxide system by exploring if the lattice match is a viable property to determine ice nucleation activity despite the difference in composition. Overall, wüstite [FeO] had a high lattice match and the highest ice nucleation activity among the iron oxide samples. Because wüstite [FeO] was milled for the ice nucleation experiments, the effect of milling on ice nucleation was also studied. By comparing milled and 20 [mu]m sieved of both wüstite [FeO] and MnO, we saw that physical defects formed by the mill had minimal improvements on the ice nucleation activity of MnO. XPS showed that milled wüstite [FeO] had more exposed hydroxyls at the surface compared to the sieved wüstite [FeO]. In contrast, milled and sieved MnO showed similar concentrations of oxygen and hydroxyl species. Thus, the high lattice match and the exposure of hydroxyl groups after milling were the leading factors to wüstite [FeO]'s high ice nucleation activity. The last two systems, titanium and manganese oxide, were chosen to confirm that the lattice match trend could be applied to a variety of particles. For the titanium oxides, Ti2O3 was the best ice nucleating particle, but the lattice match was not high. We hypothesize that the dissociation and adsorption of water at the surface of titanium oxides could affect their ice nucleation. The manganese oxides followed the lattice match trend. MnO had the highest ice nucleation activity and the highest lattice match. Thus, the data compilation of all four metal oxides found that a high lattice match with hexagonal ice has a reasonably strong correlation with the immersion ice nucleation activity. The commonality of the lattice match trend between these metal oxide systems has implications of more properties that are good indicators for the ice nucleation activity over a wide range of compounds. If enough of these properties are identified, then it would be possible for cloud models better to predict the ice nucleation activity of complex atmospheric particles and decrease the uncertainty of aerosol-cloud interactions.
