In-situ observations of aerosol particles remaining from evaporated cirrus crystals: Comparing clean and polluted air masses

Seifert, M.; Ström, Johan; Krejčí, Radovan; Minikin, Andreas; Petzold, A.; Gayet, Jean-François; Schumann, U.; Ovarlez, J.

doi:10.5194/acp-3-1037-2003

Cited by 51 publications

(29 citation statements)

References 30 publications

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“…Heterogeneous nucleation of ice is regarded as a possible formation mechanism of cirrus ice clouds [ Heymsfield et al , 1998; DeMott et al , 1998; Seifert et al , 2003; Ström et al , 2003; Haag et al , 2003]. It has been shown that mineral dust particles have a significant impact on cloud formation, cloud properties, and precipitation [ Levin et al , 1996; Rosenfeld et al , 2001; Yin et al , 2002; DeMott et al , 2003; Sassen et al , 2003; Toon , 2003; Mahowald and Kiehl , 2003; Sassen , 2005].…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous nucleation of ice on surrogates of mineral dust

2006

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[1] Field studies have shown that mineral dust particles can act as ice nuclei in cirrus clouds. Here, we present a laboratory investigation of heterogeneous ice nucleation on surrogates of mineral dust particles, in particular pure Arizona test dust (ATD) particles, and ATD particles coated with sulfuric acid. The experiments have been performed using a new apparatus in which ice formation on the particles is determined by optical microscopy at temperatures between 197 and 260 K and relative humidities up to water saturation. The experiments reveal that pure and sulfuric acid coated ATD particles nucleate ice at considerably lower relative humidities than required for homogeneous ice nucleation in liquid aerosols. Nucleation occurred over a broad relative humidity range indicating that the different minerals contained in ATD have different ice nucleation thresholds. No significant difference in the ice nucleation ability of pure and H 2 SO 4 coated ATD particles was observed. Below 240 K, ice nucleated on ATD particles apparently by deposition nucleation. Preactivation of ATD particles, that is, a reduction in supersaturation, required for heterogeneous ice nucleation after a previous ice nucleation event on the same particle, has been observed for temperatures as low as 200 K. Differences of 10-30% in the onset RH ice values were obtained for particles with or without preactivation. The results indicate that pure and sulfuric acid coated mineral dust particles may act as efficient ice nuclei in the atmosphere. Preactivation of the particles should be considered when modeling long-range transport of mineral dust particles and their impact on cloud formation.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous nucleation of ice on surrogates of mineral dust

2006

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“…While it is impossible to directly observe ice nucleation in situ (Hegg and Baker, 2009), heterogeneous ice nucleation is regarded as a possible formation mechanism for cirrus DeMott et al, 1998;Seifert et al, 2003;Haag et al, 2003) and mixed-phase clouds (Rogers et al, 2001b;DeMott et al, 2003;Verlinde et al, 2007).…”

Section: P a Alpert Et Al: Homogeneous And Heterogeneous Ice Nuclementioning

confidence: 99%

Ice nucleation from aqueous NaCl droplets with and without marine diatoms

2011

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Abstract. Ice formation in the atmosphere by homogeneous and heterogeneous nucleation is one of the least understood processes in cloud microphysics and climate. Here we describe our investigation of the marine environment as a potential source of atmospheric IN by experimentally observing homogeneous ice nucleation from aqueous NaCl droplets and comparing against heterogeneous ice nucleation from aqueous NaCl droplets containing intact and fragmented diatoms. Homogeneous and heterogeneous ice nucleation are studied as a function of temperature and water activity, a w . Additional analyses are presented on the dependence of diatom surface area and aqueous volume on heterogeneous freezing temperatures, ice nucleation rates, ω het , ice nucleation rate coefficients, J het , and differential and cumulative ice nuclei spectra, k(T ) and K(T ), respectively. Homogeneous freezing temperatures and corresponding nucleation rate coefficients are in agreement with the water activity based homogeneous ice nucleation theory within experimental and predictive uncertainties. Our results confirm, as predicted by classical nucleation theory, that a stochastic interpretation can be used to describe the homogeneous ice nucleation process. Heterogeneous ice nucleation initiated by intact and fragmented diatoms can be adequately represented by a modified water activity based ice nucleation theory. A horizontal shift in water activity, a w,het = 0.2303, of the ice melting curve can describe median heterogeneous freezing temperatures. Individual freezing temperatures showed no dependence on available diatom surface area and aqueous volume. Determined at median diatom freezing temperatures for a w from 0.8 to −4.1 ×10 4 cm −2 . The experimentally derived ice nucleation rates and nuclei spectra allow us to estimate ice particle production which we subsequently use for a comparison with observed ice crystal concentrations typically found in cirrus and polar marine mixed-phase clouds. Differences in application of time-dependent and time-independent analyses to predict ice particle production are discussed.

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“…In the last decade much attention has been given to laboratory studies on heterogeneous ice nucleation (e.g., Hoose and Möhler, 2012, and references therein) and to field studies (e.g., DeMott et al, 2003a, b;Prenni et al, 2009a, b;Klein et al, 2010a;Santachiara et al, 2010;Ardon-Dryer et al, 2011;Conen et al, 2012), all of which contributed greatly to our understanding of IN distribution in different parts of the world. In addition, analysis of the chemical composition of IN residuals from airborne measurements using electron microscopy and mass spectroscopy (e.g., Seifert et al, 2003;Cziczo et al, 2003Cziczo et al, , 2006Cziczo et al, , 2013Froyd et al, 2010) have added a deeper understanding about the nature of some of the IN in the atmosphere.…”

Section: K Ardon-dryer and Z Levin: Ground-based Measurements Of Immentioning

confidence: 99%

Ground-based measurements of immersion freezing in the eastern Mediterranean

Ardon‐Dryer

Levin

2014

Atmos. Chem. Phys.

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Abstract. Ice nuclei were measured in immersion-freezing mode in the eastern Mediterranean region using the FRIDGE-TAU (FRankfurt Ice-nuclei Deposition freezinG Experiment, the Tel Aviv University version) chamber. Aerosol particles were sampled during dust storms and on clean and polluted days (e.g., Lag BaOmer). The aerosol immersion-freezing potential was analyzed in the laboratory using a drop-freezing method. Droplets from all the samples were found to freeze between −11.8 • C and −28.9 • C. Immersion-freezing nuclei (FN) concentrations range between 0.16 L −1 and 234 L −1 , while the activated fraction (AF) ranges between 8.7 × 10 −8 and 4.9 × 10 −4 . The median temperature at which the drops from each filter froze was found to be correlated with the corresponding daily average of PM 10 , PM 2.5 and PM 10 -PM 2.5 . A higher correlation value between FN concentrations and PM 10 -PM 2.5 suggests that the larger particles are generally more effective as FN.The measurements were divided into dust storms and "clean" conditions (this is a relative term, because dust particles are always present in the atmosphere is this region) based on the air mass back trajectories and the aerosol mass concentrations (PM 10 ). Droplets containing ambient particles from dust storm days froze at higher temperatures than droplets containing particles from clean days. Statistically significant differences were found between dust storms and clean conditions primarily in terms of the initial temperature at which the first drops froze, the median freezing temperature and the aerosol loading (PM values). FN concentrations and AF values in dust storms were larger by more than a factor of 2 than in the clean conditions. This observation agrees with previous studies showing that some dust particles are almost always present in the atmosphere in this region.Measurements of aerosol particles emitted from wood burning bonfires during a Lag BaOmer holiday showed that although a high concentration of particles was emitted, those particles' effectiveness as FN was relatively poor. The most likely reason for the low FN efficiency is the combination of relatively low fire temperatures and high organic carbon fraction in the aerosols.

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In-situ observations of aerosol particles remaining from evaporated cirrus crystals: Comparing clean and polluted air masses

Cited by 51 publications

References 30 publications

Heterogeneous nucleation of ice on surrogates of mineral dust

Heterogeneous nucleation of ice on surrogates of mineral dust

Ice nucleation from aqueous NaCl droplets with and without marine diatoms

Ground-based measurements of immersion freezing in the eastern Mediterranean

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