scholarly journals Glassy aerosols with a range of compositions nucleate ice heterogeneously at cirrus temperatures

2012 ◽  
Vol 12 (18) ◽  
pp. 8611-8632 ◽  
Author(s):  
T. W. Wilson ◽  
B. J. Murray ◽  
R. Wagner ◽  
O. Möhler ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Citric Acid ◽  
Glassy State ◽  
Dicarboxylic Acids ◽  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Chemical Compositions ◽  
Tropical Tropopause ◽  
Cloud Models

Abstract. Atmospheric secondary organic aerosol (SOA) is likely to exist in a semi-solid or glassy state, particularly at low temperatures and humidities. Previously, it has been shown that glassy aqueous citric acid aerosol is able to nucleate ice heterogeneously under conditions relevant to cirrus in the tropical tropopause layer (TTL). In this study we test if glassy aerosol distributions with a range of chemical compositions heterogeneously nucleate ice under cirrus conditions. Three single component aqueous solution aerosols (raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA) and levoglucosan) and one multi component aqueous solution aerosol (raffinose mixed with five dicarboxylic acids and ammonium sulphate) were studied in both the liquid and glassy states at a large cloud simulation chamber. The investigated organic compounds have similar functionality to oxidised organic material found in atmospheric aerosol and have estimated temperature/humidity induced glass transition thresholds that fall within the range predicted for atmospheric SOA. A small fraction of aerosol particles of all compositions were found to nucleate ice heterogeneously in the deposition mode at temperatures relevant to the TTL (<200 K). Raffinose and HMMA, which form glasses at higher temperatures, nucleated ice heterogeneously at temperatures as high as 214.6 and 218.5 K respectively. We present the calculated ice active surface site density, ns, of the aerosols tested here and also of glassy citric acid aerosol as a function of relative humidity with respect to ice (RHi). We also propose a parameterisation which can be used to estimate heterogeneous ice nucleation by glassy aerosol for use in cirrus cloud models up to ~220 K. Finally, we show that heterogeneous nucleation by glassy aerosol may compete with ice nucleation on mineral dust particles in mid-latitudes cirrus.

scholarly journals Glassy aerosols with a range of compositions nucleate ice heterogeneously at cirrus temperatures

2012 ◽  
Vol 12 (4) ◽  
pp. 8979-9033 ◽  
Author(s):  
T. W. Wilson ◽  
B. J. Murray ◽  
R. Wagner ◽  
O. Möhler ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Citric Acid ◽  
Glassy State ◽  
Dicarboxylic Acids ◽  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Chemical Compositions ◽  
Tropical Tropopause ◽  
Cloud Models

Abstract. Atmospheric secondary organic aerosol (SOA) is likely to exist in an ultra viscous or glassy state, particularly at low temperatures and humidities. It has also been shown that glassy aqueous citric acid aerosol is able to nucleate ice heterogeneously under conditions relevant to cirrus in the tropical tropopause layer (TTL). In this study we test if glassy aerosols with a range of chemical compositions heterogeneously nucleate ice under cirrus conditions. Three single component aqueous solution aerosols (raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA) and levoglucosan) and one multi component aqueous solution aerosol (raffinose mixed with five dicarboxylic acids and ammonium sulphate) were studied in both the liquid and glassy states at a large cloud simulation chamber. The investigated organic compounds have similar functionality to oxidised organic material found in atmospheric aerosol and have estimated temperature/humidity induced glass transition thresholds that fall within the range predicted for atmospheric SOA. All the aerosols tested were found to nucleate ice heterogeneously in the deposition mode at temperatures relevant to the TTL (<200 K). Raffinose and HMMA, which form glasses at higher temperatures, nucleated ice heterogeneously at temperatures as high as 214.6 and 218.5 K respectively. We present the calculated ice active surface site density, ns, of the aerosols tested here and also of glassy citric acid aerosol as a function of relative humidity with respect to ice (RHi). We also propose a parameterisation which can be used to estimate heterogeneous ice nucleation by glassy aerosol for use in cirrus cloud models up to ~220 K. Finally, we show that heterogeneous nucleation by glassy aerosol may compete with ice nucleation on mineral dust particles in mid-latitudes cirrus.

scholarly journals A comprehensive parameterization of heterogeneous ice nucleation of dust surrogate: laboratory study with hematite particles and its application to atmospheric models

2014 ◽  
Vol 14 (23) ◽  
pp. 13145-13158 ◽  
Author(s):  
N. Hiranuma ◽  
M. Paukert ◽  
I. Steinke ◽  
K. Zhang ◽  
G. Kulkarni ◽  
...  
Keyword(s):  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Atmospheric Dust ◽  
Experimental Conditions ◽  
Cloud Properties ◽  
Cloud Models ◽  
Order Of Magnitude ◽  
Lower Temperature ◽  
Heterogeneous Ice Nucleation

Abstract. A new heterogeneous ice nucleation parameterization that covers a wide temperature range (−36 to −78 °C) is presented. Developing and testing such an ice nucleation parameterization, which is constrained through identical experimental conditions, is important to accurately simulate the ice nucleation processes in cirrus clouds. The ice nucleation active surface-site density (ns) of hematite particles, used as a proxy for atmospheric dust particles, were derived from AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber measurements under water subsaturated conditions. These conditions were achieved by continuously changing the temperature (T) and relative humidity with respect to ice (RHice) in the chamber. Our measurements showed several different pathways to nucleate ice depending on T and RHice conditions. For instance, almost T-independent freezing was observed at −60 °C < T < −50 °C, where RHice explicitly controlled ice nucleation efficiency, while both T and RHice played roles in other two T regimes: −78 °C < T < −60 °C and −50 °C < T < −36 °C. More specifically, observations at T lower than −60 °C revealed that higher RHice was necessary to maintain a constant ns, whereas T may have played a significant role in ice nucleation at T higher than −50 °C. We implemented the new hematite-derived ns parameterization, which agrees well with previous AIDA measurements of desert dust, into two conceptual cloud models to investigate their sensitivity to the new parameterization in comparison to existing ice nucleation schemes for simulating cirrus cloud properties. Our results show that the new AIDA-based parameterization leads to an order of magnitude higher ice crystal concentrations and to an inhibition of homogeneous nucleation in lower-temperature regions. Our cloud simulation results suggest that atmospheric dust particles that form ice nuclei at lower temperatures, below −36 °C, can potentially have a stronger influence on cloud properties, such as cloud longevity and initiation, compared to previous parameterizations.

scholarly journals Irreversible loss of ice nucleation active sites in mineral dust particles caused by sulphuric acid condensation

2010 ◽  
Vol 10 (23) ◽  
pp. 11471-11487 ◽  
Author(s):  
R. C. Sullivan ◽  
M. D. Petters ◽  
P. J. DeMott ◽  
S. M. Kreidenweis ◽  
H. Wex ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Active Sites ◽  
Mineral Dust ◽  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Ammonia Gas ◽  
Surface Sites ◽  
Active Surface Sites ◽  
Acid Coating

Abstract. During the FROST-2 (FReezing Of duST) measurement campaign conducted at the Leipzig Aerosol Cloud Interaction Simulator (LACIS), we investigated changes in the ice nucleation properties of 300 nm Arizona Test Dust mineral particles following thermochemical processing by varying amounts and combinations of exposure to sulphuric acid vapour, ammonia gas, water vapour, and heat. The processed particles' heterogeneous ice nucleation properties were determined in both the water subsaturated and supersaturated humidity regimes at −30 °C and −25 °C using Colorado State University's continuous flow diffusion chamber. The amount of sulphuric acid coating material was estimated by an aerosol mass spectrometer and from CCN-derived hygroscopicity measurements. The condensation of sulphuric acid decreased the dust particles' ice nucleation ability in proportion to the amount of sulphuric acid added. Heating the coated particles in a thermodenuder at 250 °C – intended to evaporate the sulphuric acid coating – reduced their freezing ability even further. We attribute this behaviour to accelerated acid digestion of ice active surface sites by heat. Exposing sulphuric acid coated dust to ammonia gas produced particles with similarly poor freezing potential; however a portion of their ice nucleation ability could be restored after heating in the thermodenuder. In no case did any combination of thermochemical treatments increase the ice nucleation ability of the coated mineral dust particles compared to unprocessed dust. These first measurements of the effect of identical chemical processing of dust particles on their ice nucleation ability under both water subsaturated and mixed-phase supersaturated cloud conditions revealed that ice nucleation was more sensitive to all coating treatments in the water subsaturated regime. The results clearly indicate irreversible impairment of ice nucleation activity in both regimes after condensation of concentrated sulphuric acid. This implies that the sulphuric acid coating caused permanent chemical and/or physical modification of the ice active surface sites; the possible dissolution of the coating during droplet activation did not restore all immersion/condensation-freezing ability.

scholarly journals The WeIzmann Supercooled Droplets Observation on a Microarray (WISDOM) and application for ambient dust

2018 ◽  
Vol 11 (1) ◽  
pp. 233-248 ◽  
Author(s):  
Naama Reicher ◽  
Lior Segev ◽  
Yinon Rudich
Keyword(s):  
Active Surface ◽  
Ice Nucleation ◽  
Saharan Dust ◽  
Dust Particles ◽  
Active Surface Site ◽  
Immersion Freezing ◽  
Measurement Uncertainties ◽  
Homogeneous Freezing ◽  
Validation Experiments

Abstract. The WeIzmann Supercooled Droplets Observation on Microarray (WISDOM) is a new setup for studying ice nucleation in an array of monodisperse droplets for atmospheric implications. WISDOM combines microfluidics techniques for droplets production and a cryo-optic stage for observation and characterization of freezing events of individual droplets. This setup is designed to explore heterogeneous ice nucleation in the immersion freezing mode, down to the homogeneous freezing of water (235 K) in various cooling rates (typically 0.1–10 K min−1). It can also be used for studying homogeneous freezing of aqueous solutions in colder temperatures. Frozen fraction, ice nucleation active surface site densities and freezing kinetics can be obtained from WISDOM measurements for hundreds of individual droplets in a single freezing experiment. Calibration experiments using eutectic solutions and previously studied materials are described. WISDOM also allows repeatable cycles of cooling and heating for the same array of droplets. This paper describes the WISDOM setup, its temperature calibration, validation experiments and measurement uncertainties. Finally, application of WISDOM to study the ice nucleating particle (INP) properties of size-selected ambient Saharan dust particles is presented.

scholarly journals Laboratory studies of immersion and deposition mode ice nucleation of ozone aged mineral dust particles

2013 ◽  
Vol 13 (17) ◽  
pp. 9097-9118 ◽  
Author(s):  
Z. A. Kanji ◽  
A. Welti ◽  
C. Chou ◽  
O. Stetzer ◽  
U. Lohmann
Keyword(s):  
Mineral Dust ◽  
Active Surface ◽  
Freezing Temperature ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Laboratory Studies ◽  
Ambient Conditions ◽  
First Results ◽  
Deposition Mode ◽  
Heterogeneous Ice Nucleation

Abstract. Ice nucleation in the atmosphere is central to the understanding the microphysical properties of mixed-phase and cirrus clouds. Ambient conditions such as temperature (T) and relative humidity (RH), as well as aerosol properties such as chemical composition and mixing state play an important role in predicting ice formation in the troposphere. Previous field studies have reported the absence of sulfate and organic compounds on mineral dust ice crystal residuals sampled at mountain top stations or aircraft based measurements despite the long-range transport mineral dust is subjected to. We present laboratory studies of ice nucleation for immersion and deposition mode on ozone aged mineral dust particles for 233 < T < 263 K. Heterogeneous ice nucleation of untreated kaolinite (Ka) and Arizona Test Dust (ATD) particles is compared to corresponding aged particles that are subjected to ozone concentrations of 0.4–4.3 ppmv in a stainless steel aerosol tank. The portable ice nucleation counter (PINC) and immersion chamber combined with the Zurich ice nucleation chamber (IMCA-ZINC) are used to conduct deposition and immersion mode measurements, respectively. Ice active fractions as well as ice active surface site densities (ns) are reported and observed to increase as a function of decreasing temperature. We present first results that demonstrate enhancement of the ice nucleation ability of aged mineral dust particles in both the deposition and immersion mode due to ageing. We also present the first results to show a suppression of heterogeneous ice nucleation activity without the condensation of a coating of (in)organic material. In immersion mode, low ozone exposed Ka particles showed enhanced ice activity requiring a median freezing temperature of 1.5 K warmer than that of untreated Ka, whereas high ozone exposed ATD particles showed suppressed ice nucleation requiring a median freezing temperature of 3 K colder than that of untreated ATD. In deposition mode, low exposure Ka had ice active fractions of an order of magnitude higher than untreated Ka, whereas high ozone exposed ATD had ice active fractions up to a factor of 4 lower than untreated ATD. From our results, we derive and present parameterizations in terms of ns(T) that can be used in models to predict ice nuclei concentrations based on available aerosol surface area.

scholarly journals Studies of heterogeneous freezing by three different desert dust samples

2009 ◽  
Vol 9 (8) ◽  
pp. 2805-2824 ◽  
Author(s):  
P. J. Connolly ◽  
O. Möhler ◽  
P. R. Field ◽  
H. Saathoff ◽  
R. Burgess ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Active Surface ◽  
Ice Nucleation ◽  
Surface Site ◽  
Smooth Curves ◽  
Site Density ◽  
Cloud Models ◽  
Active Surface Site ◽  
Three Samples ◽  
Good Agreement

Abstract. We present results of experiments at the aerosol interactions and dynamics in the atmosphere (AIDA) chamber facility looking at the freezing of water by three different types of mineral particles at temperatures between −12°C and −33°C. The three different dusts are Asia Dust-1 (AD1), Sahara Dust-2 (SD2) and Arizona test Dust (ATD). The dust samples used had particle concentrations of sizes that were log-normally distributed with mode diameters between 0.3 and 0.5 μm and standard deviations, σg, of 1.6–1.9. The results from the freezing experiments are consistent with the singular hypothesis of ice nucleation. The dusts showed different nucleation abilities, with ATD showing a rather sharp increase in ice-active surface site density at temperatures less than −24°C. AD1 was the next most efficient freezing nuclei and showed a more gradual increase in activity than the ATD sample. SD2 was the least active freezing nuclei. We used data taken with particle counting probes to derive the ice-active surface site density forming on the dust as a function of temperature for each of the three samples and polynomial curves are fitted to this data. The curve fits are then used independently within a bin microphysical model to simulate the ice formation rates from the experiments in order to test the validity of parameterising the data with smooth curves. Good agreement is found between the measurements and the model for AD1 and SD2; however, the curve for ATD does not yield results that agree well with the observations. The reason for this is that more experiments between −20 and −24°C are needed to quantify the rather sharp increase in ice-active surface site density on ATD in this temperature regime. The curves presented can be used as parameterisations in atmospheric cloud models where cooling rates of approximately 1°C min−1 or more are present to predict the concentration of ice crystals forming by the condensation-freezing mode of ice nucleation. Finally a polynomial is fitted to all three samples together in order to have a parameterisation describing the average ice-active surface site density vs. temperature for an equal mixture of the three dust samples.

scholarly journals The WeIzmann Supercooled Droplets Observation (WISDOM) on a Microarray and application for ambient dust

2017 ◽  
Author(s):  
Naama Reicher ◽  
Lior Segev ◽  
Yinon Rudich
Keyword(s):  
Active Surface ◽  
Mineral Oil ◽  
Ice Nucleation ◽  
Saharan Dust ◽  
Dust Particles ◽  
Active Surface Site ◽  
Immersion Freezing ◽  
Measurement Uncertainties ◽  
Validation Experiments

Abstract. The WeIzmann Supercooled Droplets Observation on Microarray (WISDOM) is a new setup for studying ice nucleation in an array of monodisperse droplets for atmospheric implications. WISDOM combines microfluidics techniques for droplets production and a cryo-optic stage for observation and characterization of freezing events of individual droplets. This setup is designed to explore heterogeneous ice nucleation in the immersion freezing mode, down to the homogenous freezing of water (235 K) in various cooling rates (typically 0.1-10 K min−1). It can also be used for studying homogenous freezing of aqueous solutions in colder temperatures. Frozen fraction, ice nucleation active surface site (INAS) densities and freezing kinetics can be obtained from WISDOM measurements with excellent statistics of hundreds of individual droplets in a single freezing experiment. Droplets are surrounded by a mineral oil phase which assures the isolation of the droplets and prevents mutual seeding, mass transfer or evaporation, and hence increases the reliability and reproducibility of the measurement. WISDOM also allows repeatable cycles of cooling and heating for the same array of droplets. This paper describes the WISDOM setup, its temperature calibration, validation experiments and measurement uncertainties. Finally, application of WISDOM to study the INP properties of size-selected ambient Saharan dust particles is presented.

scholarly journals Irreversible loss of ice nucleation active sites in mineral dust particles caused by sulphuric acid condensation

2010 ◽  
Vol 10 (7) ◽  
pp. 16901-16940 ◽  
Author(s):  
R. C. Sullivan ◽  
M. D. Petters ◽  
P. J. DeMott ◽  
S. M. Kreidenweis ◽  
H. Wex ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Active Sites ◽  
Mineral Dust ◽  
Active Surface ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Ammonia Gas ◽  
Surface Sites ◽  
Active Surface Sites ◽  
Acid Coating

Abstract. During the FROST-2 (FReezing Of duST) measurement campaign conducted at the Leipzig Aerosol Cloud Interaction Simulator (LACIS), we investigated changes in the ice nucleation properties of 300 nm Arizona test dust mineral particles following thermochemical processing by varying amounts and combinations of exposure to sulphuric acid vapour, ammonia gas, water vapour, and heat. The processed aerosol's heterogeneous ice nucleation properties were determined in both the water subsaturated and supersaturated humidity regimes at −30 °C and −25 °C using Colorado State University's continuous flow diffusion chamber. The amount of sulphuric acid coating material was estimated by an aerosol mass spectrometer and from CCN-derived hygroscopicity measurements. The condensation of sulphuric acid decreased the dust particles' ice nucleation ability in proportion to the amount of sulphuric acid added. Heating the coated particles in a thermodenuder at 250 °C – intended to evaporate the sulphuric acid coating – reduced their freezing ability even further. We attribute this behaviour to accelerated acid digestion of ice active surface sites by heat. Exposing sulphuric acid coated dust to ammonia gas produced particles with similarly poor freezing potential; however a portion of their ice nucleation ability could be restored after heating in the thermodenuder. In no case did any combination of thermochemical treatments increase the ice nucleation ability of the coated mineral dust particles compared to unprocessed dust. These first measurements of the effect of identical chemical processing of dust particles on their ice nucleation ability in both water subsaturated and mixed-phase supersaturated cloud conditions revealed that ice nucleation was more sensitive to all coating treatments in the water subsaturated regime. The results clearly indicate irreversible impairment of ice nucleation activity in both regimes after condensation of concentrated sulphuric acid. This implies that the sulphuric acid coating caused permanent chemical and/or physical modification of the ice active surface sites; the possible dissolution of the coating during droplet activation did not restore all immersion/condensation-freezing ability.

scholarly journals A comprehensive parameterization of heterogeneous ice nucleation of dust surrogate: laboratory study with hematite particles and its application to atmospheric models

2014 ◽  
Vol 14 (11) ◽  
pp. 16493-16528 ◽  
Author(s):  
N. Hiranuma ◽  
M. Paukert ◽  
I. Steinke ◽  
K. Zhang ◽  
G. Kulkarni ◽  
...  
Keyword(s):  
Ice Nucleation ◽  
Dust Particles ◽  
Ice Crystal ◽  
Atmospheric Models ◽  
Experimental Conditions ◽  
Cloud Properties ◽  
Ice Nuclei ◽  
Cloud Models ◽  
Order Of Magnitude ◽  
Heterogeneous Ice Nucleation

Abstract. A new heterogeneous ice nucleation parameterization that covers a wide temperature range (−36 to −78 °C) is presented. Developing and testing such an ice nucleation parameterization, which is constrained through identical experimental conditions, is critical in order to accurately simulate the ice nucleation processes in cirrus clouds. The surface-scaled ice nucleation efficiencies of hematite particles, inferred by ns, were derived from AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber measurements under water subsaturated conditions that were realized by continuously changing temperature (T) and relative humidity with respect to ice (RHice) in the chamber. Our measurements showed several different pathways to nucleate ice depending on T and RHice conditions. For instance, almost T-independent freezing was observed at −60 °C < T < −50 °C, where RHice explicitly controlled ice nucleation efficiency, while both T and RHice played roles in other two T regimes: −78 °C < T < −60 °C and −50 °C < T < −36 °C. More specifically, observations at T colder than −60 °C revealed that higher RHice was necessary to maintain constant ns, whereas T may have played a significant role in ice nucleation at T warmer than −50 °C. We implemented new ns parameterizations into two cloud models to investigate its sensitivity and compare with the existing ice nucleation schemes towards simulating cirrus cloud properties. Our results show that the new AIDA-based parameterizations lead to an order of magnitude higher ice crystal concentrations and inhibition of homogeneous nucleation in colder temperature regions. Our cloud simulation results suggest that atmospheric dust particles that form ice nuclei at lower temperatures, below −36 °C, can potentially have stronger influence on cloud properties such as cloud longevity and initiation when compared to previous parameterizations.

scholarly journals Studies of heterogeneous freezing by three different desert dust samples

2009 ◽  
Vol 9 (1) ◽  
pp. 463-514 ◽  
Author(s):  
P. J. Connolly ◽  
O. Möhler ◽  
P. R. Field ◽  
H. Saathoff ◽  
R. Burgess ◽  
...  
Keyword(s):  
Sharp Increase ◽  
Active Surface ◽  
Ice Nucleation ◽  
Surface Site ◽  
Smooth Curves ◽  
Site Density ◽  
Cloud Models ◽  
Active Surface Site ◽  
Three Samples ◽  
Good Agreement

Abstract. We present results of experiments at the aerosol interactions and dynamics in the atmosphere (AIDA) chamber facility looking at the freezing of water by three different types of mineral particles at temperatures between −12°C and −33°C. The three different dusts are Asia Dust-1 (AD1), Sahara Dust-2 (SD2) and Arizona test Dust (ATD). The dust samples used had particle concentrations of sizes that were log-normally distributed with mode diameters between 0.3 and 0.5 μm and standard deviations, σg, of 1.6–1.9. The results from the freezing experiments are consistent with the singular hypothesis of ice nucleation. The dusts showed different nucleation abilities, with ATD showing a rather sharp increase in ice-active surface site density at temperatures less than −24°C. AD1 was the next most efficient freezing nuclei and showed a more gradual increase in activity than the ATD sample. SD2 was the least active freezing nuclei. We used data taken with particle counting probes to derive the ice-active surface site density forming on the dust as a function of temperature for each of the three samples and polynomial curves are fitted to this data. The curve fits are then used independently within a bin microphysical model to simulate the ice formation rates from the experiments in order to test the validity of parameterising the data with smooth curves. Good agreement is found between the measurements and the model for AD1 and SD2; however, the curve for ATD does not yield results that agree well with the observations. The reason for this is that more experiments between −20 and −24°C are needed to quantify the rather sharp increase in ice-active surface site density on ATD in this temperature regime. The curves presented can be used as parameterisations in atmospheric cloud models where cooling rates of approximately 1°C min−1 or more are present to predict the concentration of ice crystals forming by the condensation-freezing mode of ice nucleation. Finally a polynomial is fitted to all three samples together in order to have a parameterisation describing the average ice-active surface site density vs. temperature for an equal mixture of the three dust samples.

Sign in / Sign up

Export Citation Format

Share Document