A new instrument for measuring cloud condensation nuclei: Cloud condensation nucleus “remover”

1998 ◽  
Vol 103 (D21) ◽  
pp. 28013-28019 ◽  
Author(s):  
Qiang Ji ◽  
Glenn E. Shaw ◽  
Will Cantrell
Keyword(s):  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Condensation Nuclei ◽  
New Instrument

scholarly journals Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

2013 ◽  
Vol 13 (16) ◽  
pp. 7983-7996 ◽  
Author(s):  
Z. J. Wu ◽  
L. Poulain ◽  
S. Henning ◽  
K. Dieckmann ◽  
W. Birmili ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Sampling Period ◽  
Cloud Condensation Nucleus ◽  
Mountain Range ◽  
Mixing Rule ◽  
Hygroscopic Growth ◽  
Parameter Values ◽  
Ccn Activity

Abstract. Particle hygroscopic growth at 90% RH (relative humidity), cloud condensation nuclei (CCN) activity, and size-resolved chemical composition were concurrently measured in the Thüringer Wald mid-level mountain range in central Germany in the fall of 2010. The median hygroscopicity parameter values, κ, of 50, 75, 100, 150, 200, and 250 nm particles derived from hygroscopicity measurements are respectively 0.14, 0.14, 0.17, 0.21, 0.24, and 0.28 during the sampling period. The closure between HTDMA (Hygroscopicity Tandem Differential Mobility Analyzers)-measured (κHTDMA) and chemical composition-derived (κchem) hygroscopicity parameters was performed based on the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. Using size-averaged chemical composition, the κ values are substantially overpredicted (30 and 40% for 150 and 100 nm particles). Introducing size-resolved chemical composition substantially improved closure. We found that the evaporation of NH4NO3, which may happen in a HTDMA system, could lead to a discrepancy in predicted and measured particle hygroscopic growth. The hygroscopic parameter of the organic fraction, κorg, is positively correlated with the O : C ratio (κorg = 0.19 × (O : C) − 0.03). Such correlation is helpful to define the κorg value in the closure study. κ derived from CCN measurement was around 30% (varied with particle diameters) higher than that determined from particle hygroscopic growth measurements (here, hydrophilic mode is considered only). This difference might be explained by the surface tension effects, solution non-ideality, gas-particle partitioning of semivolatile compounds, and the partial solubility of constituents or non-dissolved particle matter. Therefore, extrapolating from HTDMA data to properties at the point of activation should be done with great care. Finally, closure study between CCNc (cloud condensation nucleus counter)-measured (κCCN) and chemical composition (κCCN, chem) was performed using CCNc-derived κ values for individual components. The results show that the κCCN can be well predicted using particle size-resolved chemical composition and the ZSR mixing rule.

scholarly journals No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

2012 ◽  
Vol 12 (6) ◽  
pp. 15373-15417 ◽  
Author(s):  
E. M. Dunne ◽  
L. A. Lee ◽  
C. L. Reddington ◽  
K. S. Carslaw
Keyword(s):  
Nucleation Rate ◽  
Atmospheric Aerosols ◽  
Large Scale ◽  
Cloud Condensation Nuclei ◽  
Cosmic Ray ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Significant Response ◽  
Short Term ◽  
Aerosol Properties

Abstract. Observed correlations between short-term decreases in cosmic ray ionisation and cloud and aerosol properties have been attributed to short-term decreases in the ion-induced nucleation rate. We use a global aerosol microphysics model to determine whether a 10-day reduction of 15% in the nucleation rate could generate a statistically significant response in aerosol concentrations and optical properties. As an upper limit to the possible effect of changes in the ion-induced nucleation rate, we perturb the total nucleation rate, which has been shown to generate particle concentrations and nucleation events in reasonable agreement with global observations. When measured against a known aerosol control state, the model predicts a 0.15% decrease in global mean cloud condensation nucleus concentrations at the surface. However, taking into account the variability in aerosol, no statistically significant response can be detected in concentrations of particles with diameters larger than 10 nm, in cloud condensation nuclei with diameters larger than 70 nm, or in the Ångström exponent. The results suggest that the observed correlation between short-term decreases in cosmic ray ionisation and cloud and aerosol properties cannot be explained by associated changes in the large-scale nucleation rate.

scholarly journals Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material

2013 ◽  
Vol 13 (11) ◽  
pp. 31041-31078 ◽  
Author(s):  
S. Garimella ◽  
Y.-w. Huang ◽  
J. S. Seewald ◽  
D. J. Cziczo
Keyword(s):  
Clay Mineral ◽  
Cloud Condensation Nuclei ◽  
Particle Surface ◽  
Droplet Formation ◽  
Cloud Condensation Nucleus ◽  
Condensation Nuclei ◽  
Mineral Particles ◽  
Multiply Charged ◽  
Kohler Theory ◽  
Soluble Material

Abstract. This study examines the interaction of clay mineral particles and water vapor to determine the conditions required for cloud droplet formation. Droplet formation conditions are investigated for three clay minerals: illite, sodium-rich montmorillonite, and Arizona Test Dust. Using wet and dry particle generation coupled to a differential mobility analyzer (DMA) and cloud condensation nuclei counter, the critical activation of the clay mineral particles as cloud condensation nuclei is characterized. Electron microscopy (EM) is used to determine non-sphericity in particle shape. EM is also used to determine particle surface area and account for transmission of multiply charged particles by the DMA. Single particle mass spectrometry and ion chromatography are used to investigate soluble material in wet-generated samples and demonstrate that wet and dry generation yield compositionally different particles. Activation results are analyzed in the context of both κ-Köhler theory and Frenkel, Halsey, and Hill (FHH) adsorption activation theory. This study has two main results: (1) κ-Köhler is a suitable framework, less complex than FHH theory, to describe clay mineral nucleation activity despite apparent differences in κ with respect to size. For dry-generated particles the size dependence is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle concentration at ~300 nm, and a large fraction of particles classified with a mobility diameter less than ~300 nm are actually multiply charged, resulting in a much lower critical supersaturation for droplet activation than expected. For wet-generated particles, deviation from κ-Köhler theory is likely a result of the dissolution and redistribution of soluble material. (2) Wet-generation is found to be unsuitable for simulating the lofting of fresh dry dust because it changes the size-dependent critical supersaturations by fractionating and re-partitioning soluble material.

scholarly journals Dust mass, cloud condensation nuclei, and ice-nucleating particle profiling with polarization lidar: updated POLIPHON conversion factors from global AERONET analysis

2019 ◽  
Vol 12 (9) ◽  
pp. 4849-4865 ◽  
Author(s):  
Albert Ansmann ◽  
Rodanthi-Elisavet Mamouri ◽  
Julian Hofer ◽  
Holger Baars ◽  
Dietrich Althausen ◽  
...  
Keyword(s):  
Surface Area ◽  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Conversion Factors ◽  
Microphysical Properties ◽  
Central Asian ◽  
Volume Forms ◽  
Aerosol Type

Abstract. The POLIPHON (Polarization Lidar Photometer Networking) method permits the retrieval of particle number, surface area, and volume concentration for dust and non-dust aerosol components. The obtained microphysical properties are used to estimate height profiles of particle mass, cloud condensation nucleus (CCN) and ice-nucleating particle (INP) concentrations. The conversion of aerosol-type-dependent particle extinction coefficients, derived from polarization lidar observations, into the aerosol microphysical properties (number, surface area, volume) forms the central part of the POLIPHON computations. The conversion parameters are determined from Aerosol Robotic Network (AERONET) aerosol climatologies of optical and microphysical properties. In this article, we focus on the dust-related POLIPHON retrieval products and present an extended set of dust conversion factors considering all relevant deserts around the globe. We apply the new conversion factor set to a dust measurement with polarization lidar in Dushanbe, Tajikistan, in central Asia. Strong aerosol layering was observed with mineral dust advected from Kazakhstan (0–2 km height), Iran (2–5 km), the Arabian peninsula (5–7 km), and the Sahara (8–10 km). POLIPHON results obtained with different sets of conversion parameters were contrasted in this central Asian case study and permitted an estimation of the conversion uncertainties.

scholarly journals A single parameter representation of hygroscopic growth and cloud condensation nucleus activity

2007 ◽  
Vol 7 (8) ◽  
pp. 1961-1971 ◽  
Author(s):  
M. D. Petters ◽  
S. M. Kreidenweis
Keyword(s):  
Compositional Data ◽  
Cloud Condensation Nuclei ◽  
Condensation Nucleus ◽  
Atmospheric Particulate Matter ◽  
Cloud Condensation Nucleus ◽  
Hygroscopic Growth ◽  
Activation Data ◽  
Surface Active ◽  
Surface Active Compounds ◽  
Ccn Activity

Abstract. We present a method to describe the relationship between particle dry diameter and cloud condensation nuclei (CCN) activity using a single hygroscopicity parameter κ. Values of the hygroscopicity parameter are between 0.5 and 1.4 for highly-CCN-active salts such as sodium chloride, between 0.01 and 0.5 for slightly to very hygroscopic organic species, and 0 for nonhygroscopic components. Observations indicate that atmospheric particulate matter is typically characterized by 0.1<κ<0.9. If compositional data are available and if the hygroscopicity parameter of each component is known, a multicomponent hygroscopicity parameter can be computed by weighting component hygroscopicity parameters by their volume fractions in the mixture. In the absence of information on chemical composition, experimental data for complex, multicomponent particles can be fitted to obtain the hygroscopicity parameter. The hygroscopicity parameter can thus also be used to conveniently model the CCN activity of atmospheric particles, including those containing insoluble components. We confirm the applicability of the hygroscopicity parameter and its mixing rule by applying it to published hygroscopic diameter growth factor and CCN-activation data for single- and multi-component particles containing varying amounts of inorganic, organic and surface active compounds. We suggest that κ may be fit to CCN data assuming σs/a=0.072 J m−2 and present a table of κ derived for this value and T=298.15 K. The predicted hygroscopicities for mixtures that contain the surfactant fulvic acid agree within uncertainties with the measured values. It thus appears that this approach is adequate for predicting CCN activity of mixed particles containing surface active materials, but the generality of this assumption requires further verification.

scholarly journals A single parameter representation of hygroscopic growth and cloud condensation nucleus activity – Part 3: Including surfactant partitioning

2012 ◽  
Vol 12 (9) ◽  
pp. 22687-22712 ◽  
Author(s):  
M. D. Petters ◽  
S. M. Kreidenweis
Keyword(s):  
Cloud Condensation Nuclei ◽  
Cloud Droplet ◽  
Condensation Nucleus ◽  
Single Parameter ◽  
Cloud Condensation Nucleus ◽  
Extended Model ◽  
Hygroscopic Growth ◽  
Analytical Approximations ◽  
Critical Supersaturation ◽  
Kohler Theory

Abstract. Atmospheric particles can serve as cloud condensation nuclei in the atmosphere. The presence of surface active compounds in the particle may affect the critical supersaturation that is required to activate a particle. Modelling surfactants in the context of Köhler theory, however, is difficult because surfactant enrichment at the surface implies that a stable radial concentration gradient must exist in the droplet. In this study, we introduce a hybrid model that accounts for partitioning between the bulk and surface phases in the context of single parameter representations of cloud condensation nucleus activity. The presented formulation incorporates the analytical approximations introduced by Raatikainen and Laaksonen to yield a set of equations that maintain the conceptual and mathematical simplicity of the single parameter framework. The resulting set of equations allows users of the single parameter model to account for surfactant partitioning by applying minor modifications to already existing code. We apply this extended model to discuss several uncertainties that hinder our ability to precisely pinpoint the role of surface tension in cloud droplet activation with current measurement and data analysis approaches.

scholarly journals No statistically significant effect of a short-term decrease in the nucleation rate on atmospheric aerosols

2012 ◽  
Vol 12 (23) ◽  
pp. 11573-11587 ◽  
Author(s):  
E. M. Dunne ◽  
L. A. Lee ◽  
C. L. Reddington ◽  
K. S. Carslaw
Keyword(s):  
Nucleation Rate ◽  
Atmospheric Aerosols ◽  
Large Scale ◽  
Cloud Condensation Nuclei ◽  
Cosmic Ray ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Significant Response ◽  
Short Term ◽  
Aerosol Properties

Abstract. Observed correlations between short-term decreases in cosmic ray ionisation and cloud and aerosol properties have been attributed to short-term decreases in the ion-induced nucleation rate. We use a global aerosol microphysics model to determine whether a 10 day reduction of 15% in the nucleation rate could generate a statistically significant response in aerosol concentrations and optical properties. As an upper limit to the possible effect of changes in ion-induced nucleation rate, we perturb the total nucleation rate, which has been shown to generate particle concentrations and nucleation events in reasonable agreement with global observations. When measured against a known aerosol control state, the model predicts a 0.15% decrease in global mean cloud condensation nucleus concentration at the surface. However, taking into account the variability in aerosol, no statistically significant response can be detected in concentrations of particles with diameters larger than 10 nm, in cloud condensation nuclei with diameters larger than 70 nm, or in the Ångström exponent. The results suggest that the observed correlation between short-term decreases in cosmic ray ionisation and cloud and aerosol properties cannot be explained by associated changes in the large-scale nucleation rate.

scholarly journals A single parameter representation of hygroscopic growth and cloud condensation nucleus activity

2006 ◽  
Vol 6 (5) ◽  
pp. 8435-8456 ◽  
Author(s):  
M. D. Petters ◽  
S. M. Kreidenweis
Keyword(s):  
Compositional Data ◽  
Cloud Condensation Nuclei ◽  
Particle Diameter ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Hygroscopic Growth ◽  
General Applicability ◽  
Activation Data ◽  
Parameter Values ◽  
Ccn Activity

Abstract. We present a method to describe the relationship between dry particle diameter and cloud condensation nuclei (CCN) activity using a single hygroscopicity parameter. Values of the hygroscopicity parameter are between 0.5 and 2 for highly-CCN-active salts such as sodium chloride, between 0.01 and 0.5 for slightly to very hygroscopic organic species, and 0 for nonhygroscopic components. If compositional data are available and if the hygroscopicity parameter of each component is known, a multicomponent hygroscopicity parameter can be computed by weighting component hygroscopicity parameters by their volume fractions in the mixture. In the absence of information on chemical composition, experimental data for complex, multicomponent particles can be fitted to obtain the hygroscopicity parameter. The hygroscopicity parameter can thus also be used to conveniently model the CCN activity of atmospheric particles, including those containing insoluble components. We confirm the general applicability of the hygroscopicity parameter and its mixing rule by applying it to published hygroscopic diameter growth factor and CCN-activation data for single- and multi-component particles.

scholarly journals Aerosol- and updraft-limited regimes of cloud droplet formation: influence of particle number, size and hygroscopicity on the activation of cloud condensation nuclei (CCN)

2009 ◽  
Vol 9 (2) ◽  
pp. 8635-8665 ◽  
Author(s):  
P. Reutter ◽  
J. Trentmann ◽  
H. Su ◽  
M. Simmel ◽  
D. Rose ◽  
...  
Keyword(s):  
Particle Number ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Cloud Droplet ◽  
Condensation Nucleus ◽  
Droplet Formation ◽  
Cloud Condensation Nucleus ◽  
Aerosol Size Distribution ◽  
Cloud Base ◽  
Wide Range

Abstract. We have investigated the formation of cloud droplets under (pyro-)convective conditions using a cloud parcel model with detailed spectral microphysics and with the κ-Köhler model approach for efficient and realistic description of the cloud condensation nucleus (CCN) activity of aerosol particles. Assuming a typical biomass burning aerosol size distribution (accumulation mode centred at 120 nm), we have calculated initial cloud droplet number concentrations (NCD) for a wide range of updraft velocities (w=0.5–20 m s−1) and aerosol particle number concentrations (NCN=103–105 cm−3) at the cloud base. Depending on the ratio between updraft velocity and particle number concentration (w/NCN), we found three distinctly different regimes of CCN activation and cloud droplet formation: 1. An aerosol-limited regime that is characterized by high w/NCN ratios (>≈10−3 m s−1 cm3), high maximum values of water vapour supersaturation (Smax>≈0.5%), and high activated fractions of aerosol particles (NCD/NCN>≈90%). In this regime NCD is directly proportional to NCN and practically independent of w. 2. An updraft-limited regime that is characterized by low w/NCN ratios (

scholarly journals Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol: the significance of soluble material

2014 ◽  
Vol 14 (12) ◽  
pp. 6003-6019 ◽  
Author(s):  
S. Garimella ◽  
Y.-W. Huang ◽  
J. S. Seewald ◽  
D. J. Cziczo
Keyword(s):  
Clay Mineral ◽  
Cloud Condensation Nuclei ◽  
Particle Surface ◽  
Droplet Formation ◽  
Cloud Condensation Nucleus ◽  
Dust Particles ◽  
Condensation Nuclei ◽  
Mineral Particles ◽  
Multiply Charged ◽  
Soluble Material

Abstract. This study examines the interaction of clay mineral particles and water vapor for determining the conditions required for cloud droplet formation. Droplet formation conditions are investigated for two common clay minerals, illite and sodium-rich montmorillonite, and an industrially derived sample, Arizona Test Dust. Using wet and dry particle generation coupled to a differential mobility analyzer (DMA) and cloud condensation nuclei counter, the critical activation of the clay mineral particles as cloud condensation nuclei is characterized. Electron microscopy (EM) is used in order to determine non-sphericity in particle shape. It is also used in order to determine particle surface area and account for transmission of multiply charged particles by the DMA. Single particle mass spectrometry and ion chromatography are used to investigate soluble material in wet-generated samples and demonstrate that wet and dry generation yield compositionally different particles. Activation results are analyzed in the context of both κ-Köhler theory (κ-KT) and Frenkel–Halsey–Hill (FHH) adsorption activation theory. This study has two main results: (1) κ-KT is the suitable framework to describe clay mineral nucleation activity. Apparent differences in κ with respect to size arise from an artifact introduced by improper size-selection methodology. For dust particles with mobility sizes larger than ~300 nm, i.e., ones that are within an atmospherically relevant size range, both κ-KT and FHH theory yield similar critical supersaturations. However, the former requires a single hygroscopicity parameter instead of the two adjustable parameters required by the latter. For dry-generated particles, the size dependence of κ is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle concentration at ~300 nm, and a large fraction of particles classified with a mobility diameter less than ~300 nm are actually multiply charged, resulting in a much lower critical supersaturation for droplet activation than expected. For wet-generated particles, deviation from κ-KT is likely a result of the dissolution and redistribution of soluble material. (2) Wet generation is found to be unsuitable for simulating the lofting of fresh dry dust because it changes the size-dependent critical supersaturations by fractionating and re-partitioning soluble material.

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