Use of in situ cloud condensation nuclei, extinction, and aerosol size distribution measurements to test a method for retrieving cloud condensation nuclei profiles from surface measurements

Abstract. Measurements of cloud condensation nuclei (CCN) concentrations (cm−3) between 0.2 and 1.0% supersaturation, aerosol size distribution and chemical composition were performed at a remote marine site in the eastern Mediterranean, from September to October 2007 during the FAME07 campaign. Most of the particles activate at ~0.6% supersaturation, characteristic of the aged nature of the aerosol sampled. Application of Köhler theory, using measurements of bulk composition, size distribution, and assuming that organics are insoluble resulted in agreement between predicted and measured CCN concentrations within 7±11% for all supersaturations, with a tendency for CCN underprediction (16±6%; r2=0.88) at the lowest supersaturations (0.21%). Including the effects of the water-soluble organic fraction (which represent around 70% of the total organic content) reduces the average underprediction bias at the low supersaturations, resulting in a total closure error of 0.6±6%. Using threshold droplet growth analysis, the growth kinetics of ambient CCN is consistent with NaCl calibration experiments; hence the presence of aged organics does not suppress the rate of water uptake in this environment. The knowledge of the soluble salt fraction is sufficient for the description of the CCN activity in this area.

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On aerosol hygroscopicity, cloud condensation nuclei (CCN) spectra and critical supersaturation measured at two remote islands of Korea between 2006 and 2009

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-19683-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 19683-19727 ◽

Cited By ~ 2

Author(s):

J. H. Kim ◽

S. S. Yum ◽

S. Shim ◽

S.-C. Yoon ◽

J. G. Hudson ◽

...

Keyword(s):

Size Distribution ◽

Total Concentration ◽

Cloud Condensation Nuclei ◽

Geometric Mean ◽

Aerosol Size Distribution ◽

Monitoring Site ◽

Hygroscopic Growth ◽

Condensation Nuclei ◽

Critical Supersaturation ◽

Aerosol Hygroscopicity

Abstract. Aerosol size distribution, total concentration (i.e., condensation nuclei (CN) concentration, NCN), cloud condensation nuclei (CCN) concentration (NCCN), hygroscopicity at ~90 % relative humidity (RH) were measured at a background monitoring site at Gosan, Jeju Island, south of the Korea Peninsula in August 2006, April to May 2007 and August to October 2008. Similar measurement took place in August 2009 at another background site (Baengnyeongdo Comprehensive Monitoring Observatory, BCMO) on the island of Baengnyeongdo, off the west coast of the Korean Peninsula. Both islands were found to be influenced by continental sources regardless of season and year. Average values for all of the measured NCCN at 0.2, 0.6 and 1.0 % supersaturations (S), NCN, and geometric mean diameter (Dg) from both islands were in the range of 1043–3051 cm−3, 2076–4360 cm−3, 2713–4694 cm−3, 3890–5117 cm−3 and 81–98 nm, respectively. Although the differences in Dg and NCN were small between Gosan and BCMO, NCCN at various S was much higher at the latter, which is closer to China. Most of the aerosols were internally mixed and no notable differences in hygroscopicity were found between the days of strong pollution influence and the non-pollution days for both islands. During the 2008 and 2009 campaigns, critical supersaturation for cloud nucleation (Sc) for selected particle sizes was measured. Particles of 100 nm diameters had mean Sc of 0.19 ± 0.02 % during 2008 and those of 81 and 110 nm diameters had mean Sc of 0.26 ± 0.07 % and 0.17 ± 0.04 %, respectively, during 2009. Hygroscopicity parameters estimated from the measured Sc were mostly higher than the ones from the measured hygroscopic growth at ~90 % RH. For the 2008 campaign, NCCN at 0.2, 0.6 and 1.0 % S were predicted based on the measured dry particle size distribution and various ways of representing aerosol hygroscopicity. The best closure was obtained when temporally varying and size-resolved hygroscopicity information from HTDMA was used, for which the average relative deviations from the measured values were 19 % for 1.0 % S and 28 % for 0.2 % S. Prescribing a constant hygroscopicity parameter suggested in literature (κ = 0.3) for all sizes and time resulted in the average relative deviations, 25–40 %. When constant hygroscopicity was assumed, the relative deviation tended to increase with decreasing NCCN, which was accompanied by increase of sub-100 nm fraction. These results suggest that hygroscopicity information for aerosols of diameters smaller than 100 nm is crucial for more accurate prediction of NCCN.

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Impact of aerosol composition on cloud condensation nuclei activity

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-3783-2012 ◽

2012 ◽

Vol 12 (8) ◽

pp. 3783-3790 ◽

Cited By ~ 28

Author(s):

Q. Zhang ◽

J. Meng ◽

J. Quan ◽

Y. Gao ◽

D. Zhao ◽

...

Keyword(s):

Size Distribution ◽

Field Experiments ◽

Cloud Condensation Nuclei ◽

Diffusion Chamber ◽

Aerosol Size Distribution ◽

Condensation Nuclei ◽

Aerosol Composition ◽

Rate Of Increase ◽

The Impact ◽

Ccn Activity

Abstract. The impact of aerosol composition on cloud condensation nuclei (CCN) activity were analyzed in this study based on field experiments carried out at downtown Tianjin, China in September 2010. In the experiments, the CCN measurements were performed at supersaturation (SS) of 0.1%, 0.2% and 0.4% using a thermal-gradient diffusion chamber (DMT CCNC), whereas the aerosol size distribution and composition were simultaneously measured with a TSI SMPS and an Aerodyne Aerosol Mass Spectrometer (AMS), respectively. The results show that the influence of aerosol composition on CCN activity is notable under low SS (0.1%), and their influence decreased with increasing SS. For example, under SS of 0.1%, the CCN activity increases from 4.5±2.6% to 12.8±6.1% when organics fraction decrease from 30–40% to 10–20%. The rate of increase reached up to 184%. While under SS of 0.4%, the CCN activity increases only from 35.7±19.0% to 46.5±12.3% correspondingly. The calculated NCCN based on the size-resolved activation ratio and aerosol number size distribution correlated well with observed NCCN at high SS (0.4%), but this consistence decreased with the falling of SS. The slopes of linear fitted lines between calculated and observed NCCN are 0.708, 0.947, and 0.995 at SS of 0.1%, 0.2% and 0.4% respectively. Moreover, the stand deviation (SD) of calculated NCCN increased with the decreasing of SS. A case study of CCN closure analyses indicated that the calculated error of NCCN could reach up to 34% at SS of 0.1% if aerosol composition were not included, and the calculated error decreased with the raising of SS. It is decreased to 9% at SS of 0.2%, and further decreased to 4% at SS of 0.4%.

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Long-term observations of cloud condensation nuclei in the Amazon rain forest – Part 1: Aerosol size distribution, hygroscopicity, and new model parametrizations for CCN prediction

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-15709-2016 ◽

2016 ◽

Vol 16 (24) ◽

pp. 15709-15740 ◽

Cited By ~ 45

Author(s):

Mira L. Pöhlker ◽

Christopher Pöhlker ◽

Florian Ditas ◽

Thomas Klimach ◽

Isabella Hrabe de Angelis ◽

...

Keyword(s):

Size Distribution ◽

Aerosol Particle ◽

Rain Forest ◽

Seasonal Cycle ◽

Cloud Condensation Nuclei ◽

Number Concentration ◽

Aerosol Size Distribution ◽

Condensation Nuclei ◽

Central Amazon

Abstract. Size-resolved long-term measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted at the remote Amazon Tall Tower Observatory (ATTO) in the central Amazon Basin over a 1-year period and full seasonal cycle (March 2014–February 2015). The measurements provide a climatology of CCN properties characteristic of a remote central Amazonian rain forest site.The CCN measurements were continuously cycled through 10 levels of supersaturation (S  =  0.11 to 1.10 %) and span the aerosol particle size range from 20 to 245 nm. The mean critical diameters of CCN activation range from 43 nm at S  =  1.10 % to 172 nm at S  =  0.11 %. The particle hygroscopicity exhibits a pronounced size dependence with lower values for the Aitken mode (κAit  =  0.14 ± 0.03), higher values for the accumulation mode (κAcc  =  0.22 ± 0.05), and an overall mean value of κmean  =  0.17 ± 0.06, consistent with high fractions of organic aerosol.The hygroscopicity parameter, κ, exhibits remarkably little temporal variability: no pronounced diurnal cycles, only weak seasonal trends, and few short-term variations during long-range transport events. In contrast, the CCN number concentrations exhibit a pronounced seasonal cycle, tracking the pollution-related seasonality in total aerosol concentration. We find that the variability in the CCN concentrations in the central Amazon is mostly driven by aerosol particle number concentration and size distribution, while variations in aerosol hygroscopicity and chemical composition matter only during a few episodes.For modeling purposes, we compare different approaches of predicting CCN number concentration and present a novel parametrization, which allows accurate CCN predictions based on a small set of input data.

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A synthesis of cloud condensation nuclei counter (CCNC) measurements within the EUCAARI network

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-12211-2015 ◽

2015 ◽

Vol 15 (21) ◽

pp. 12211-12229 ◽

Cited By ~ 21

Author(s):

M. Paramonov ◽

V.-M. Kerminen ◽

M. Gysel ◽

P. P. Aalto ◽

M. O. Andreae ◽

...

Keyword(s):

Size Distribution ◽

Cloud Condensation Nuclei ◽

Number Concentration ◽

West Germany ◽

Aerosol Size Distribution ◽

Spatial And Temporal Variability ◽

Condensation Nuclei ◽

Aerosol Cloud ◽

Hygroscopic Properties ◽

South West

Abstract. Cloud condensation nuclei counter (CCNC) measurements performed at 14 locations around the world within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) framework have been analysed and discussed with respect to the cloud condensation nuclei (CCN) activation and hygroscopic properties of the atmospheric aerosol. The annual mean ratio of activated cloud condensation nuclei (NCCN) to the total number concentration of particles (NCN), known as the activated fraction A, shows a similar functional dependence on supersaturation S at many locations – exceptions to this being certain marine locations, a free troposphere site and background sites in south-west Germany and northern Finland. The use of total number concentration of particles above 50 and 100 nm diameter when calculating the activated fractions (A50 and A100, respectively) renders a much more stable dependence of A on S; A50 and A100 also reveal the effect of the size distribution on CCN activation. With respect to chemical composition, it was found that the hygroscopicity of aerosol particles as a function of size differs among locations. The hygroscopicity parameter κ decreased with an increasing size at a continental site in south-west Germany and fluctuated without any particular size dependence across the observed size range in the remote tropical North Atlantic and rural central Hungary. At all other locations κ increased with size. In fact, in Hyytiälä, Vavihill, Jungfraujoch and Pallas the difference in hygroscopicity between Aitken and accumulation mode aerosol was statistically significant at the 5 % significance level. In a boreal environment the assumption of a size-independent κ can lead to a potentially substantial overestimation of NCCN at S levels above 0.6 %. The same is true for other locations where κ was found to increase with size. While detailed information about aerosol hygroscopicity can significantly improve the prediction of NCCN, total aerosol number concentration and aerosol size distribution remain more important parameters. The seasonal and diurnal patterns of CCN activation and hygroscopic properties vary among three long-term locations, highlighting the spatial and temporal variability of potential aerosol–cloud interactions in various environments.

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Impact of aerosol composition on cloud condensation nuclei activity

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-1493-2012 ◽

2012 ◽

Vol 12 (1) ◽

pp. 1493-1516

Author(s):

Q. Zhang ◽

J. Meng ◽

J. Quan ◽

Y. Gao ◽

D. Zhao ◽

...

Keyword(s):

Size Distribution ◽

Field Experiments ◽

Cloud Condensation Nuclei ◽

Diffusion Chamber ◽

Aerosol Size Distribution ◽

Condensation Nuclei ◽

Aerosol Composition ◽

Rate Of Increase ◽

The Impact ◽

Ccn Activity

Abstract. The impact of aerosol composition on cloud condensation nuclei (CCN) activity was analyzed in this study based on field experiments carried out at downtown Tianjin, China, in September 2010. In the experiments, the CCN measurements were performed at supersaturation (SS) of 0.1%, 0.2% and 0.4% using a thermal-gradient diffusion chamber (DMT CCNC), whereas the aerosol size distribution and composition were simultaneously measured with a TSI SMPS and an Aerodyne Aerosol Mass Spectrometer (AMS), respectively. The results show that the influence of aerosol composition on CCN activity is notable under low SS (0.1%), and their influence decreased with increasing SS. For example, under SS of 0.1%, the CCN activity increases from 4.5 ± 2.6% to 12.8 ± 6.1% when organics fraction decrease from 30–40% to 10–20%. The rate of increase reaches up to 184%. While under SS of 0.4%, the CCN activity increases only from 35.7 ± 19.0% to 46.5 ± 12.3%, correspondingly. The calculated NCCN based on the size-resolved activation ratio and aerosol number size distribution correlates well with observed NCCN at high SS (0.4%), but this correlation decreases with the falling of SS. The slopes of linear fitted lines between calculated and observed NCCN are 0.708, 0.947, and 0.995 at SS of 0.1%, 0.2% and 0.4%, respectively. Moreover, the standard deviation (SD) of calculated NCCN increases with the decreasing of SS. A case study of CCN closure analyses indicates that the calculated error of NCCN can reach up to 34% at SS of 0.1% if aerosol composition is not included, and the calculated error decreases with the raising of SS. It decreases to 9% at SS of 0.2%, and further decreases to 4% at SS of 0.4%.

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Efficiency of cloud condensation nuclei formation from ultrafine particles

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-1367-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 1367-1379 ◽

Cited By ~ 143

Author(s):

J. R. Pierce ◽

P. J. Adams

Keyword(s):

Size Distribution ◽

Ultrafine Particles ◽

Particle Deposition ◽

Cloud Condensation Nuclei ◽

Large Fraction ◽

Ultrafine Particle ◽

Aerosol Size Distribution ◽

Condensation Nuclei ◽

Anthropogenic Aerosol ◽

Different Parts

Abstract. Atmospheric cloud condensation nuclei (CCN) concentrations are a key uncertainty in the assessment of the effect of anthropogenic aerosol on clouds and climate. The ability of new ultrafine particles to grow to become CCN varies throughout the atmosphere and must be understood in order to understand CCN formation. We have developed the Probability of Ultrafine particle Growth (PUG) model to answer questions regarding which growth and sink mechanisms control this growth, how the growth varies between different parts of the atmosphere and how uncertainties with respect to the magnitude and size distribution of ultrafine emissions translates into uncertainty in CCN generation. The inputs to the PUG model are the concentrations of condensable gases, the size distribution of ambient aerosol, particle deposition timescales and physical properties of the particles and condensable gases. It was found in most cases that condensation is the dominant growth mechanism and coagulation with larger particles is the dominant sink mechanism for ultrafine particles. In this work we found that the probability of a new ultrafine particle generating a CCN varies from <0.1% to ~90% in different parts of the atmosphere, though in the boundary layer a large fraction of ultrafine particles have a probability between 1% and 40%. Some regions, such as the tropical free troposphere, are areas with high probabilities; however, variability within regions makes it difficult to predict which regions of the atmosphere are most efficient for generating CCN from ultrafine particles. For a given mass of primary ultrafine aerosol, an uncertainty of a factor of two in the modal diameter can lead to an uncertainty in the number of CCN generated as high as a factor for eight. It was found that no single moment of the primary aerosol size distribution, such as total mass or number, is a robust predictor of the number of CCN ultimately generated. Therefore, a complete description of the emissions size distribution is generally required for global aerosol microphysics models.

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On the Contrast of Aerosol Size Distribution and Cloud Condensation Nuclei Concentrations between the East and the West of the Korean Peninsula

Atmosphere ◽

10.14191/atmos.2012.22.1.087 ◽

2012 ◽

Vol 22 (1) ◽

pp. 87-96 ◽

Cited By ~ 3

Author(s):

Jong Hwan Kim ◽

Min-Su Park ◽

Sungbo Shim ◽

Seong Soo Yum

Keyword(s):

Size Distribution ◽

Korean Peninsula ◽

Cloud Condensation Nuclei ◽

Aerosol Size Distribution ◽

Condensation Nuclei ◽

The West

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Retrieving cloud condensation nuclei concentrations from spaceborne lidar measurements

10.5194/egusphere-egu21-2598 ◽

2021 ◽

Author(s):

Goutam Choudhury ◽

Matthias Tesche

Keyword(s):

Size Distribution ◽

Extinction Coefficient ◽

Climate Models ◽

Cloud Condensation Nuclei ◽

In Situ Measurements ◽

Satellite Observations ◽

Spherical Particles ◽

Condensation Nuclei ◽

Volume Size

<p>Aerosols interact with atmospheric radiation either directly through scattering and absorption or indirectly by acting as cloud condensation nuclei (CCN) and ice nucleating particles (INP), thereby altering cloud properties. The latter aerosol-cloud interaction (ACI) effects are still poorly understood and believed to be one of the key uncertainties in climate models. In the present scenario, the observations of CCN are still sparse as in-situ measurements are expensive and often restricted to specific locations and limited time periods. An alternative is to turn to satellite observations for ACI studies. The Cloud Aerosol Lidar with Orthogonal Polarisation (CALIOP) is a spaceborne lidar aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. It provides high-resolution vertical profiles of aerosol related parameters such as the aerosol extinction coefficient, backscatter coefficient, aerosol subtypes, and depolarization ratio. In order to estimate the CCN concentrations, we use these parameters along with the normalised lognormal bimodal volume size distributions and complex refractive indices of different aerosol subtypes given in the CALISPO aerosol model.</p><p>&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; The normalised size distribution, the refractive index and the relative humidity are first used to compute the extinction coefficient using the MOPSMAP package. For this, all the aerosol types are treated as spherical particles except the dust which is treated as spheroid. The size distribution is then modified until the estimated extinction agrees with that measured by the CALIPSO. The modified size distribution is integrated to compute the number concentration of aerosols that form the favourable CCN reservoir. To estimate the uncertainty in the retrieval algorithm, we performed the sensitivity analysis by varying the initial normalised volume size distribution by up to +/- 50 % for each mode (fine and coarse). The results are presented as case studies with some preliminary validation against in-situ measurements. The purpose of this work is to obtain a global 3D CCN climatology for use in ACI studies and improving the performance of the global climate models.</p>

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A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-179-2005 ◽

2005 ◽

Vol 5 (1) ◽

pp. 179-215 ◽

Cited By ~ 12

Author(s):

D. V. Spracklen ◽

K. J. Pringle ◽

K. S. Carslaw ◽

M. P. Chipperfield ◽

G. W. Mann

Keyword(s):

Boundary Layer ◽

Sulfuric Acid ◽

Size Distribution ◽

Marine Boundary Layer ◽

Transport Model ◽

Cloud Condensation Nuclei ◽

Aerosol Size Distribution ◽

Sea Spray ◽

Condensation Nuclei ◽

Upper Troposphere

Abstract. A GLObal Model of Aerosol Processes (GLOMAP) has been developed as an extension to the TOMCAT 3-D Eulerian off-line chemical transport model. GLOMAP simulates the evolution of the global aerosol size distribution using a sectional two-moment scheme and includes the processes of aerosol nucleation, condensation, growth, coagulation, wet and dry deposition and cloud processing. We describe the results of a global simulation of sulfuric acid and sea spray aerosol. The model captures features of the aerosol size distribution that are well established from observations in the marine boundary layer and free troposphere. Modelled condensation nuclei (CN>3 nm) vary between about 250–500 cm-3 in remote marine boundary layer regions and between 2000 and 10 000 cm-3 (at standard temperature and pressure) in the upper troposphere. Cloud condensation nuclei (CCN) at 0.2% supersaturation vary between about 1000 cm-3 in polluted regions and between 10 and 500 cm-3 in the remote marine boundary layer. New particle formation through sulfuric acid-water binary nucleation occurs predominantly in the upper troposphere, but the model results show that these particles contribute greatly to aerosol concentrations in the marine boundary layer. It is estimated that sea spray emissions account for only ~10% of CCN in the tropical marine boundary layer, but between 20 and 75% in the mid-latitude Southern Ocean.

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