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

Paramonov, M. ; Kerminen, V. -M. ; Gysel, M. ; Aalto, P. P. ; Andreae, M. O. ; Asmi, E. ; Baltensperger, U. ; Bougiatioti, A. ; Brus, D. and Frank, Göran LU orcid , et al. (2015) In Atmospheric Chemistry and Physics 15(21). p.12211-12229
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 (N-CCN) to the total number concentration of particles (N-CN), 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... (More)
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 (N-CCN) to the total number concentration of particles (N-CN), 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 (A(50) and A(100), respectively) renders a much more stable dependence of A on S; A(50) and A(100) 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 kappa 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 kappa increased with size. In fact, in Hyytiala, 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 kappa can lead to a potentially substantial overestimation of N-CCN at S levels above 0.6 %. The same is true for other locations where kappa was found to increase with size. While detailed information about aerosol hygroscopicity can significantly improve the prediction of N-CCN, 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. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Atmospheric Chemistry and Physics
volume
15
issue
21
pages
12211 - 12229
publisher
Copernicus GmbH
external identifiers
  • wos:000365329000006
  • scopus:84946238238
ISSN
1680-7324
DOI
10.5194/acp-15-12211-2015
language
English
LU publication?
yes
id
e98bccbb-5e10-440f-9ffd-3b10b6c6f182 (old id 8539805)
date added to LUP
2016-04-01 10:58:48
date last changed
2022-02-10 07:46:03
@article{e98bccbb-5e10-440f-9ffd-3b10b6c6f182,
  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 (N-CCN) to the total number concentration of particles (N-CN), 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 (A(50) and A(100), respectively) renders a much more stable dependence of A on S; A(50) and A(100) 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 kappa 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 kappa increased with size. In fact, in Hyytiala, 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 kappa can lead to a potentially substantial overestimation of N-CCN at S levels above 0.6 %. The same is true for other locations where kappa was found to increase with size. While detailed information about aerosol hygroscopicity can significantly improve the prediction of N-CCN, 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.}},
  author       = {{Paramonov, M. and Kerminen, V. -M. and Gysel, M. and Aalto, P. P. and Andreae, M. O. and Asmi, E. and Baltensperger, U. and Bougiatioti, A. and Brus, D. and Frank, Göran and Good, N. and Gunthe, S. S. and Hao, L. and Irwin, M. and Jaatinen, A. and Juranyi, Z. and King, S. M. and Kortelainen, A. and Kristensson, Adam and Lihavainen, H. and Kulmala, M. and Lohmann, U. and Martin, S. T. and McFiggans, G. and Mihalopoulos, N. and Nenes, A. and O'Dowd, C. D. and Ovadnevaite, J. and Petaja, T. and Poschl, U. and Roberts, G. C. and Rose, D. and Svenningsson, B. and Swietlicki, Erik and Weingartner, E. and Whitehead, J. and Wiedensohler, A. and Wittbom, C. and Sierau, B.}},
  issn         = {{1680-7324}},
  language     = {{eng}},
  number       = {{21}},
  pages        = {{12211--12229}},
  publisher    = {{Copernicus GmbH}},
  series       = {{Atmospheric Chemistry and Physics}},
  title        = {{A synthesis of cloud condensation nuclei counter (CCNC) measurements within the EUCAARI network}},
  url          = {{http://dx.doi.org/10.5194/acp-15-12211-2015}},
  doi          = {{10.5194/acp-15-12211-2015}},
  volume       = {{15}},
  year         = {{2015}},
}