Results from the CERN pilot CLOUD experiment

During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible
During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm -3 s -1, and growth rates between 2 and 37 nm h -1. The corresponding H2O concentrations were typically around 106 cm -3 or less. The experimentally-measured formation rates and htwosofour concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C)
show moreshow less

Download full text files

Export metadata

  • Export Bibtex
  • Export RIS

Additional Services

    Share in Twitter Search Google Scholar
Metadaten
Author:Jonathan Duplissy, Martin Bødker Enghoff, Karen L. Aplin, Frank Arnold, Heinfried Aufmhoff, Michael Avngaard, Urs Baltensperger, Torsten Bondo, Robert Bingham, Kenneth Carslaw, Joachim Curtius, André David, Bent Fastrup, Stéphanie Gagné, F. Hahn, R. Giles Harrison, Barry Kellett, Jasper Kirkby, Markku Kulmala, Lauri Laakso, Ari Laaksonen, Egil Lillestol, Michael Lockwood, Jyrki Mäkelä, Vladimir Makhmutov, Nigel D. Marsh, Tuomo Nieminen, Antti Onnela, E. Pedersen, Jens Olaf Pepke Pedersen, Josef Polny, Ulrike Reichl, John H. Seinfeld, Mikko Sipilä, Yuri Stozhkov, Frank Stratmann, Henrik Svensmark, J. Svensmark, Rob Veenhof, Bart Verheggen, Yrjö Viisanen, Paul E. Wagner, Günther Wehrle, Ernest Weingartner, Heike Wex, Mats Wilhelmsson, Paul M. Winkler
URN:urn:nbn:de:hebis:30-83685
DOI:http://dx.doi.org/10.5194/acp-10-1635-2010
ISSN:1680-7316
ISSN:1680-7324
Parent Title (English):Atmospheric chemistry and physics
Publisher:European Geosciences Union
Place of publication:Katlenburg-Lindau
Document Type:Article
Language:English
Date of Publication (online):2010/02/15
Date of first Publication:2010/02/15
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
Release Date:2010/10/26
Volume:9
Pagenumber:36
First Page:18235
Last Page:18270
Note:
© Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License.
HeBIS PPN:229784941
Institutes:Extern
Dewey Decimal Classification:550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 3.0

$Rev: 11761 $