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Göran Frank

Director of graduate studies

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Overview of the Po valley fog experiment 1994 (CHEMDROP)


  • Sandro Fuzzi
  • Paolo Laj
  • Loretta Ricci
  • Giordano Orsi
  • Jost Heintzenberg
  • Manfred Wendisch
  • Brett Yuskiewicz
  • Stephan Mertes
  • Douglas Orsini
  • Marina Schwanz
  • Alfred Wiedensohler
  • Frank Stratmann
  • Olle H. Berg
  • Erik Swietlicki
  • Göran Frank
  • Bengt G. Martinsson
  • Armin Günther
  • Jens Peter Dierssen
  • Dieter Schell
  • Wolfgang Jaeschke
  • Axel Berner
  • Ulrike Dusek
  • Zsuzsanna Galambos
  • Christian Kruisz
  • Nigatu S. Mesfin
  • Wolfram Wobrock
  • Beate Arends
  • H. Ten Brink

Summary, in English

The paper presents an outline of the CHEMDROP field experiment, carried out in November 1994 at the field station of S. Pietro Capofiume in the Po Valley, Italy. The main objective of the project was to address the issue of the size-dependent chemical composition of fog droplets, by experimentally investigating the following processes, which are expected to affect (or be affected by) the chemical composition of fog droplets as a function of size: a) the connection of the size-dependent chemical composition of CCN to the size-dependent composition of fog droplets; b) the gas/liquid partitioning of the gaseous species NH3, SO2, HCHO, HNO3 in fog; c) the Fe(II)/Fe(III) redox cycle in fog water. Some general results and overall conclusions of the experiment are reported in this paper, while more specific scientific questions are discussed in other companion papers in this issue. CHEMDROP results show that several processes concur in determining the size-dependence of fog droplets chemical composition: nucleation scavenging of pre-existing CCN, fog dynamical evolution and gas/liquid exchange between interstitial air and fog droplets. Chemical transformations in the liquid phase can cause further changes in the chemical composition of the droplets. Only by taking into account the combination of all these processes, is it possible to explain the inhomogeneities in fog droplet chemical composition.


  • Nuclear physics

Publishing year







Contributions to Atmospheric Physics





Document type

Journal article review


Deutsche Meteorologische Gesellschaft / Friedr. Vieweg & Sohn Verlagsgesellschaft mbh


  • Meteorology and Atmospheric Sciences




  • ISSN: 0005-8173