1. Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
2. Institute for Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria
3. Department of Geography, University of Zurich, Zurich, Switzerland
4. Mathematics Institute for Analysis and Applications, EPF Lausanne, Lausanne, Switzerland
5. Institute of Mathematics and Modeling, University of Montpellier II, Montpellier, France
6. Royal Meteorological Institute of Belgium, Brussels, Belgium
7. German Meteorological Service (DWD), Meteorological Observatory Hohenpeissenberg, Germany
8. Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland
9. Czech Hydrometeorological Institute, Hradec Kralove, Czech Republic