1. Finnish Meteorological Institute, Helsinki, Finland
2. Finnish Meteorological Institute, and Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland
3. Deutscher Wetterdienst, Offenbach, Germany
4. European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
5. Group on Earth Observations Secretariat, Geneva, Switzerland
6. University of Twente, Enschede, Netherlands