1. Measurement and Data Department, Federal Office of Meteorology and Climatology MeteoSwiss, Payerne, Switzerland
2. Analysis and Forecast Department, Federal Office of Meteorology and Climatology MeteoSwiss, Zurich, Switzerland
3. Institute of Solar Research, German Aerospace Centre, Tabernas, Spain
4. Renewable Energy Division, Centre for Energy, Environment and Technological Research CIEMAT, Madrid, Spain