1. Centre National de recherches Météorologiques (CNRM), UMR3589; Météo-France and CNRS Toulouse France
2. Institute of Atmospheric Sciences and Climate (ISAC); National Research Council of Italy (CNR); Bologna Italy
3. Danish Meteorological Institute; Copenhagen Denmark
4. CETEMPS - Department of Physics; University of L'Aquila; Italy
5. LATMOS/IPSL, UPMC Univ. Paris 06 Sorbonne Universités, UVSQ, CNRS; Paris France
6. Universitat de les Illes Balears; Palma Spain
7. Institute of Meteorology and Climate Research; Karlsruhe Institute of Technology (KIT); Germany
8. Laboratoire d'Aérologie; Université de Toulouse, CNRS, UPS; France
9. Institute for Atmospheric and Climate Science; ETH; Zurich Switzerland