1. Electrical Engineering Department; Technological University of Catalonia; Terrassa Spain
2. Meteorological Service of Catalonia; Barcelona Spain
3. Department of Signal Theory and Communications; Universidad Rey Juan Carlos; Madrid Spain
4. Department of Astronomy and Astrophysics; University of Valencia; Burjassot Spain
5. Laboratoire d'Aérologie, UMR 5560; UPS, CNRS, OMP; Toulouse France