1. Departamento Física de la Tierra y Astrofísica Universidad Complutense de Madrid Madrid Spain
2. Research Applications Laboratory National Center for Atmospheric Research Boulder CO USA
3. Meteorology and Air Quality Group Wageningen University Wageningen Netherlands
4. Departamento de Física Universitat de les Illes Balears Palma Spain
5. Laboratoire d'Aérologie, CNRS, Université de Toulouse, UPS Toulouse France
6. Centre National d'Études Spatiales (CNES) Toulouse France