1. Institute of Environmental Physics; University of Bremen; Bremen Germany
2. CNRS/LATMOS/UPMC; Paris France
3. NASA Jet Propulsion Laboratory; California Institute of Technology; Pasadena California USA
4. IMK, Karlsruhe Institute of Technology; Karlsruhe Germany
5. Physikalisch-Technische Bundesanstalt; Braunschweig Germany
6. Department of Atmospheric Sciences; University of Arizona; Tucson Arizona USA
7. Rossby Centre; Swedish Meteorological and Hydrological Institute; Norrköping Sweden