1. Institute of Coastal Research; Helmholtz-Zentrum Geesthacht; Geesthacht Germany
2. Now at Department of Atmospheric and Oceanic Sciences; University of California Los Angeles; California USA
3. Also at Jet Propulsion Laboratory; California Institute of Technology; Pasadena, California USA
4. Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research; University of Bern; Bern Switzerland
5. Now at Department of Physics; University of Murcia; Spain