1. Leibniz Institute for Tropospheric Research, Permoserstraße 15, 04318 Leipzig, Germany;
2. Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Becherweg 21, 55099 Mainz, Germany;
3. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309, USA
4. Meteorological Institute, University of Munich, Theresienstraße 37, 80333 München, Germany;
5. Remote Sensing Technology Institute IMF, German Aerospace Center (DLR), Münchner Straße 20, 82234 Oberpfaffenhofen, Germany;
6. Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany;
7. Jet Propulsion Laboratory (JPL), 4800 Oak Grove Dr., Pasadena, CA 91109, USA;