1. British Antarctic Survey; Cambridge UK
2. Department of Physics; University of Otago; Dunedin New Zealand
3. Department of Meteorology (MISU); Stockholm University; Stockholm Sweden
4. Formerly at Finnish Meteorological Institute; Helsinki Finland
5. Space and Earth Observation Centre; Finnish Meteorological Institute; Helsinki Finland
6. Atmospheric Chemistry Division; National Center for Atmospheric Research; Boulder CO USA
7. School of Chemistry; University of Leeds; Leeds UK
8. National Centre for Atmospheric Science, School of Earth and Environment; University of Leeds; Leeds UK