1. Alfred Wegener Institut für Meeresund Polarforschung, Am Telegrafenberg A43, Postfach 600149, 14401 Potsdam, Germany;
2. Alfred Wegener Institut für Meeres- und Polarforschung, Postfach 120161, 27515 Bremerhaven, Germany;
3. Institute for Applied Environmental Research, Air-pollution Laboratory, Stockholm University, 106 91 Stockholm, Sweden;
4. National Institute of Polar Research, 9-10 Kaga 1 chome, Itabashi-ku, Tokyo 173-8515, Japan;
5. Hokkaido University, Graduate School of Engineering, N13W8 Sapporo 060-8628, Japan;
6. Norwegian Institute of Air Research, The Polar Environment Centre, N-9296 Tromsø, Norway