Institute of Atmospheric Physics, Bocni II, 14131 Prague, Czech Republic

Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA

Indian Institute of Tropical Meteorology, Pune-411 008, India

Leibnitz-Institute of Atmospheric Physics, Schloss-Street 6, 18225, Kühlungsborn, Germany

Naval Research Laboratory, Washington, D.C. 20375, USA

Institute for Meteorology, University of Leipzig, Stephanstr. 3, 04103 Leipzig, Germany

British Antarctic Survey, Cambridge, CB3 0ET, UK

Naval Research Laboratory, Washington, D.C. 20375, USA

Institute for Experimental Meteorology, Lenin Str. 82, Obninsk 249038, Russia

Sodankylä Geophysical Observatory, Tähteläntie 62, 99600 Sodankylä, Finland