1. Alfred Wegener Institute for Polar and Marine Research Potsdam Germany
2. NorthWest Research Associates Socorro NM USA
3. New Mexico Institute of Mining and Technology Socorro NM USA
4. Air Quality Research Division Environment and Climate Change Canada Downsview Ontario Canada
5. Danish Meteorological Institute Copenhagen Denmark
6. Space and Earth Observation Centre Finnish Meteorological Institute Sodankylä Finland
7. Lerwick Observatory UK Met Office Shetland Islands UK