1. Physical Sciences Division; British Antarctic Survey, NERC; Cambridge UK
2. British Antarctic Survey, NERC; Cambridge, England UK
3. Finnish Meteorological Institute; Helsinki Finland
4. Department of Physics; University of Otago; Dunedin New Zealand
5. NASA Langley Research Center; Hampton Virginia USA
6. Department of Atmospheric, Oceanic and Space Sciences, College of Engineering; University of Michigan; Ann Arbor Michigan USA