1. Department of Physics Lancaster University Lancaster UK
2. Now at GFZ German Research Centre for Geosciences Potsdam Germany
3. South African National Space Agency Hermanus South Africa
4. University of Western Cape Bellville South Africa
5. National Institute of Polar Research Tachikawa Japan
6. Department of Polar Science, School of Multidisciplinary Sciences SOKENDAI (Graduate University for Advanced Studies) Tachikawa Japan