1. Department of Space and Climate Physics, Mullard Space Science Laboratory; University College London; London UK
2. British Antarctic Survey; Cambridge UK
3. Applied Physics Laboratory; Johns Hopkins University; Baltimore MD USA
4. Los Alamos National Laboratory; Los Alamos NM USA
5. Institute for the Study of Earth, Oceans, and Space; University of New Hampshire; Durham NH USA
6. Department of Physics and Astronomy; University of Southampton; Southampton UK