1. Jet Propulsion Laboratory; California Institute of Technology; Pasadena California USA
2. Department of Earth, Planetary, and Space Sciences; University of California; Los Angeles California USA
3. Helmholtz Centre Potsdam; GFZ German Research Centre for Geosciences; Potsdam Germany
4. Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
5. British Atlantic Survey; Cambridge UK