Martin Müller¹, Thomas Browning², Nolwenn Lemaitre³, Eric P Achterberg² and Derek Vance¹, (1)ETH Swiss Federal Institute of Technology Zurich, Department of Earth and Planetary Sciences, Zurich, Switzerland, (2)GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany, (3)Laboratory of Space Geophysical and Oceanographic Studies (LEGOS), Toulouse, France