Hugo Plombat¹, Brian K Arbic², Dale H Boggs³, Dimitris Menemenlis⁴, Lana Opel⁵, Richard Ray⁶, Michael Schindelegger⁵ and James G Williams³, (1)University of Michigan, Earth and Environmental Sciences, Ann Arbor, United States, (2)University of Michigan, Earth and Environmental Sciences, Ann Arbor, MI, United States, (3)Jet Propulsion Laboratory, Pasadena, United States, (4)San Jose State University, San Jose, United States, (5)University of Bonn, Institute of Geodesy and Geoinformation, Bonn, Germany, (6)NASA Goddard Space Flight Center, Geodesy & Geophysics Lab, Greenbelt, United States