[1]State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China;
[2]School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;
[3]Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA;