1. School of Earth and Space Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, Anhui, China, zhuwei07@mail.ustc.edu.cn
2. State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, 340 Xudong Street, Wuhan 430077, Hubei, China, sdni@whigg.ac.cn, zengxf@whigg.ac.cn
3. AECOM Technology Corporation, One California Plaza, 300 S Grand Avenue, Los Angeles, California 90017, paul.somerville@aecom.com