1. School of Geodesy and Geomatics and Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University, Wuhan, China,
2. Geophysical Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
3. Institute of Geosciences, University of Potsdam, Potsdam, Germany
4. Institute of Bio and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany