1. China University of Geosciences (Beijing), School of Geophysics and Information Technology, Beijing, China and China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, Beijing, China.
2. China University of Geosciences (Beijing), School of Geophysics and Information Technology, Beijing, China and China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, Beijing, China. (corresponding author)
3. China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, Beijing, China.