1. School of Land Science and Techniques, China University of Geosciences, Beijing, China
2. Faculty of Geographical Science, Beijing Normal University, Beijing, China
3. Department of Earth and Environment, Boston University, Boston, MA, USA
4. NASA Ames Research Center, Moffett Field, CA, USA
5. College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China
6. Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland