1. Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
2. State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
3. School of Earth and Environmental Sciences, The University of Queensland, Brisbane 4067, Australia.
4. State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
5. Department of Geography, Environment and Spatial Sciences, Michigan State University, East Lansing, MI 48824, USA.