1. School of Public Policy and Management, China University of Mining and Technology, Xuzhou 221116, China
2. Research Center for Transition Development and Rural Revitalization of Resource-Based Cities in China, China University of Mining and Technology, Xuzhou 221116, China
3. Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing 100084, China
4. Institute of Loess Plateau, Shanxi University, Taiyuan 030006, China