1. Ministry of Education Key Laboratory of West China’s Environmental System, Lanzhou Univ., Lanzhou 730000, China; College of Resource and Environmental Science, Lanzhou Univ., Lanzhou 730000, China; and Institution of Urban Planning and Design, Lanzhou Univ., Lanzhou 730000, China.
2. Ministry of Education Key Laboratory of West China’s Environmental System, Lanzhou Univ., Lanzhou 730000, China; College of Resource and Environmental Science, Lanzhou Univ., Lanzhou 730000, China; Institution of Urban Planning and Design, Lanzhou Univ., Lanzhou 730000, China; and Bartlett School of Planning, Univ. College London, London WC1H 0QB, U.K. (corresponding author).
3. College of Resource and Environmental Science, Lanzhou Univ., Lanzhou 730000, China; and, Institution of Urban Planning and Design, Lanzhou Univ., Lanzhou 730000, China.