1 Information Center for Global Change Studies, Lanzhou Information Center, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: jsqu@lzb.ac.cn.
2 Information Center for Global Change Studies, Lanzhou Information Center, Chinese Academy of Sciences, Lanzhou 730000, China.
3 Information Center for Global Change Studies, Lanzhou Information Center, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
4 Information Center for Global Change Studies, Lanzhou Information Center, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China; University of Southern Queensland, Toowoomba, Queensland 4350, Australia.