1 Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: jhchen@lzu.edu.cn.
2 Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
3 Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China; Key Laboratory of Alpine Ecology and Biodiversity (LAEB), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth System Sciences, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: jbliu@itpcas.ac.cn.
4 College of Resources and Environmental Sciences, Hunan Normal University, Changsha 410081, China.
5 Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China; Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven 27570, Germany.