Key Laboratory of Western China's Environmental Systems(Ministry of Education), Lanzhou University, Lanzhou 730000, China;
Key Laboratory of Western China's Environmental Systems(Ministry of Education), Lanzhou University, Lanzhou 730000, China;
Key Laboratory of Western China's Environmental Systems(Ministry of Education), Lanzhou University, Lanzhou 730000, China;
Key Laboratory of Western China's Environmental Systems(Ministry of Education), Lanzhou University, Lanzhou 730000, China;
Key Laboratory of Western China's Environmental Systems(Ministry of Education), Lanzhou University, Lanzhou 730000, China;
Key Laboratory of Western China's Environmental Systems(Ministry of Education), Lanzhou University, Lanzhou 730000, China;
Geography Department, Royal Holloway, University of London, Surrey TW20 0EX, UK;