1. Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, P. R. China
2. Department of Geography, State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong SAR 999077, P. R. China
3. Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
4. School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
5. National Centre for Atmospheric Science, University of Leeds, Leeds LS2 9JT, United Kingdom
6. School of Electronic and Information Engineering, Lanzhou Jiaotong University, Lanzhou 730000, P. R. China