1. Ph.D. Student, Cold and Arid Regions Environmental and Engineering Research Institute, CAS, No. 260 Donggang West Rd., Lanzhou 730000, China (corresponding author). E-mail: caipinglz@163.com
2. Professor, Cold and Arid Regions Environmental and Engineering Research Institute, CAS, No. 260 Donggang West Rd., Lanzhou 730000, China. E-mail: dyj@lzb.ac.cn
3. Professor, Cold and Arid Regions Environmental and Engineering Research Institute, CAS, No. 260 Donggang West Rd., Lanzhou 730000, China. E-mail: liusy@lzb.ac.cn