1. School of Electronic and Information Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu, China
2. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu, China
3. Gansu Data Engineering and Technology Research Center for Resources and Environment, Lanzhou, Gansu, China
4. College of Information Science and Technology, Gansu Agricultural University, Lanzhou, Gansu, China