Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China;
Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China;
Cold and Arid Regions Environmental and Engineering Research Institute, CAS, Lanzhou 730000, China;
Institute of Resource and Environmental Sciences, Beijing Normal University,Beijing 100875, China;
China; the index of aridity; dry and wet climate boundary; fluctuation;