基金Supported by Special Fund of Public Industry from Ministry of Science and Technology (GYHY200806021)National Natural Science Foundation Emphases Item of China (40830957)+2 种基金Project of Researches on Drought Meteorological Science (IAM200811)Special Fund for Climatic Change in China Meteorological Bureau (CCSS-09-14)Technology-aid Project in Gansu (090NKCA118)~~