国家公益性行业气象科研专项GYHY201306035,GYHY201306036;国家"十二五"科技支撑计划项目2011BAD32B01资助.This study was supported by Special Fund for Meteorology-scientific Research in the Public InterestGYHY201306035,GYHY201306036;Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period2011BAD32B01