利用卫星遥感反演的降水资料及中国740个测站逐日降水资料,根据定义的旱涝指数,划分了1957-2002年期间的华南旱涝年份。利用NCEP/NCAR逐日再分析资料,分别讨论华南前汛期4~6月、4月及6月的水汽输送的气候特征。在此基础上,进一步研究了4~6月、4月及6月水汽输送及其源地在华南前汛期涝年和旱年的不同特征。结果表明:影响华南的水汽输送环流在南海夏季风建立前后具有明显不同的气候特征,华南前汛期(4~6月)降水应分为南海夏季风爆发前4月份至夏季风爆发与南海夏季风爆发至6月两个时段。来源于西太平洋的水汽输送变化和来自中国北方的水汽输送变化对华南降水异常有重要作用,而阿拉伯海-孟加拉湾地区的水汽输送变化对华南的降水异常影响不大。

Using the CMAP,daily observatory rainfall data and NCEP/NCAR reanalysis data,the climatic features of moisture transport and their differences between pre-summer flood season of flood and drought years over South China(SC) are discussed.Results show that there are obvious different climate characteristics for the moisture transport circulation of South China influenced before and after South China summer monsoon(SCSM) onset,and so the precipitation of SC in pre-summer flood season should be divided into two stages: From April to SCSSM onset and from SCSSM onset to June.The variations of moisture transport from the West Pacific and North China have important effects on flood or drought of SC,but that from Arabian Sea-Bay of Bangle exerts little influence on abnormal rainfall over SC.