华南前汛期降水异常与水汽输送的关系

Relation between Pre-flood Season Precipitation Anomalies in South China and Water Vapor Transportation

采用1958—2000年华南57站前汛期日降水资料和NCEP/NCAR逐日水汽输送再分析资料,分析了华南前汛期降水异常与水汽输送的关系,并对旱、涝年进行了比较分析。结果表明:华南地区经向水汽输送的异常变化将导致该地区的异常旱涝,而纬向水汽输送的异常变化只导致该地区出现小范围的降水异常。旱年和涝年的异常水汽输送不是简单的反位相关系。来自印度洋和西太平洋的水汽对华南地区前汛期的降水异常没有明显的作用,南海(主要是其北部)才是华南降水异常的关键区。

Relation between pre-flood season precipitation anomalies in South China and water vapor transport is analyzed by using the daily precipitation data of 57 stations in South China and the NCEP/NCAR reanalysis daily data for water vapor transport from 1958 to 2000,and the differences between drought and flood years are studied.Results show that anomalous meridional water vapor transport in South China will cause anomalous droughts or floods in South China,but anomalous zonal water vapor transport only causes the local precipitation anomaly;the anomalous water vapor transport in drought and flood years is not a simple out-of-phase relation;and the water vapor coming from the Indian Ocean and the West Pacific do not obviously affect the pre-flood season precipitation anomaly in South China,in fact,the South China Sea(particularly its north) is the key area of water vapor source for the precipitation anomaly of the South China.