长江中下游持续性多雨与南北半球大气环流的季节变化

根据10年实测风资料，在分析南、北半球纬向风场和经向风场演变的基础上，发现长江中下游6—7月持续性多雨年的大气环流的季节变化上有异常现象；即在南半球比常年提前1—2个月结束夏季，在北半球比常年推迟1—2个月进入盛夏。这种异常现象表明长江中下游持续性多雨是全球尺度大气环流异常的反映，为持续性多雨的长期预报提供了新的依据。

Seasonal Variation of Atmospheric Circulation and the Rainy Years

Based on the observed wind data during 1971—1980, the seasonal variations of the meridional and zonal wind fields in 140oE section are analysed. It is found that in rainy tears during June-July the summer season in the Southern Hemisphere ends 1—2 months earlier than normal in the middle and lower Yangtze River, while the summer season in the Northern Hemisphere starts 1—2 months later than normal. It shows that the flood in the Mei-yu period seems to be associated with the anomalies of the circulations in the Southern and Northern Hemispheres