秋季中低纬低频振荡传播与长江中下游的连晴、连阴雨

LOWMID LATITUTE LFO PROPAGATION FEATURES RELATED TO PARTICULAR AUTUMN WEATHER TYPES IN CHANGJIANG BASINS

对１９８３年～１９８５年９月～１１月份８５０ｈｐａ的经纬向风场进行了１５ｄ～２５ｄ的带通滤波分析。结果表明，１１０°Ｅ经向风低频振荡波存在阶段性地从南半球（北半球）越过赤道向北（南）传播，低频越赤道气流存在阶段性地明显向东、向西传播，它们在５天平均低频风场中表现为低频气旋、反气旋环流的周期性振荡变化，并都与长江中下游地区的连晴、连阴雨天气的时间分布相联系。

15～25 day bandpass filtering was undertaken of 1983～1985 September-November 850 hPa zonal wind. Results suggest that 110 °E meridional wind LFO (lowfrequency oscillation) wave exhibits north (southward) propagation from the Southern (Northern) Hemisphere across the equator in a phasic manner and lowfrequency crossequatorial flow displays salient propagation east and westward, showing periodic oscillation as cyclonic and anticyclonic circulation in the pentad mean wind. They are associated with the timevarying distribution of long spells of fine and overcast/rainy weather in autumn over the Changjiang basins in east and central China.