东亚季风垂直环流的低频振荡及其机制

LOW FREQUENCY OSCILLATION OF THE EAST ASIAN MONSOON VERTICAL CIRCULATION AND ITS MECHANISM

用1984年6月1日至9月30日欧洲中心中期数值预报资料(ECMWF)重点分析了东亚夏季风垂直环流的低频振荡及其与季风活动的关系,指出了垂直经向环流和赤道纬向环流都存在明显的局地低频振荡,初步讨论了东亚夏季风经圈环流的低频振荡起源于南半球30°S处对流层中高层垂直运动的低频振荡,通过经圈环流的低频振荡使南北半球的低频振荡相互联系起来。最后分析了热带季风低频振荡与梅雨活动的可能联系。

The low frequency oscillation(LFO)of the East Asian summer monsoon vertical circulation and its relationship with monsoom activities are analyzed in this paper using the ECMWF data from June 1 to September30,1984,indicating that significant local LFO exists in both the vertical meridional circulation and equatorial zonal circulation and that the LFO of the East Asian monsoon meridional circulation originated from the LFO vertically moving in the middle and upper troposphere at 30°S. The LFO in the southern and northern hemispheres are linked by the LFO of the meridional circulation. Besides,the possible relationship between the LFO of the tropical monsoon and Meiyu occurrence is discussed.