7—9月500百帕高度场30—50天振荡的遥相关结构及其演变特征

TELECONNECTION AND TIME-VARIATION OF 30—50 DAY OSCILLATION OF THE 500hPa HEIGHT FIELD DURING JULY-SEPTEMBER

利用1982、1983年7—9月的欧洲中期天气预报中心(ECMWF)网格点资料,分析了北半球中高纬度以及热带地区500百帕高度场的30—50天周期振荡的遥相关结构及其演变特征。发现30—50天周期振荡的分布,在热带与对流活动中心相对应,在中高纬地区与主要的气压活动中心相配合。振荡的相关中心分布于15—70°N之间,并成大弧状排列,具有波列的结构特征,其路径具有显著的年际变化,其弧状排列的振荡中心具有纬向移动,移动方向与高度场振荡位相的纬向移动相一致,高度场振荡的纬向移动和波列的能量频散密切相关。

By using July-September grid data of 1982 and 1983 from theECMWF, the teleconnection structure and time-variation of 30-50dayoscillation of the 500 hPa height field in the northern extratropicsand tropics are examined. It is found that the distribution of 30-50 dayoscillation is correlated with the centers of convective activities inthe tropics and with the major centers of the pressure system in theextratropics. The correlation centers of the oscillation are distributedbetween 15-70°N and arranged in the form of a big are with structuralcharacteristics of a wavetrain and prominent annual variability on theirpropagation track. The zonal propagation of the oscillation centers corre-sponds to that of the oscillation phase of the height field, which is closely correlated with the energy dispersion of the wavetrain.