摘要
本文以EOF方法为基础对北半球50hPa高度月平均距平场进行了分析,指出北半球50hPa场存在着几种定常的环流型,且它的距平场的 EOF 展开精度具有相当好的稳定性。另外,北半球50hPa高度月平均距平场高、中纬之间存在着远远超过 a=0.001信度检验的“跷跷板”式振荡。功率谱分析发现,北半球50hPa 环流场有着显著的准2—3年及准4个月振荡周期,赤道平流层 QBO 现象在高度场上也有清楚的反映。通过与对流层的 EOF 分析比较得到,500hPa 与50hPa 第一、第二特征向量场有相似的空间分布,但对于 EOF 展开无论是从拟合精度的稳定性还是收敛性看,平流层都远远优于对流层。
In this paper,we analysed the 50hPa potential height anomaly field in the Northern Hemisphere using the EOF method.It is indicated that(1)there are several stationary circulation pat-terns in 50hPa field of the Northern Hemisphere,and the stable fitting precision of EOF,(2)thereis a obvious“see-saw”phenomenon between high latitude and middle latitude in the 50hPa poten-tial height anomaly field of the Northern Hemisphere,(3)the quasi-biennial to quasi-triennial os-cillation and quasi-four month oscillation of 50hPa circulation field in the Northern Hemisphereexist obviously,and the QBO phenomenon of equatorial stratosphere is also verified,and(4)ascompared between the 500 hPa and 50 hPa field,the first and second characteristic vectors of po-tential height anomaly field have the similar spatial distribution,but EOF expansion in the stratosphere whether the stability of fitting precision or the convergence is better than that in the troposphere.
出处
《应用气象学报》
CSCD
北大核心
1992年第2期173-180,共8页
Journal of Applied Meteorological Science
