月平均位势高度场异常持续性初步分析

Preliminary Analysis of Anomalous Persistence of Mean Monthly Geopoential Height Fields

使用 NCEP/ NCAR的 50 0 h Pa月平均位势高度场球函数展开系数资料 ,分析了北、南半球 1、7月具有较大年际异常方差贡献的 5种低阶球函数 (全波数 n=0～ 4)分量振幅异常的持续性 ,以及它们与热带太平洋海表温度年际异常的关系。结果表明 :振幅异常的持续性随 n增大迅速减小 ,明显的持续性只存在于少数低 n值超长波分量 ;均匀球函数分量振幅异常的持续性显著 ,且存在季节、半球际差异 ;北、南半球均匀球函数分量 (n=0 )振幅异常呈准同步变化 ,它们与热带太平洋 SSTA在 EN-SO尺度上准同步 ;南半球 n=2的带型球函数分量振幅异常也具有较强的持续性 ,且其变化与热带太平洋

The persistence of amplitude anomaly of five low order spherical functions of total wave numbers n=0～4 with larger interannual anomaly variance contributions in Northern and Southern Hemisphere in January and July and its relations to tropical Pacific ocean surface temperature year-to-year anomaly(SSTA) are examined on the basis of spherical function coefficients of NCEP/NCAR 500hPa mean monthly geopotential height fields. The result shows that: 1)persistence of amplitude anomaly decreases quickly with the increase of the function n,and apparent persistence exists only in a few extra-long wave components with small n values; 2)amplitude anomaly of even spherical function(n=0) components is of noticeable persistence with seasonal and hemispheric differences;3)the amplitude anomalies of even spherical function components(n=0) of Northern and Southern Hemisphere are quasi-synchronism and so are they with tropical Pacific SSTA in ENSO scales; 4)amplitude anomaly of Southern band spherical function components (n=2) is also of appreciable persistence, and is quasi-synchronism with tropical Pacific SSTA in interdecadal scales.