半球月平均位势高度场的若干环流指数及其变化特征

Some Circulation Indices and Their Variation Character of Hemispherical Monthly Mean Geopotential Height Fields

给出了表征半球月平均位势高度场性质的若干环流指数 :气候场强度 Ic、气候异常场平均强度 Ia、气候场不稳定度 Ius。用 NCEP/ NCAR4 0 a再分析月平均位势高度场资料作了计算和分析 ,结果表明 ,这些环流指数存在清晰的时空结构和北、南半球差异 ,它们概括地给出了地球大气位势高度场气候及其异常的基本特点。

To describe the nature of hemispherical monthly mean geopotential height fields,several circulation indices,such as intensity of climate fields I c,intensity of climate anomaly fields I a,instability of climate fields I us ,are defined.Calculation and analysis are performed based on the monthly mean geopotential height fields from NCEP/NCAR 40a reanalysis datsets.Results suggest that the indices exhibit evident spatial-temporal structure and significant difference between Northern and Southern Hemisphere.The basic characterics of the climatology and anomaly of atmospheric geopotential height field are generally presented by the indices proposed.