北半球环流异常持续性随运动尺度的分布

THE PERSISTENCE DISTRIBUTION OF GENERAL CIRCULATION ANOMALY IN NORTHERN HEMISPHERE WITH KINEMATIC SCALE

本文利用1965年3月—1977年12月500 hPa逐日位势高度距平场资料,用谐波分析方法和经验正交函数分解方法把大气运动按水平尺度谱展开,分析了北半球大气环流异常随水平运动尺度的分布规律。谐波分析的计算结果表明:超长波的持续性要好于长波的持续性;在低纬度地区,各波的持续性当后延时间较短时要小于高纬度地区的持续性,但随后延时间的增加高纬度地区的持续性衰减迅速,结果是当后延时间较长时高纬度地区的持续性小于低纬度地区。经验正交函数分解的分析结果则表明:第一特征向量对应的持续性及其对整体持续性的贡献最大,随特征值的衰减,其持续性及贡献呈减小趋势。

In this paper the persistences of daily 500 hPa geopotential height anomaly on different scales during the period of from March of 1965 to December of 1977 are studied with harmonic and EOF analyses.The harmonic analysis shows that: the persistence on ultra-long wave scale is better than that on long wave scale; in the low latitude area, the persistence on all scales are worse than those in high latitudes when lag time is short. But the case is reversed when the lag time becomes longer because of the rapid decreasing of persistence in high latitudes. The results of EOFs show that the persistence of the first eigenvector and its contribution to total persistence are the largest, and with the decreasing of the eigenvalue, the persistence and its contribution to total persistence become small.