Periodicities and Latitudinal Interactions of Mean Zonal Flow on the 5-day Mean 500-mb Surface

Abstract

The nature of variation of mean zonal wind for the 500-mb surface was investigated in two winters. The well-defined southerly trends of ΔU were frequently observed, and consequently they also influenced the cross correlation of ΔU between a particular latitude and the others. The periodicity of about 25-day was found in middle latitudes and it coincided with the mean period which was calculated from a dynamical theory of mean zonal wind.