Abstract: The spectra of kinetic energy, transfer of angular momentum and energy transformation between eddy and tonal kinetic energy are analysed for a period of large-scale,synoptic variation. It is, shown that the wave of wave number five plays an important role in the change of circulation. During the breakdown of tonal circulation the angular-momentum transfer is northward6, and this northward transfer is accomplished‘ mostly by the wave of wave number 5. During the formation of tonal circulation the transfer of angular momentum is southward6 and this is also mostly accomplished by the wave of. wave number 5.