Abstract
A time series of daily data from May 1972 through November 1980 has been used to estimate the annual cycle of the large-scale 500-mb geopotential height fields. The resulting Fourier coefficients, describing the smooth annual cycle, have been used to study the annual cycle of the planetary-scale Southern Hemispere seasonally forced waves and the momentum flux caused by these waves. The results are compared with an analogous study for the Northern Hemisphere. The amplitudes of zonal wave numbers 2 and 3 are far less pronounced in the Southern than in the Northern Hemisphere, and so is the momentum flux caused by these waves. In both hemispheres during the winter and polewards of a given latitude the momentum flux due to zonal wave number 2 is directed towards the equator. The flux is stronger and occupies a wider latitudinal zone in the Northern Hemisphere than in the Southern Hemisphere.
