Abstract
We outline the half-yearly oscillations in sea-level pressure gradients and zonal winds on the Southern Hemisphere by means of daily synoptic maps for several years. The pressure oscillation has amplitude peaks near 50° and the Antarctic coast, separated by a minimum along 60° where the phase changes from maxima in the extreme seasons in the south to maxima in the transitional season in the north. The zonal geostrophic wind consequently has a half-yearly wave with equinoctial maxima in the latitudes near 60°, and one with solstitial maxima north of 50°. We describe the interannual variability of the half-yearly oscillations in the pressure gradients and winds, and give examples of the oscillations during FGGE and the IGY. DOI: 10.1111/j.1600-0870.1984.tb00224.x