We examine the time evolution over an 11 yr time series of the dominant modes of variability in sea level anomalies (SLA) from TOPEX/Poseidon and ERS-1/2 in the Southern Ocean (35--60¿S). We use Hayashi's classical space-time spectral analysis and a newly developed method combining a Gabor analysis with Hayashi's method. Zonal wavenumbers 3 and 2 emerge unambiguously with null corresponding meridional wavenumber meaning that both associated modes have no meridional propagation. Their power spectrum density (PSD) is maximum within 50--55¿S. The 3/0 mode displays a clear westward propagation associated with a 1.04 yr period. The 2/0 pair is characterized by a ~4.4 yr period and exhibits a clear eastward propagation with a maximal PSD just after the 1998 El Ni¿o peak. Zonal wavenumber-2 mode is then probably part of the Antarctic Circumpolar Wave.