Low-frequency variability of the Antarctic Circumpolar Wave

This study evaluates the Antarctic Circumpolar Wave (ACW) variability in the Southern Ocean using a 27-year series of sea surface temperature (SST) and sea level pressure (SLP). From a cross-covariance analysis we find that the strongest covariation between the extratropical wavenumber-2 in SST and in SLP is during the austral summer in the South Pacific Ocean. Examination of the time series reveals two timescales of variability. A wavenumber-2 structure in SST and SLP anomalies correlates well at interannual (IA) timescales, when ENSO-driven teleconnections seem to energize the ACW. Moreover, in the 1973-1999 epoch, the ACW has been modulated by interdecadal (ID) variability possibly related to the Southern Oscillation.