AN ANTARCTIC CIRCUMPOLAR WAVE IN SURFACE PRESSURE, WIND, TEMPERATURE AND SEA-ICE EXTENT

THE Southern Ocean is the only oceanic domain encircling the globe. It contains the strong eastward flow of the Antarctic Circumpolar Curren t, acid is the unifying link for exchanges of water masses at all dept hs between the world's major ocean basins(1). As these exchanges are a n important control on mean global climate, the Southern Ocean is expe cted to play an important role in transmitting climate anomalies aroun d the globe. Interannual variability has been often observed at high s outhern latitudes, and observations of sea-ice extent suggest that suc h features propagate eastwards around the Southern Ocean(2,3). Here we use data from a variety of observational techniques to identify signi ficant interannual variations in the atmospheric pressure at sea level , wind stress, sea surface temperature and sea-ice extent over the Sou thern Ocean. These anomalies propagate eastward with the circumpolar f low, with a period of 4-5 years and taking 8-10 years to encircle the pole. This system of coupled anomalies, which we call the Antarctic Ci rcumpolar Wave, is likely to play an important role in climate regulat ion and dynamics both within and beyond the Southern Ocean.