ANTARCTIC SEA-ICE OSCILLATION AND ITS RELATIONSHIP WITH ENSO

Antarctic Sea-ice oscillation and its relationship with indices of the atmospheric circulation of the Southern Hemisphere are examined by using 30 year Antarctic sea-ice concentration and NCEP data from January 1968 to December 1997 based on the EOF and SVD methods. A out-phase relationship is found between Ross Sea and Bellingshausen Sea, whose characteristics of the variation is defined as Antarctic Sea-ice Oscillation. Its index (ASOI) has a high correlation with SOI and Nino 3 Index when it is two months ahead of them. The high index and low index composite figures reveal the completely reverse patterns of SAT, SLP, and wind circulation in the Southern Ocean for the two extreme states. The sea-ice anomalies of the two key regions accompany with the opposite wind circulation which may influence the currents of the Southern Pacific ocean and the development of E1 Nino/La Nina events. This evidence indicates a possible ENSO signal between Ross sea and Bellingshausen sea.