Teleconnection between the central tropical Pacific and the Antarctic stratosphere: spatial patterns and time lags

Abstract

Coupling between the central tropical Pacific (CTP) sea surface temperature (SST) variability and the Antarctic stratosphere known from previous studies is analysed using a lagged correlation method. Monthly mean SST, stratospheric temperatures and zonal winds from the NCEP–NCAR reanalysis and total ozone from the Merged Ozone Data Set over the 1979–2011 period are used. Indices for interannual variability were created and sequential lagged correlations were used to determine the spatial patterns and time lags of the strongest teleconnection. It has been revealed that interannual SST variations in a westward-oriented V-shaped pattern in the CTP region (160–220°E, 30°N–20°S) are associated with statistically significant positive signals in zonally asymmetric region of the Antarctic stratosphere temperature field. Stratospheric pathway dominates in the poleward and downward propagation of the CTP related anomaly in the Southern Hemisphere zonal wind variability. Abrupt modification of the teleconnection patterns in October is accompanied by occurrence of the intense meridional wave train in the lower stratosphere and troposphere. The strongest lagged correlations between the CTP SST index in June and the Southern Hemisphere atmosphere variables in October (r = ±0.7) could be related to the corresponding seasonal peaks in the stationary planetary wave activity. Possible causes of the V-pattern formation and the lagged teleconnection mechanisms are briefly discussed.