Teleconnection patterns in the Southern Hemisphere
Contemporaneous correlations between geopotential heights on a given pressure surface at widely separated points on Earth, commonly referred to as teleconnections, are calculated from monthly mean sea level pressure and 500 mb geopotential height analyses for the Southern Hemisphere for five-month winter and summer seasons. During summer (November-March), anomalies over the three continents occur out of phase with anomalies over the subtropical oceans and in a wavenumber 3 pattern over the Southern Ocean near 55 deg S. The subtropical part of the pattern appears largely associated with the interannual variation of the seasonal cycle and annual mean. In winter (May-September) 500 mb geopotential heights over Africa exhibit positive correlations with heights over South America and the central South Pacific near New Zealand and negative correlations with height over the Southern Ocean. A striking wavenumber three pattern is apparent which shows the correlation of 500 mb geopotential height anomalies with 500 mb anomalies at 50 deg S, 95 deg E during winter. The strong positive correlations between 50 deg S, 95 E and 58 deg S, 150 deg W and 38 deg S, 15 deg W contrast with negative correlations over Antarctica and in low latitudes. Time variations in a similar pattern in sea level pressure are in phase with variations in the 500 mb pattern, suggesting an equivalent barotropic structure.