Variability of the atmospheric circulation in the southern hemisphere during the last glacial maximum

[1] A high-resolution atmospheric climate model has been used to investigate short-term variability of the atmospheric circulation in the Southern Hemisphere during the Last Glacial Maximum (LGM). The model was forced at the lower boundary by sea surface temperatures (SSTs) and sea ice fields from a lower-resolution coupled model simulation of the LGM. Although the semiannual oscillation (SAO) in the control simulation showed a different annual cycle than in the National Centers for Environmental Prediction (NCEP) reanalysis, the LGM SAO was similar to that of today, albeit slightly weaker, with the onset of the second peak delayed by a month. Nearly one third of the interannual variability of monthly mean 500-hPa height anomalies was accounted for by the Southern Annular Mode. Empirical orthogonal function analysis showed that the next two most important modes looked similar to those associated with El Nino-Southern Oscillation (ENSO). However, correlations of the associated time series with those of the coupled model's tropical sea surface SSTs were much smaller than for the observed present-day ENSO correlations.