The Madden-Julian oscillation and Southern Hemisphere circulation anomalies during southern summer.

A lifecycle of the Madden-Julian oscillation (MJO) is constructed from an EOF analysis of 24 southern summers of satellite-measured outgoing longwave radiation data from 1974-97. Corresponding circulation anomalies are calculated from NCEP-NCAR reanalyses and MSU temperature data. The eastward shift of the MJO convective anomalies from the Australian region to the South Pacific convergence zone is consistent with a subtropical Rossby wave propagation mechanism. Extratropical circulation anomalies show a pronounced standing oscillation. Rossby wave diagnostics and baroclinic model integrations are used to interpret these observations.