Exploring southern hemisphere climates

The rationale for data studies of the southern hemisphere circulation is addressed. A brief account is given of hemispheric climatic records from the proxy data of the pre-instrumental period to space-derived information. The limitations imposed by the nature of the records on studies of past seasonal and interannual variability are pointed out; some techniques for the examination of the earlier records are reviewed; and current methods of continued monitoring of the circulation are described. Studies of the broadscale sea surface temperature — atmosphere interrelation, in particular those of the Southern Oscillation, are identified as an important area of current research. As an example, the widespread and persistent anomalies of sea surface temperature (SST) in the eastern Indian and southwest Pacific oceans associated with extreme anomalies of Australian annual rainfall are described, as well as the concurrent out of phase SST relationships with the eastern South Pacific. Problems in the investigation of the other major surface feature of considerable variability and potential importance in atmospheric forcing, viz. the Antarctic sea ice, are also described.