RECENT APPARENT CHANGES IN RELATIONSHIPS BETWEEN THE EL-NINO - SOUTHERN OSCILLATION AND AUSTRALIAN RAINFALL AND TEMPERATURE

High quality historical temperature and rainfall data sets have been u sed to produce time series of annual rainfall and temperature, average d over Australia. The relationships between these series, and with the Southern Oscillation Index, have been examined. A change in the relat ionships between the variables appeared in the early 1970s. Since then , for any value of the SOI or rainfall, maximum temperature has tended to be higher than previously. Likewise, rainfall, for any value of th e SOI, has tended to be greater than would have been expected for such an SOI value in previous years. Artificial changes, such as changes i n instrumentation, seem unlikely to account for these observed changes in relationships. Model experiments have duplicated some of the chang es in the relationships. Increased Indian Ocean temperatures may be th e causal factor underlying these changes.