ALL-INDIA SUMMER MONSOON RAINFALL AND SEA-SURFACE TEMPERATURES AROUNDNORTHERN AUSTRALIA AND INDONESIA

The relationship between Indian summer (June-September) monsoon rainfa ll and sea surface temperatures around northern Australia-Indonesia ha s been explored using data from 1949 to 1991. Warm sea surface tempera tures are generally associated with a good monsoon; a poor monsoon is usually accompanied and preceded by low sea surface temperatures. This finding confirms, on independent data, a suggestion made a decade ago . This study also confirms a relationship between changes in Darwin pr essure and Indian monsoon rainfall. These two relationships appear to provide a method for predicting Indian summer monsoon rainfall a month or two before the onset of the monsoon season. Two predictors (April sea surface temperatures and the change in Darwin pressure from Januar y to April) together account for about 50% of the variance in Indian m onsoon rainfall if the data are adjusted to remove possible artificial trends in the ocean temperatures. The northern Australia-Indonesia re gion is clearly an important component in the large-scale interaction between the Indian monsoon and the El Nino/Southern Oscillation.