INDIAN-OCEAN SEA-SURFACE TEMPERATURE PATTERNS AND AUSTRALIAN WINTER RAINFALL

Indian Ocean sea-surface temperatures (SSTs) for the period 1950-1988 are analysed using principal component analysis, and their relationships with Australian winter rainfall totals for the period 1950-1979 are studied using regression analysis. As has been demonstrated by others, significant simultaneous correlations exist between the dominant patterns in the Indian Ocean and the wintertime rainfall over a large part of Australia. There is also evidence of significant correlations between autumn SST patterns and winter rainfall. These relationships are tested using multiple linear-regression-based predictions of winter rainfall categories for the period 1980-1988. Skill is quantified in terms of categorical predictions. Predictions based on the autumn SSTs exhibit more skill than those based on the autumn SOI, but much less than predictions based on the concurrent winter indices.