The non-linear impact of El Nino, La Nina and the Southern Oscillation on seasonal and regional Australian precipitation

Abstract

The relationship between El Niño-Southern Oscillation (ENSO) indices and precipitation (P) in some parts of Australia has previously been shown to be non-linear on annual and seasonal time scales. Here we examine the relationship between P and the Southern Oscillation Index (SOI) at all Australian locations and in all seasons. We show that in many Australian regions, there is more-than-expected P during strong La Niña years (SOI>13), but less-than-expected drying during strong El Niño years (SOI