Influence of SOI, DMI and Niño3.4 on South Australian rainfall

Abstract

The influences of climate drivers (SOI, DMI and Nino3.4) on South Australian (SA) rainfall are investigated in this study. Recent records of monthly rainfall and climate driver index values from 1981 to 2010 were analysed for 53 rainfall stations, located across eight SA natural resources management (NRM) regions. The Pearson, Kendall and Spearman correlation tests were applied between rainfall and climate drivers and between the climate drivers themselves. Both SA summer (December to February) and autumn (March to May) rainfalls were found not significantly influenced by climate indices. Winter rainfall in the south and east parts of SA was found strongly influenced by both SOI and DMI, particularly in July and August. Both SOI and DMI are inter-correlated in winter. Spring rainfall was found significantly influenced by DMI in the south and east parts of SA, particularly in September and October. In terms of ENSO phenomena, whilst both SOI and Nino3.4 are correlated, SOI was found more to be influential than Nino3.4 for SA winter and spring rainfall. Outcomes of the study are useful for stochastic rainfall generation and for developing downscaling techniques to generate rainfall projections in the region.