Influence of ENSO and the IOD on Atmospheric Fronts and Frontal Precipitation across Australia

Over the past few decades, Southeast Australia has experienced severe regional climatic events, including devastating floods and some of the most extreme droughts on record, linked in part to influences from both the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). In this manuscript, the extent to which ENSO-IOD driven rainfall anomalies are communicated specifically through variations in atmospheric fronts is quantified. Consistent with previous studies, the most extreme wet (dry) conditions result from the co-occurrence of La Niña-Negative IOD (El Niño-Positive IOD). With maximum anomalous wet and dry conditions in southeast Australia during Austral winter, it is found that most of these precipitation anomalies result from changes to the frontal precipitation associated with the passing of atmospheric fronts. These anomalies accompany changes in both the frequency of atmospheric fronts as well as the precipitation rate associated with those fronts. Interestingly, the distribution in the dynamic strength of individual fronts remains relatively unchanged. Instead, the variability in atmospheric fronts and their associated precipitation appears to be related to latitudinal fluctuations in the eddy-driven jet.