Be the first to like this
The relationship between seasonal aggregate rainfall and large scale climate modes, particularly the El Niño-Southern Oscillation (ENSO), has been the subject of a significant and on-going research effort. However, relatively little is known about how the character of individual rainfall events varies as a function of each of these climate modes. This study investigates the change in rainfall occurrence, intensity, and storm inter-event time at both daily and sub-daily timescales in East Australia, as a function of indices for ENSO, the Indian Ocean Dipole (IOD), and the Southern Annular Mode (SAM), with a focus on the cool season months. Long record data sets have been used to sample large variety of climate events for better statistical significance. Results using both the daily and sub-daily rainfall data sets consistently show that it is the occurrence of rainfall events, rather than the average intensity of rainfall during the events, which is most strongly influenced by each of the climate modes. This is shown to be most likely associated with changes to the time between wet spells. Furthermore, it is found that despite the recent attention in the research literature on other climate modes, ENSO remains the leading driver of rainfall variability over East Australia, particularly further inland during the winter and spring seasons.