Quantifying ENSOs Impact on Australia’s Regional Monthly Rainfall Risk

Quantifying ENSOs Impact on Australia’s Regional Monthly Rainfall Risk

March 21, 2024

The El Niño‐Southern Oscillation (ENSO) is considered an important driver of rainfall variability in Australia, amongst many other global locations. Despite knowledge of the expected modulation of seasonal rainfall by ENSO, there is no consistently used method to quantify the role that specific ENSO events play in driving the observed anomalous rainfall. In this manuscript we adapt the Fraction of Attributable Risk (FAR) method, commonly used to identify the anthropogenic impact on a particular event, to quantify the impact of ENSO on the occurrence of monthly rainfall anomalies. We also explicitly calculate the ENSO induced change in risk and the FAR for all observed spring rainfall rates for our eastern Australian regions. A prominent role for ENSO in driving the large spring 2022 rainfall anomalies is identified. Though we choose to focus on ENSOs impact on rainfall in various Eastern Australian regions, the results are applicable to other climate modes, regions and climatic variables.

Read more: McGregor, S.Gallant, A., & van Rensch, P. (2024). Quantifying ENSOs impact on Australia’s regional monthly rainfall riskGeophysical Research Letters51, e2023GL106298. https://doi.org/10.1029/2023GL106298

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