EGU21-10482, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

The relationship between the El Niño Southern Oscillation and Australian monsoon rainfall on decadal time-scales

Hanna Heidemann1,2, Joachim Ribbe2, Benjamin J. Henley3,4,5, Tim Cowan1,6, Christa Pudmenzky1, Roger Stone1, and David H. Cobon1
Hanna Heidemann et al.
  • 1Centre for Applied Climate Sciences, University of Southern Queensland, Toowoomba, Australia
  • 2School of Sciences, Faculty of Health, Engineering and Sciences, University of Southern Queensland, Toowoomba, Australia
  • 3School of Earth, Atmosphere and Environment, Monash University, Melbourne, Australia
  • 4School of Earth Sciences, University of Melbourne, Melbourne, Australia
  • 5ARC Centre of Excellence for Climate Extremes, Monash University, Melbourne Australia
  • 6Bureau of Meteorology, Melbourne, Australia

This research analyses the observed relationship between eastern and central Pacific El Niño Southern Oscillation (ENSO) events and Australian monsoon rainfall (AUMR) on a decadal timescale during the December to March monsoon months. To assess the decadal influence of the different flavours of ENSO on the AUMR, we focus on the phases of the Interdecadal Pacific Oscillation (IPO) over the period 1920 to 2020.  The AUMR is characterized by substantial decadal variability, which appears to be linked to the positive and negative phases of the IPO. During the past two historical negative IPO phases, significant correlations have been observed between central Pacific sea surface temperature (SST) anomalies and AUMR over both the northeast and northwest of Australia. This central Pacific SST-AUMR relationship has strengthened from the first negative IPO phase (mid-1940s to the mid-1970s) to the second (late 1990s to mid-2010s), while the eastern Pacific SST-AUMR influence has weakened. Composite rainfall anomalies over Australia reveal a different response of AUMR to central Pacific El Niño/La Niña and eastern Pacific La Niña events during positive IPO and negative IPO phases. This research clearly shows that ENSO's influence on AUMR is modulated by Pacific decadal variability, however this teleconnection, in itself, can change between similar decadal Pacific states.  Going forward, as decadal prediction systems improve and become more mainstream, the IPO phase could be used as a potential source for decadal predictability of the tendency of AUMR.  

How to cite: Heidemann, H., Ribbe, J., Henley, B. J., Cowan, T., Pudmenzky, C., Stone, R., and Cobon, D. H.: The relationship between the El Niño Southern Oscillation and Australian monsoon rainfall on decadal time-scales, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10482,, 2021.

Corresponding displays formerly uploaded have been withdrawn.