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Unraveling the Dominant Influence of ENSO over IOD on Australian Springtime Climate Variability Using a Pacemaker Modeling Approach

delete2026-04-01
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PRE
AI
L
Liu, Ying Lung *
E
Evans, Jason P.
DOI:10.1175/JCLI-D-25-0142.1delete
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Abstract

Abstract

En 中文
This study employs the Conformal Cubic Atmospheric Model (CCAM) to investigate the independent influ-ences of El Ni & ntilde;o-Southern Oscillation (ENSO) and Indian Ocean dipole (IOD) on Australian springtime rainfall and temperature variability. A pacemaker-style experiment was conducted using a variable-resolution configuration with similar to 20-km resolution over Australia. Three 10-member ensemble simulations were performed: a control (CTRL) run, an ENSOremoved (noENSO) run with tropical Pacific ENSO-driven sea surface temperature (SST) variability removed via empirical orthogonal function (EOF) filtering, and an IOD-removed (noIOD) run with IOD-related SST variability removed. The results demonstrate that ENSO is the primary driver of Australian rainfall and temperature variability, dominating patterns traditionally linked to both ENSO and IOD. In the noENSO experiment, correlations between climate variables and ENSO/IOD indices are significantly reduced, while in noIOD, the correlations are only slightly weakened. This underscores the limited role of IOD in the CTRL simulation interannual variability. The circulation analysis reveals that removing ENSO-associated SST variability over the tropical Pacific also eliminates circulation responses beyond the tropical Pacific, confirming that ENSO primarily affects Australian climate variability via teleconnections. Additionally, the sensitivity of rainfall correlations to internal variability highlights the importance of ensemble experiments for robustly assessing ENSO/IOD impacts on regional climate dynamics. However, uncertainties remain regarding the interaction between eastern Pacific El Ni & ntilde;o and positive IOD events, warranting further investigation.
Keywords:
Australia
ENSO
Climate variability
Climate models
Interannual variability
Internal variability

Journal

Journal of Climate cover
Journal of Climate
IF:
4
Papers:
1.4W
Citations:
5.9W

Organization

U
university of new south wales sydney
Scholars:
2.1K
Papers: 941
Citations: 0
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