Trascasa-Castro, P., Maycock, A.C. orcid.org/0000-0002-6614-1127, Ruprich-Robert, Y. et al. (2 more authors) (2023) Atlantic Multidecadal Variability modulates the climate impacts of El Niño–Southern Oscillation in Australia. Environmental Research Letters, 18 (8). 084029. ISSN 1748-9326
Abstract
Atlantic Multidecadal Variability (AMV) modulates El Niño–Southern Oscillation (ENSO) dynamics. Here, we explore the effect of warm (AMV+) and cold (AMV−) AMV conditions on the austral summer teleconnection of ENSO to Australia using idealized simulations performed with the NCAR-CESM1 model. AMV+ strengthens the mean and extreme precipitation and temperature responses to El Niño in south-western Australia and weakens the mean precipitation and temperature impacts in north-eastern Australia. The modulation of La Niña impacts by AMV is asymmetric to El Niño, with a weakening of the mean and extreme precipitation and temperature responses in eastern Australia. Decomposing the total difference in ENSO response between AMV phases, we find that the signals are mainly explained by the direct AMV modulation of ENSO and its teleconnections rather than by changes in background climate induced by AMV. The exception is ENSO-driven fire impacts, where there is a significant increase in burned area in south-eastern Australia only when El Niño and AMV+ co-occur. However, modulation of ENSO between AMV+ and AMV− does offset ∼37% of the decrease in burned area extent during La Niña summers. The altered surface climate response to ENSO in Australia by AMV is attributed to variations in large-scale atmospheric circulation. Under AMV+, there is increased subsidence over western Australia during El Niño associated with a westward shift of the local Walker circulation. A weakening of the upwelling branch of the local Hadley circulation over north-eastern Australia is responsible for the weakening of La Niña impacts in AMV+, accompanied by a strengthening of subsidence in south central Australia due to a weakening of the local Hadley circulation, amplifying La Niña impacts over this region. The results suggest the potential for AMV to drive multidecadal variability in ENSO impacts over Australia.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Author(s). This is an open access article under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Atlantic Multidecadal Variability; ENSO; teleconnections; climate impacts; Australia |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Sep 2023 11:02 |
Last Modified: | 06 Sep 2023 11:38 |
Status: | Published |
Publisher: | IOP Publishing |
Identification Number: | 10.1088/1748-9326/ace920 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:203097 |
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Licence: CC-BY 4.0