Warming patterns affect El Niño diversity in CMIP5 and CMIP6 models

Mandy B. Freund; Josephine R. Brown; Benjamin J. Henley; David J. Karoly; Jaclyn N. Brown

doi:10.1175/JCLI-D-19-0890.1

Warming patterns affect El Niño diversity in CMIP5 and CMIP6 models

Mandy B. Freund, Josephine R. Brown, Benjamin J. Henley, David J. Karoly, Jaclyn N. Brown

School of Earth Atmosphere and Environment

Research output: Contribution to journal › Article › Research › peer-review

14 Citations (Scopus)

Abstract

Given the consequences and global significance of El Niño-Southern Oscillation (ENSO) events it is essential to understand the representation of El Niño diversity in climate models for the present day and the future. In recent decades, El Niño events have occurred more frequently in the central Pacific (CP). Eastern Pacific (EP) El Niño events have increased in intensity. However, the processes and future implications of these observed changes in El Niño are not well understood. Here, the frequency and intensity of El Niño events are assessed in models from phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6), and results are compared to extended instrumental and multicentury paleoclimate records. Future changes of El Niño are stronger for CP events than for EP events and differ between models. Models with a projected La Niña-like mean-state warming pattern show a tendency toward more EP but fewer CP events compared to models with an El Niño-like warming pattern. Among the models with more El Niño-like warming, differences in future El Niño can be partially explained by Pacific decadal variability (PDV). During positive PDV phases, more El Niño events occur, so future frequency changes are mainly determined by projected changes during positive PDV phases. Similarly, the intensity of El Niño is strongest during positive PDV phases. Future changes to El Niño may thus depend on both mean-state warming and decadal-scale natural variability.

Original language	English
Pages (from-to)	8237-8260
Number of pages	24
Journal	Journal of Climate
Volume	33
Issue number	19
DOIs	https://doi.org/10.1175/JCLI-D-19-0890.1
Publication status	Published - 1 Oct 2020

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@article{a82ab0bb0e6c4085806418ff9b018b24,

title = "Warming patterns affect El Ni{\~n}o diversity in CMIP5 and CMIP6 models",

abstract = "Given the consequences and global significance of El Ni{\~n}o-Southern Oscillation (ENSO) events it is essential to understand the representation of El Ni{\~n}o diversity in climate models for the present day and the future. In recent decades, El Ni{\~n}o events have occurred more frequently in the central Pacific (CP). Eastern Pacific (EP) El Ni{\~n}o events have increased in intensity. However, the processes and future implications of these observed changes in El Ni{\~n}o are not well understood. Here, the frequency and intensity of El Ni{\~n}o events are assessed in models from phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6), and results are compared to extended instrumental and multicentury paleoclimate records. Future changes of El Ni{\~n}o are stronger for CP events than for EP events and differ between models. Models with a projected La Ni{\~n}a-like mean-state warming pattern show a tendency toward more EP but fewer CP events compared to models with an El Ni{\~n}o-like warming pattern. Among the models with more El Ni{\~n}o-like warming, differences in future El Ni{\~n}o can be partially explained by Pacific decadal variability (PDV). During positive PDV phases, more El Ni{\~n}o events occur, so future frequency changes are mainly determined by projected changes during positive PDV phases. Similarly, the intensity of El Ni{\~n}o is strongest during positive PDV phases. Future changes to El Ni{\~n}o may thus depend on both mean-state warming and decadal-scale natural variability.",

author = "Freund, {Mandy B.} and Brown, {Josephine R.} and Henley, {Benjamin J.} and Karoly, {David J.} and Brown, {Jaclyn N.}",

note = "Funding Information: Acknowledgments. We thank Eun-Pa Lim and Kavina Dayal for their helpful comments on earlier versions of the manuscript. We acknowledge the World Climate Research Programme{\textquoteright}s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modelling groups (listed in Table A1 of this paper) for producing and making available their model outputs. Josephine Brown and Benjamin Henley are affiliated ARC Centre of Excellence for Climate Extremes. David Karoly is supported through funding from the Earth Systems and Climate Change Hub of the Australian Government{\textquoteright}s National Environmental Science Program. Benjamin Henley receives funds from an Australian Research Council Linkage Project (LP150100062) with Melbourne Water, the Victorian Department of Environment, Land, Water and Planning, and the Australian Bureau of Meteorology. Publisher Copyright: {\textcopyright} 2020 American Meteorological Society. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.",

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N1 - Funding Information: Acknowledgments. We thank Eun-Pa Lim and Kavina Dayal for their helpful comments on earlier versions of the manuscript. We acknowledge the World Climate Research Programme’s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modelling groups (listed in Table A1 of this paper) for producing and making available their model outputs. Josephine Brown and Benjamin Henley are affiliated ARC Centre of Excellence for Climate Extremes. David Karoly is supported through funding from the Earth Systems and Climate Change Hub of the Australian Government’s National Environmental Science Program. Benjamin Henley receives funds from an Australian Research Council Linkage Project (LP150100062) with Melbourne Water, the Victorian Department of Environment, Land, Water and Planning, and the Australian Bureau of Meteorology. Publisher Copyright: © 2020 American Meteorological Society. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

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N2 - Given the consequences and global significance of El Niño-Southern Oscillation (ENSO) events it is essential to understand the representation of El Niño diversity in climate models for the present day and the future. In recent decades, El Niño events have occurred more frequently in the central Pacific (CP). Eastern Pacific (EP) El Niño events have increased in intensity. However, the processes and future implications of these observed changes in El Niño are not well understood. Here, the frequency and intensity of El Niño events are assessed in models from phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6), and results are compared to extended instrumental and multicentury paleoclimate records. Future changes of El Niño are stronger for CP events than for EP events and differ between models. Models with a projected La Niña-like mean-state warming pattern show a tendency toward more EP but fewer CP events compared to models with an El Niño-like warming pattern. Among the models with more El Niño-like warming, differences in future El Niño can be partially explained by Pacific decadal variability (PDV). During positive PDV phases, more El Niño events occur, so future frequency changes are mainly determined by projected changes during positive PDV phases. Similarly, the intensity of El Niño is strongest during positive PDV phases. Future changes to El Niño may thus depend on both mean-state warming and decadal-scale natural variability.

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JO - Journal of Climate

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Warming patterns affect El Niño diversity in CMIP5 and CMIP6 models

Abstract

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ARC Centre of Excellence for Climate Extremes

Megadrought likelihood and its water resource impacts in Australia

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Warming patterns affect El Niño diversity in CMIP5 and CMIP6 models

Abstract

UN SDGs

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Projects

ARC Centre of Excellence for Climate Extremes

Megadrought likelihood and its water resource impacts in Australia

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