Changes in El Niño and La Niña teleconnections over North Pacific–America in the global warming simulations
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The change in the teleconnections of both El Niño and La Niña over the North Pacific and American regions due to a future greenhouse warming has been analyzed herein by means of diagnostics of the Intergovernmental Panel on Climate Change-Fourth Assessment Report (IPCC-AR4) coupled general circulation models (CGCMs). Among the IPCC-AR4 CGCM simulations, the composites of the eight-member multimodel ensemble are analyzed. In most CGCMs, the tropical Pacific warming due to the increase of CO2 concentration in the atmosphere promotes the main convection centers in the equatorial Pacific associated with both El Niño and La Niña to the east. The eastward shift of the convection center causes a systematic eastward shift of not only El Niño but also La Niña teleconnection patterns over the North Pacific and America, which is demonstrated in the composite maps of 500 hPa circulation, surface temperature, and the precipitation against El Niño and La Niña, as observed in a comparison between the pre-industrial and CO2 doubling experiments. Thus, a systematic eastward migration of convection centers in the tropical Pacific associated with both El Niño and La Niña due to a future global warming commonly causes the eastward shift of the atmospheric teleconnection patterns over the Northern Hemisphere.
KeywordsTeleconnection Pattern Cold Tongue Greenhouse Warming Multimodel Ensemble Atmospheric Teleconnection
We acknowledge the modeling groups for providing their data for analysis, the Program for Climate model Diagnosis and Intercomparison for collecting and archiving the model output, and the JSC/CLIVAR Working Group on Coupled Modeling for organizing the model data analysis activity. The multimodel data archive is supported by the Office of Science, US Department of Energy. This research was supported by “National Comprehensive Measures against Climate Change” Program by Ministry of Environment, Korea (grant no. 1600-1637-301-210-13), and Brain Korea 21 Project. J.-S. Kug is supported by KORDI (PE98417, PP00720).
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