Evaluation Of Simulation Capability And Future Projection Of AMO And PDO In CMIP5 Models

Based on the observed sea surface temperature(SST)data from 1880-2009 and the simulation SST datasets under four scenarios(piControl,historical,RCP2.6,RCP4.5)in the CMIP5 models,we evaluated the simulation capabilities of the Atlantic Multidecadal Oscillation(AMO)and the Pacific Decadal Oscillation(PDO)in CMIP5 models and further investigated their future projection under different warming scenarios.The results showed that that the multi-model ensemble can reproduce the interdecadal temperature center of sea surface temperature in the North Pacific,East Pacific,and North Atlantic in the historical and piControl scenarios,but the amplitudes of the two modes are weak in the simulation.Especially,the PDO mode has a weaker reproducibility in the East Pacific.By evaluating the spatial and temporal characteristics of AMO and PDO of in historical scenario,we ranked the ability of models in simulation AMO and PDO and suggested CESM1-CAM5,FGOALS-g2,GISS-E2-H-CC,MIROC5,NorESM1-ME are five better models.The multi-model ensemble is best.Under different warming scenarios,the spatial characteristics of AMO and PDO are basically the same,and the amplitude difference is not obvious in different warming scenarios,and interdecadal signals mainly exist in the North Pacific and North Atlantic regions.However,with the increase of global warming,the two modes have the characteristics of reduced variance contribution,especially for AMO mode.This phenomenon may be related to the fact that AMO is internal variability.And the contribution rate of variance is related to the amplitude of regional ocean temperature oscillations.The above analysis provides us some new clues for further understanding of the changing the two interdecadal modes under the warming scenario.