Present and future relationship between the East Asian winter monsoon and ENSO: Results of CMIP5

The East Asian winter monsoon (EAWM) is the key indicator for the cold surge activities, influencing East Asia during winter, and the El Nino-Southern Oscillation (ENSO) is one of the major predictors for the EAWM seasonal forecast, although their relationship has been thought to be unstable. This study evaluated the capability of 30 state-of-the-art climate models among the Coupled Model Intercomparison Project Phase 5 (CMIP5) in reproducing the weakening of ENSO-EAWM relationship around the mid-1970s and discussed further the ENSO-EAWM relationship in the 21st century under the RCP4.5 scenario. Evaluation of climate models based on the CMIP5 simulations of the 20th century indicates that 10 out of 30 climate models are capable to reproduce the overall interdecadal shift of the ENSO-EAWM relationship during 1950-2003. However, the temporal evolution of the ENSO-EAWM relationship is difficult to be captured by most models. There are three CMIP5 models (CCSM4, GFDL-CM3, and MPI-ESM-LR) that can well capture the continuous weakening of the ENSO-EAWM relationship around 1976. Based on the three CMIP5 models' simulations, the ENSO-EAWM connection tends to be enhanced in the near term (2016-2046), then weakened, and barely significant during 2047-2067. Finally, the ENSO-EAWM connection appears to largely recover during 2068-2099 but be weaker than that during 2016-2046. We also analyzed the associated processes in the Pacific-Asia-Arctic areas based on the model simulations. It is indicated that there seems to be a seesaw relationship between the ENSO's impact and the influence of the Arctic Oscillation on the EAWM during the 21st century.