Weakening of Northwest Pacific Anticyclone Anomalies during Post–El Niño Summers under Global Warming

AbstractThe northwest Pacific anticyclone (NWPAC) anomalies during post–El Nino summers are a key predictor of the summer climate in East Asia and the northwestern Pacific (NWP). Understanding how this will change under global warming is crucial to project the changes in the variability of the northwest Pacific summer monsoon. Outputs from 18 selected coupled models from phase 5 of the Coupled Model Intercomparison Project show that the anomalous NWPAC response to El Nino will likely be weakened under global warming, which is attributed to the decreased zonal contrast between the tropical Indian Ocean (TIO) warming and the NWP cooling during post–El Nino summers. Under global warming, the NWPAC anomalies during the El Nino mature winter are weakened because of decreased atmospheric circulation in response to El Nino–Southern Oscillation (ENSO), which leads to the weakening of local air–sea interaction and then decreases the cold NWP SST anomalies. Furthermore, the decreased surface heat flux anomalies, th...