第一届未来大气科学论坛

This study investigates the future changes in the impact of El Niño–Southern Oscillation (ENSO) on the Southeast Asian summer monsoon (SEASM) during the post-ENSO summer under greenhouse warming, using simulations from 28 coupled models participating in Phase 6 of the Coupled Model Intercomparison Project (CMIP6). The multimodel ensemble mean of CMIP6 models projects an enhanced response of the SEASM to ENSO in a warmer climate, primarily due to the weakened sea surface temperature (SST) anomalies over the western equatorial Pacific (WEP) during the post-El Niño summer. Compared to the present climate, the WEP SST anomalies associated with El Niño decay more rapidly and dissipate by the following summer in a warmer climate, leading to an intensified ENSO-induced SEASM anomaly via an enhanced zonal SST anomaly gradient between the tropical Indian Ocean and the WEP. Further analysis reveals that the weakened WEP SST anomalies are mainly attributed to stronger latent heat damping, driven by increased surface wind speed anomalies. This change is linked to an eastward shift of the anomalous Walker circulation induced by an El Niño-like SST warming pattern in the tropical Pacific under global warming. Additionally, the weakening of the climatological Walker circulation slows down the climatological zonal ocean currents, further reducing the WEP SST anomalies by weakening the advection of anomalous temperature by the mean current.
 

Asian Summer Monsoon,El Nino/Southern Oscillation,Global warming