Projected Future Changes of Ningaloo Niño under Global Warming

Abstract Ningaloo Niño is an important climate mode in the southeast Indian Ocean with far-reaching impacts on the climate and marine environment, but how Ningaloo Niño will change under global warming remains unclear. This study investigates the response of Ningaloo Niño to global warming using the Community Earth System Model Large Ensemble projections and the Coupled Model Intercomparison Project phase 6 model simulations. We find that the Ningaloo Niño will have a stronger magnitude in the second half of the twenty-first century under the high greenhouse gas emission scenario, with nearly 60% of models showing a 1-month delay in its broadened seasonal peak. A mixed layer heat budget analysis indicates that the meridional advective feedback is the dominant driver for the Ningaloo Niño changes, with additional contributions from changes in latent heat flux forcing. The strengthening of the Leeuwin Current during the Ningaloo Niño events and the decrease in latent heat loss are closely associated with enhanced coastal Bjerknes feedback, with possible contributions from the wind–evaporation–SST feedback. Furthermore, given the amplification of El Niño–Southern Oscillation (ENSO) and the increase of specific humidity saturation under global warming, ENSO-related remote influences on the enhancement of Ningaloo Niño activity need further investigation.