Improved Simulation of ENSO Variability Through Feedback From the Equatorial Atlantic in a Pacemaker Experiment

The tropical Pacific Ocean interacts with the tropical Atlantic Ocean on interannual time scales. However, most coupled climate models misrepresent and/or underestimate these teleconnections, which have important implications on the periodicity of the El Niño‐Southern Oscillation (ENSO). Imposing the observed sea surface temperature over the tropical Atlantic from 1970 onwards, a pacemaker experiment is constructed using the second version of the Australian Community Climate and Earth System Simulator Coupled Model (ACCESS‐CM2). Compared with control runs which reasonably simulate the interaction between ENSO and the north tropical Atlantic variability, the pacemaker experiment significantly improves the impact of the Atlantic Niño/Niña on ENSO. This enhanced teleconnection contributes to a more realistic ENSO periodicity compared with the control runs, thus suggesting that capturing the influence from equatorial Atlantic variability is important for an improved ENSO simulation.