Weakening Atlantic Nio-Pacific connection under greenhouse warming.
Additional Document Info
Sea surface temperature variability in the equatorial eastern Atlantic, which is referred to as an Atlantic Nio (Nia) at its warm (cold) phase and peaks in boreal summer, dominates the interannual variability in the equatorial Atlantic. By strengthening of the Walker circulation, an Atlantic Nio favors a Pacific La Nia, which matures in boreal winter, providing a precursory memory for El Nio-Southern Oscillation (ENSO) predictability. How this Atlantic impact responds to greenhouse warming is unclear. Here, we show that greenhouse warming leads to a weakened influence from the Atlantic Nio/Nia on the Pacific ENSO. In response to anomalous equatorial Atlantic heating, ascending over the equatorial Atlantic is weaker due to an increased tropospheric stability in the mean climate, resulting in a weaker impact on the Pacific Ocean. Thus, as greenhouse warming continues, Pacific ENSO is projected to be less affected by the Atlantic Nio/Nia and more challenging to predict.