Impact of equatorial Atlantic variability on ENSO predictive skill

El Nino-Southern Oscillation (ENSO) is a key mode of climate variability with worldwide climate impacts. Recent studies have highlighted the impact of other tropical oceans on its variability. In particular, observations have demonstrated that summer Atlantic Ninos (Ninas) favor the development of Pacific Ninas (Ninos) the following winter, but it is unclear how well climate models capture this teleconnection and its role in defining the seasonal predictive skill of ENSO. Here we use an ensemble of seasonal forecast systems to demonstrate that a better representation of equatorial Atlantic variability in summer and its lagged teleconnection mechanism with the Pacific relates to enhanced predictive capacity of autumn/winter ENSO. An additional sensitivity study further shows that correcting SST variability in equatorial Atlantic improves different aspects of forecast skill in the Tropical Pacific, boosting ENSO skill. This study thus emphasizes that new efforts to improve the representation of equatorial Atlantic variability, a region with long standing systematic model biases, can foster predictive skill in the region, the Tropical Pacific and beyond, through the global impacts of ENSO. El Nino-Southern Oscillation (ENSO) is a key mode of climate variability with worldwide climate impacts. Here, the authors show that improved representation of summer equatorial Atlantic variability and its lagged teleconnection mechanism with the Pacific, relates to enhanced predictive capacity of autumn/winter ENSO.

Automated summary

Research shows that improving the representation of summer equatorial Atlantic variability and its lagged teleconnection mechanism with the Pacific enhances the predictive capacity of autumn/winter ENSO.