Information Flow between ENSO and Other Tropical Ocean Basins

Tropical basin interactions play a crucial role in shaping global climate variability, including modulating ENSO events. However, the relative importance of ENSO’s influence on other tropical ocean basins and their feedback on ENSO remains debated. Through analyzing observational data and CMIP6 outputs, we employed the Liang–Kleeman information flow analysis to explore causal relationships between ENSO and other climate modes in the tropical Indian and Atlantic Oceans. Our results reveal significant two-way interactions between ENSO and the Indian Ocean Dipole (IOD) as well as the North Tropical Atlantic (NTA). On the other hand, while the Atlantic Niño promotes La Niña development, ENSO’s influence on the Atlantic Niño is limited and inconsistent. Furthermore, the Ningaloo Niño, the dominant interannual climate variability mode in the southeast Indian Ocean, significantly impacted the tropical Pacific before 2000, whereas ENSO’s influence has dominated afterward. Compared to observational data, climate models tend to overestimate ENSO’s impact on other climate modes while underrepresenting the reverse effects. These findings underscore the critical need to correct such model biases to enhance the simulation and prediction of ENSO.