Weakened interannual variability of the contrast in rainfall between the eastern equatorial Pacific and equatorial Atlantic since 2000

Recent studies suggest that the interannual variability in the tropical Pacific associated with the El Niño–Southern Oscillation has weakened since 2000. In this study, the authors report that the interannual variability of the contrast in rainfall between the eastern equatorial Pacific and equatorial Atlantic has also weakened remarkably since 2000, attributable to the weakened interannual variability in the zonal sea surface temperature gradient between the eastern equatorial Pacific and equatorial Atlantic and in the associated equatorial low-level zonal wind across South America linking the two ocean basins. Diagnosis of a column-integrated moisture budget indicates that the weakening in the interannual variability of the contrast in rainfall is primarily attributable to the changes in moisture convergence associated with vertical motion. The results highlight the clear weakened interannual variability in the coupled equatorial Pacific–Atlantic climate system since 2000, including the Pacific El Niño, Atlantic Niño, equatorial zonal wind across South America, and rainfall over the eastern equatorial Pacific and equatorial Atlantic.