Evolution and Prediction of Two Extremely Strong Atlantic Niños in 2019–2021: Impact of Benguela Warming

Abstract

As El Niño's little brother in the equatorial Atlantic Ocean, Atlantic Niño affects the climate variability in the tropical Atlantic Ocean and the vicinity. In 2019–2021, two extremely strong Atlantic Niños occurred with peaks in January 2020 and July 2021, respectively. The coupling between the ocean and atmosphere associated with the Atlantic Niños is similar to that associated with El Niño-Southern Oscillation. Both the Atlantic Niños were triggered and modulated by a Benguela Niño-like warming, through inducing wind stress anomalies in the South and equatorial Atlantic Ocean. In addition to the atmosphere-ocean coupling at intraseasonal-interseasonal time scales, interdecadal and longer time scale variation amplified the Atlantic Niños. Model predictions only capture the evolution of the Atlantic Niños at a 1-month lead, consistent with the low prediction skill for sea surface temperature anomalies in the tropical Atlantic Ocean.