Decadal Disruption of the QBO by Tropical Volcanic Supereruptions

Abstract The Los Chocoyos (14.6°N, 91.2°W) supereruption happened ∼75,000 years ago in Guatemala and was one of the largest eruptions of the past 100,000 years. It emitted enormous amounts of sulfur, chlorine, and bromine, with multi‐decadal consequences for the global climate and environment. Here, we simulate the impact of a Los Chocoyos‐like eruption on the quasi‐biennial oscillation (QBO), an oscillation of zonal winds in the tropical stratosphere, with a comprehensive aerosol chemistry Earth System Model. We find a ∼10‐year disruption of the QBO starting 4 months post eruption, with anomalous easterly winds lasting ∼5 years, followed by westerlies, before returning to QBO conditions with a slightly prolonged periodicity. Volcanic aerosol heating and ozone depletion cooling leads to the QBO disruption and anomalous wind regimes through radiative changes and wave‐mean flow interactions. Different model ensembles, volcanic forcing scenarios and results of a second model back up the robustness of our results.