ENSO and NAO Linkage to Strong Volcanism and Associated Post-Volcanic High-Latitude Winter Warming

Abstract

High-latitude winter warming was observed following strong tropical volcanism, which has long been believed to be due to the volcanic-induced positive North Atlantic Oscillation (NAO) phase. However, recent works argue that this warming is caused by El Niño–Southern Oscillation (ENSO) variability instead of volcanoes. Moreover, some studies further argue that El Niño and volcanoes work together to produce this post-volcanic NAO winter warming. To better understand these arguments on post-volcanic high-latitude winter warming, we conducted ENSO-preconditioned volcanic experiments. Our simulations strongly suggest that the post-eruption Eurasian winter warming is caused by a post-eruption positive NAO phase and not by coexisting ENSO-preconditioned variability. Additionally, we find that the El Niño-preconditioned volcanic eruption enhances the El Niño phase; however, the neutral and La Niña-preconditioned eruptions do not lead to an ENSO–like response. These findings are helpful to better understand volcanic-induced circulation impacts and have important implications for the interpretation of model results and post-volcanic prediction.