Investigating the Climatic Impacts of Volcanic Eruptions over Eurasia and MENA Using the MIROC6 Coupled Climate Model

Tropical volcanic eruptions are significant drivers of climate variability, inducing North Atlantic Oscillation (NAO)-like circulation changes that lead to high-latitude Eurasian winter warming and amplified cooling in the Middle East and North Africa (MENA). However, recent studies have raised concerns about the robustness of this post-eruption NAO-like response, suggesting that its regional impacts on Eurasia and MENA could be linked to coexisting El Niño-like variability rather than volcanic-induced NAO variability. To address this gap, this study utilizes the high-top MIROC6 coupled model to examine the roles of NAO and ENSO in shaping regional climate dynamics over MENA following tropical volcanic events. Our findings reveal that post-eruption winter responses are primarily driven by NAO, with El Niño-like conditions amplifying MENA cooling but not initiating it. In summer, volcanic aerosols weaken the Hadley circulation's updraft branch (i.e., ITCZ), leading to tropical warming and drying, with further amplification by ENSO interactions. These results validate MIROC6's effectiveness in simulating volcanic impacts and offer critical insights for interpreting climate models and informing post-eruption climate policies.