Winter Warming in Northern Eurasia Following the 1783 Laki Volcanic Eruption

        Northern Eurasian winter warming (NEWW) is reported both in the observation and reconstruction following major tropical volcanic eruptions. However, current climate models struggle to accurately simulate this warming phenomenon, posing challenges to fully understand and validate this distinct climate response amidst the general trend of volcano-induced global cooling. Here we show that, the persistent volcanic cloud from summer to late autumn and the associated warming of the mid-latitude stratosphere plays a pivotal role in triggering NEWW. The role of winter aerosols is demonstrated by sensitivity simulations with updated volcanic forcing of the 1783 Icelandic Laki eruption, supported by two recently available temperature reconstructions, and reversely verified by model results of various eruptions without substantial cold season aerosol loadings. The abnormal mid-latitude stratospheric warming enhances the meridional temperature gradient, strengthens the polar vortex, alters both horizontal and vertical energy redistribution that contributed to NEWW. The findings help to reconcile the model-observation discrepancy of post-eruption winter climate responses, and point to the critical role of stratosphere-troposphere coupling in responding and redistributing the radiative perturbation.