Modulating and Resetting Impacts of Different Volcanic Eruptions on North Atlantic SST Variations

This study investigates the impact of volcanic eruption on the North Atlantic (NA) sea surface temperature (SST) during the last millennium based on both model simulations and reconstructions. Our focus is on the two types of relations between the states of SST and associated climate variables before and after the eruption: modulating and resetting. Here, modulating means that the posterior conditions depend on the initial SST and the volcano-induced cooling is linearly superimposed on the initial SST phases, while resetting means that the posterior conditions are independent from the initial condition. Our analysis demonstrates that equatorial and northern volcanic eruptions larger than 30 Tg could reset NA SST, and there is a limitation of SST decrease after eruption, indicating the largest SST decrease does not exceed a certain value. While equatorial volcanic eruptions larger than 100 Tg and northern volcanic eruptions larger than 30 Tg can reset subsurface temperature changes. In contrast, even the largest volcanic eruption during the last millennium cannot reset the Atlantic Meridional Overturning Circulation.