High-resolution analyses of ice cores from Antarctica and Greenland reveal an explosive volcanic eruption in the tropics in A.D. 1809 which is not reflected in the historical record. A comparison in the same ice cores of the sulfate flux from the A.D. 1809 eruption to that from the Tambora eruption (A.D. 1815) indicates a near-equatorial location and a magnitude roughly half that of Tambora. Th...

A vortex close to a no-slip wall gives rise to the creation of new vorticity at the wall. This vorticity may organize itself into vortices that erupt from the separated boundary layer. We study how the eruption process in terms of the streamline topology is initiated and varies in dependence of the Reynolds number Re. We show that vortex structures are created in the boundary layer for Re aroun...

Entrainment of air by turbulent mixing plays a central role in the dynamics of eruption clouds; the amount of entrained air controls eruption styles and heights of eruption columns. The efficiency of entrainment is quantified by the entrainment coefficient: the ratio between mean inward radial velocity at the edge and the mean vertical velocity. We directly determined the entrainment coefficien...