Volcanic modulation of Beryllium-10 atmospheric transport

Cosmogenic ¹⁰Be isotope is an important proxy for past solar activity that can be measured from natural archives such as ice cores. It is mostly produced in the stratosphere and its atmospheric lifetime until the deposition to the surface depends on different transport processes. In the troposphere, ¹⁰Be deposition to natural archives occurs comparatively quickly, being dominated by scavenging, with weather patterns causing regional variations. The stratospheric and cross-tropopause transport of the isotopes is affected by their attachment to the stratospheric aerosol particles, presenting an additional effect of size-dependent gravitational sedimentation.  Strong volcanic eruptions massively increase the stratospheric aerosol loading, thus increasing its effect on the ¹⁰Be transport and deposition, which has been proposed as a major complication term in the interpretation of proxy records. In our study, we address this effect by employing the state-of-the-art aerosol-chemistry-climate model SOCOL-AERv2-Be that has a full ¹⁰Be atmospheric cycle, including its attachment to aerosol particles. We isolate the effects of sedimentation by comparing simulations with and without it for the ¹⁰Be tracer. In these simulations we examine the long-term climatological effects of a background aerosol layer on the ¹⁰Be distribution in the atmosphere and the resulting deposition maps. In another set of simulations we specifically focus on the influence of the enhanced stratospheric aerosol layer after volcanic events of various magnitudes, including their large-scale dynamical effects on the ¹⁰Be transport induced by the lower stratospheric heating. The results are compared with ice core data from the Greenland and Antarctic stations.