New submodel for emissions from Explosive Volcanic ERuptions (EVER v1.1) within the Modular Earth Submodel System (MESSy, version 2.55.1)

This work documents the operation of a new submodel for tracer emissions from Explosive Volcanic ERuptions (EVER v1.1), developed within the Modular Earth Submodel System (MESSy, version 2.55.1). EVER calculates additional tendencies of gaseous and aerosol tracers based on emission source parameters, aligned to specific sequences of volcanic eruptions or other atmospheric emission sources and allowing various vertical emission profiles. We show that volcanic SO$_2$ plumes can be reasonably reproduced through EVER emissions in numerical simulations with the ECHAM/MESSy Atmospheric Chemistry Model (EMAC), using satellite observations of SO$_2$ columns and mixing ratios following the explosive eruption of the Nabro volcano (Eritrea) in 2011 and a degassing event of the Kilauea volcano (2018) in Hawaii. Previous volcanic studies have shown large variability in stratospheric SO$_2$ burdens depending on the chosen volcanic emission databases and parameters. Sensitivity studies on SO$_2$ emissions from the Nabro volcano explore perturbations of the emission source parameters, revealing that emission altitude and the emitted mass above the tropopause are most important for the mid- to long-term evolution of stratospheric SO$_2$ plumes and the resulting stratospheric aerosol, while the correct timing and geographical location of the stratospheric entrance are crucial for the shortterm plume evolution. ... mehrWe integrate information from a volcanic SO$_2$ emission inventory, additional satellite observations, and our findings from the sensitivity studies to establish a historical standard setup for volcanic eruptions impacting stratospheric SO$_2$ from 1990 to 2023. This setup was successfully evaluated with satellite observations of stratospheric SO$_2$ burden and aerosol optical properties. We advocate for this to be a standardized setup in all simulations within the MESSy framework concentrating on the upper troposphere and stratosphere in this period. Further potential
applications of EVER involve studies on volcanic ash, wildfires, solar radiation modification, and atmospheric transport processes.