Author's Tracked Changes.pdf

Volcanic eruptions increase stratospheric water vapor (SWV) through long-wave heating by aerosols, altering the atmospheric energy budget. Researchers analyzed tropical volcanic eruptions with sulfur injections ranging from 2.5 to 40 TgS using the Max Planck Institute's Earth System Model. Significant SWV increases were found, ranging from 5 to 160%, with the mean increase over all ensemble members from 2.5 TgS onward. However, the standard deviation between control run members was larger than the SWV increase for single ensemble members for eruption strengths up to 20 TgS. A historical simulation of the Mt. Pinatubo eruption showed SWV increases slightly higher than the 10 TgS simulation due to differences in aerosol profile shape. The additional tropical clear-sky SWV forcing for different eruption strengths ranged from 0.02 to 0.65 W/m², accounting for 2.5 to 4% of the aerosol radiative forcing in the 10 TgS scenario. The monthly cold point temperature increase allowed for an estimation of SWV increases, with a 12% increase per Kelvin increase in mean cold point temperature.