In the GeoMIP project, the G4 experiment proposes an injection in the stratosphere of a certain number of Tg-S/yr in order to offset the warming produced by the increase of well mixed greenhouse gases (WMGHG). The produced thick sulfate aerosol cloud would scatter part of the incoming solar radiation, thus cooling the surface. At the same time, it would warm the lower stratosphere, producing changes in the global circulation, as well as changes in the concentration of radiatively active species such as O3 and CH4. Another possible environmental side effects would be the potential increase of surface deposition of sulfate aerosols. In this study we present results from a climate-chemistry coupled model (ULAQ-CCM) and a chemistry-transport model (GEOS-CHEM), assuming a sustained lower stratospheric tropical injection of 8 Tg-SO2/yr.
As expected from budget estimates, total S-deposition is found to increase by approximately 3% with respect to baseline atmospheric. According to the models, S-deposition changes range from approximately zero over continental Europe to 10% over the Arctic, Oceania and Antarctica, up to 13% over the South Indian ocean.
Daniele Visioni received his Master in Atmospherical Physics in 2015 and is now a PhD student in Atmospherical Physics and Chemistry at University of L’Aquila, in Italy. His primary area of research is Stratosphere-Troposphere interaction and the dynamical and chemical effects of sulfate geoengineering.