Effects of solid particle SAI on tropospheric climate and the ocean

Stratospheric aerosol injection (SAI) commonly utilizes sulfur as an injection material. Sulfur scatters solar radiation while also absorbing it, causing warming in the lower stratosphere, particularly in tropical regions.This results in a modified equator-to-pole temperature gradient and stratosphere-troposphere interactions, leading unwanted side effects such as a warming over Eurasia and a decrease of the sea-ice cover. One approach to lessen the side effects is to use different types of materials. The use of solid particles as an injection material diminishes the equator-to-pole gradient due to their lower radiative absorption. Consequently, the side effects are significantly less pronounced with solid particle SAI compared to sulfur-based SAI.Findings from various 20th-century simulations with a fully coupled chemistry global climate model will be presented, utilizing sulfur and solid particles such as alumina, calcite, and diamonds. The emphasis will be on surface and oceanic changes. In SAI simulations, changes in the Atlantic Meridional Overturning Circulation (AMOC), sea-ice extent, and oceanic temperature and salinity show considerable reduction compared to scenarios without SAI. Additionally, the influences of different SAI materials on the hydrological cycle and the radiation budget will be discussed.