Impact of Stratospheric Aerosol Injection on the East Asian Winter Monsoon

Abstract

Stratospheric aerosol injection (SAI) has been proposed as a potential measure to alleviate global warming; however, uncertainties exist in its regional climate impacts. This study investigates the influence of the SAI on the East Asian winter monsoon (EAWM) by analyzing the G6sulfur simulation from the Geoengineering Model Intercomparison Project. Our results show that the SAI intensifies the Siberian high and Aleutian low, enhances the low-level northerly winds along the coast of East Asia and deepens the East Asian trough during 2080–2099, reversing the weakening of EAWM in high-emission Shared Socioeconomic Pathway scenario (SSP5-8.5). Comparison between the G6sulfur and SSP5-8.5 simulations indicates that, the SAI-induced strong cooling in the central equatorial Pacific excites a poleward-propagating Rossby wave train and strengthen the EAWM. Meanwhile, the negative vorticity advection in the middle troposphere and the radiative cooling over the Siberian high region caused by SAI also intensify the EAWM.