Changes in Hadley circulation and intertropical convergence zone under strategic stratospheric aerosol geoengineering

Abstract Stratospheric aerosol geoengineering has been proposed as a potential solution to reduce climate change and its impacts. Here, we explore the responses of Hadley circulation (HC) intensity intertropical convergence zone (ITCZ) using strategic stratospheric geoengineering, in which sulfur dioxide was injected into stratosphere at four different locations maintain global-mean surface temperature interhemispheric equator-to-pole gradients present-day values (baseline). Simulations show that, relative baseline, generally maintains northern winter December–January–February (DJF) HC under RCP8.5, while it overcompensates for greenhouse gas (GHG)-forced southern June–July–August (JJA) increase, producing 3.5 ± 0.4% weakening. The residual JJA is mainly associated with heating tropospheric response due enhanced concentrations. Geoengineering GHG-driven northward ITCZ shifts, 0.7° 0.1° 0.2° latitude southward migrations DJF, respectively baseline. These are affected by tropical differences both free troposphere. Further strategies reducing shifts could involve minimizing restoring preserving differences.