HiLLA-SAI simulations in UKESM1, CESM2-WACCM and E3SMv3

Simulations of High-latitude low-altitude (HiLLA) stratopsheric aerosol injection (SAI) under various injection strategies, carried out in three earth system models: UKESM1, CESM2-WACCM, and E3SMv3. The simulations are in support of the analysis contained in Duffey et al., 2025; The global climate response to High-Latitude Low-Altitude Stratospheric Aerosol Injection (HiLLA-SAI) (forthcoming). In each case, 12Tg SO2 per year is injected into the lower stratosphere, starting in 2035, and causing the climate state to deviate from the background SSP2-4.5 scenario. Two central injection strategies are simulated: HiLLA-13 and HiLLA-15, which have injection at 60°N/S in the local spring (March-June/September-Devember), and at 13 km and 15 km, respectively. These simulatations are 35-years in length. Nine additional 3-year sensitivy simulations vary the injection latitude, longitude, altitude and seasonality. See also the analysis code here https://github.com/alistairduffey/HiLLA_MM Data here does not include outpus on levels (ozone, geopotential height and SO4 burdens), as these files are too large for practical storage on Zenodo. These are available either on the UK's CEDA archive or AWS via the Reflective Cloud, contact Alistair Duffey ([e-mail]) for help locating them.