GeoMIP G6-1.5K REMAP aerosols - CESM2-WACCM to NorESM

This dataset provides prescribed stratospheric aerosol optical properties for the NorESM2-LM climate model, derived from twelve input CESM2-WACCM6 simulations of stratospheric aerosol injection (SAI). 

Input scenarios, see Visioni et al., (2026; 2024): 

• G6-1.5K-SAI (30°N/S injection at 21km altitude, to hold global temperature at its 2020-2039 value, around 1.5K above pre-industrial, under background SSP2-4.5 warming, over 2035-2084)
• G6-1.5K-SAI-End (termination of G6-1.5K-SAI in 2085)
• G6-1.5K-HiLLA (High-latitude low-altitude scenario: 60°N/S injection at 15km altitude, to hold global temperature at its 2020-2039 value, around 1.5K above pre-industrial, under background SSP2-4.5 warming, over 2035-2084)
• Nine single latitude constant injection magnitude scenarios, each injecting 12 terragrams SO2 per year. These are labelled by their latitude of injection and season ('ANN' for annually constant; 'MAM' for constant innjection over only northern hemipshere spring, March-April-May; 'SON' for southern hemisphere spring, September-October-November; see Zhang et al., 2024)

The G6-1.5K-SAI, -HiLLA and single latitude injeciton scenarios were run by Walker Lee, NCAR. The termination scenario, G6-1.5K-SAI-End was run by Claire Zarakas at Carbon Plan.

Each scenario has three associated output netCDF files stored here. These are (for the G6-1.5K-SAI scenario):

• geomip_WACCM_G6-1p5K-SAI_to_NorESM2-LM_sun.nc : monthly zonal-mean extinction, single-scattering albedo and asymmetry factor on the 14 short-wave NorESM2-LM radiation bands;  
• geomip_WACCM_G6-1p5K-SAI_to_NorESM2-LM_earth.nc : monthly zonal-mean extinction, single-scattering albedo and asymmetry factor on the 16 long-wave NorESM2-LM radiation bands; 
• geomip_WACCM_G6-1p5K-SAI_to_NorESM2-LM_p.nc : pressure, surface area density and mean radius.

The optical properties were computed with the REMAP Mie code (Jorimann et al., 2025), from WACCM’s aerosol number, size, temperature and humidity.

The code base as used to calculate these outputs is available here: https://github.com/alistairduffey/REMAP_GeoMIP/tree/NorESM_testing