Dataset for manuscript by Byrom, R., Myhre, G., Olivié, D., and Schulz, M.: Investigating the role of stratospheric ozone as a driver of inter-model spread in CO2 effective radiative forcing, Atmospheric Chemistry and Physics, 2025.

Data are orgainsed and curated by Rachael Byrom (rachael.byrom@cicero.oslo.no).

A description of the data in each of the 'NorESM2' and 'PORT' folders is given below. 


NorESM2
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This folder contains output from six atmosphere-only NorESM2-MM simulations that have been used to calculate ERF following an abrupt quadrupling of CO2 relative to pre-industrial (1850) conditions using prescribed SST and sea-ice extent climatologies (see Text S1 in the manuscript supplement for further detail on model configuration). 

These six simulations provide us with output for three ERF experiments, each with a baseline (control) integration and a perturbed (4xCO2) integration. Data from each of the six simualtions are given in the folders listed below:

NF1850frc2norbc.baserun
NF1850frc2norbc.4xCO2

NF1850frc2norbc.O3x1.5.baserun
NF1850frc2norbc.O3x1.5.4xCO2  

NF1850frc2norbc.O3x0.5.baserun
NF1850frc2norbc.O3x0.5.4xCO2      

Data from NF1850frc2norbc.baserun and NF1850frc2norbc.4xCO2 form the 'standard' 4xCO2 ERF estimate calculated using years 6-30 in Section 3 of the manuscript and using years 6-15 in Section 4. 

Data from NF1850frc2norbc.O3x1.5.baserun and NF1850frc2norbc.O3x1.5.4xCO2 form the 'O3x1.5' 4xCO2 ERF estimate where stratospheric ozone concentration has been increased by 50% in the control and perturbed simulations. ERF is calculated using years 6-15 (Section 4). 

Data from NF1850frc2norbc.O3x0.5.baserun and NF1850frc2norbc.O3x0.5.4xCO2 form the 'O3x0.5' 4xCO2 ERF estimate where stratospheric ozone concentration has been decreased by 50% in the control and perturbed simulations. ERF is calculated using years 6-15 (Section 4). 


PORT
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This folder contains output from the PORT (Parallel Offline Radiative Transfer) code. We perform six PORT simulations to calculate IRF following an abrupt quadrupling of CO2 corresponding to the ERF simualtions performed by NorESM2. As above, these six simulations provide output for three IRF experiments, each with a baseline (control) integration and a perturbed (4xCO2) integration. Data from each of the six simualtions are given in the folders listed below:


NF1850frc2norbc.baserun.PORT
NF1850frc2norbc.4xCO2.PORT	

NF1850frc2norbc.O3x1.5.baserun.PORT
NF1850frc2norbc.O3x1.5.4xCO2.PORT	

NF1850frc2norbc.O3x0.5.baserun.PORT	
NF1850frc2norbc.O3x0.5.4xCO2.PORT  

Data from NF1850frc2norbc.baserun.PORT and NF1850frc2norbc.4xCO2.PORT form the 'standard' 4xCO2 IRF estimate and is calculated using the first twelve months of output.

Data from NF1850frc2norbc.O3x1.5.baserun.PORT and NF1850frc2norbc.O3x1.5.4xCO2.PORT form the 'O3x1.5' 4xCO2 IRF estimate where stratospheric ozone concentration has been increased by 50% in the control and perturbed simulations. IRF is calculated using the first twelve months of output.

Data from NF1850frc2norbc.O3x0.5.baserun.PORT and NF1850frc2norbc.O3xo.5.4xCO2.PORT form the 'O3x0.5' 4xCO2 IRF estimate where stratospheric ozone concentration has been decreased by 50% in the control and perturbed simulations. IRF is calculated using the first twelve months of output.


Note that in both the 'NorESM2' and 'PORT' sub-folders, H0 files include the standard model output of variables whilst H1 files provide additional radiation diagnostics.