Input data set: Atmospheric composition (ISIMIP4b)

The atmospheric greenhouse gas concentration dataset provides prescribed atmospheric CO₂ and CH₄ concentrations for ISIMIP4b impact simulations. The dataset is based on the CMIP7 Input4MIPs greenhouse gas concentration products and supports both concentration-driven and emission-driven simulations. They are Identifiable by the “esm-” prefix as well.

The dataset contains atmospheric greenhouse gas mole fractions expressed as dry-air mixing ratios. It includes both CO₂ (ppm) and CH₄ (ppb) concentration time series at annual and monthly temporal resolution.

For concentration-driven simulations, the prescribed concentration time series are taken directly from the CMIP7 Input4MIPs greenhouse gas concentration datasets for the historical period and the corresponding future scenarios.

For emission-driven simulations, atmospheric CO₂ and CH₄ concentrations are diagnosed by the participating Earth System Models and extracted from the CMIP7 simulations. These model-specific concentration time series are provided to ensure consistency between emission-driven climate simulations and ISIMIP impact simulations.

The greenhouse gas concentration data are derived from the CMIP7 Input4MIPs greenhouse gas concentration products:

Historical: CR-CMIP-1-0-0
Very low forcing scenarios: CR-vl-1-1-0
High forcing scenarios: CR-h-1-1-0

For concentration-driven simulations, these datasets provide the prescribed annual and monthly atmospheric CO₂ and CH₄ concentration time series. For emission-driven simulations, the corresponding annual and monthly concentrations diagnosed by the participating CMIP7 Earth System Models are extracted from the model output and distributed as model-specific forcing datasets for ISIMIP4b.

For ISIMIP participants, these files are available for download on the DKRZ server:
/work/bb0820/ISIMIP/ISIMIP4b/InputData/climate/atmosphere_composition/