Experiments

Detection and attribution (D&A) studies typically require unforced control simulations and historical simulations including all major anthropogenic and natural forcings.  Such simulations will be carried out as part of the CMIP6 DECK and the CMIP6 historical simulation.  In addition D&A studies require simulations covering the historical period driven by individual forcings or subsets of forcings only:  these will be undertaken as part of DAMIP.  Key novel features of the DAMIP experimental design following D&A-relevant simulations in CMIP5 are:
  • new historical simulations of aerosols-only, stratospheric-ozone-only, CO2-only, solar-only, and volcanic-only forcing, facilitating an improved estimation of the climate response to individual forcing;
  • future single forcing experiments, allowing observationally-constrained projections of future climate change;
  • an experimental design which allows models with and without coupled atmospheric chemistry to be compared on an equal footing.

Tier 1 experiments
Name of experiment
Description
(forcing agents perturbed)
Period
CMIP6 historical simulations and ScenarioMIP SSP2-4.5
Enlarging ensemble size of the CMIP6 historical simulations (1850–2014) and the SSP2-4.5 simulations of ScenarioMIP (2015–2020). (As historical: WMGHGs, BC, OC, SO2, SO4, NOx, NH3, CO, NMVOC, nitrogen deposition, ozone, stratospheric aerosols, solar irradiance, land use).
 1850-2020
hist-nat Natural-only historical simulations (solar irradiance, stratospheric aerosol)
 1850-2020
hist-GHG Well-mixed greenhouse-gas-only historical simulations (WMGHGs)
 1850-2020
hist-aer
Anthropogenic-aerosol-only historical simulations (BC, OC, SO2, SO4, NOx, NH3, CO, NMVOC)
 1850-2020

Tier 2 experiments
Name of experiment Description
(forcing agents perturbed)
Period
ssp245-GHG Extension of at least one hist-GHG simulation through the 21st century using the SSP2-4.5 greenhouse gas concentrations (WMGHGs)
2021-2100
hist-stratO3
Stratospheric-ozone-only historical simulations (stratospheric ozone)
1850-2020
ssp245-stratO3 Extension of at least one hist-stratO3 simulation through the 21st century using SSP2-4.5 stratospheric ozone concentrations (stratospheric ozone)
2021-2100

Tier 3 experiments
Name of experiment Description
(forcing agents perturbed)
Period
hist-sol
Solar-only historical simulations (solar irradiance)
1850-2020
hist-volc
Volcanic-only historical simulations (stratospheric aerosol)
1850-2020
hist-CO2
CO2-only historical simulations (CO2)
1850-2020
ssp245-aer
Extension of at least one hist-aer simulation through the 21st century using SSP2-4.5 tropospheric aerosol concentrations/emissions (BC, OC, SO2, SO4, NOx, NH3, CO, NMVOC)
2021-2100
ssp245-nat
Extension of at least one hist-nat simulation through the 21st century using SSP2-4.5 solar and volcanic forcing (solar irradiance, stratospheric aerosol)
2021-2100
hist-all-aer2
historical with alternate estimates of anthropogenic aerosol emissions/concentrations (As historical: WMGHGs, BC, OC, SO2, SO4, NOx, NH3, CO, NMVOC, nitrogen deposition, ozone, stratospheric aerosols, solar irradiance, land use)
1850-2020
hist-all-nat2
historical with alternate estimates of solar and volcanic forcing (as historical:
WMGHGs, BC, OC, SO2, SO4, NOx, NH3, CO, NMVOC, nitrogen deposition, ozone, stratospheric aerosols, solar irradiance, land use)
1850-2020