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piControl

The piControl configuration simulates the climate prior to the industrial revolution using prescribed CO2 concentrations and atmospheric forcings estimated for the year 1850.

This configuration is used for the CMIP7 piControl experiment.

Info

Please note that the settings described below are implemented in the configuration and no further changes are required to run it. The descriptions below are included to aid in understanding of the configuration and to assist with making modifications.

Inputs

Atmosphere

The following input files provide external forcings for 1850 to the atmosphere model. Each file contains 12 months of data which are repeated each year in the model:

  • OCFF_1850_cmip7.anc: Organic carbon (OC) anthropogenic emissions in kg(C) m-2 s-1.
  • BC_1850_cmip7.anc: Black carbon (BC) anthropogenic emissions in kg(C) m-2 s-1.
  • scycl_1850_cmip7.anc: SO2 anthropogenic emissions, reported in kg(S) m-2 s-1. Split into emissions for low and high model levels. Contains a separate variable for climatological anthropogenic DMS emissions in kg(S) m-2 s-1
  • Bio_1850_cmip7.anc: Fire emissions of OC and BC in kg(C) m-2 s-1. Split into emissions for low and high model levels.
  • biogenic_351sm.N96L38: Climatological mass mixing ratios of biogenic aerosols.
  • sulpc_oxidants_N96_L38: Climatological OH, HO2, H2O2, and Ozone MMRs, used in sulphur cycle chemistry calculations.
  • DMS_conc.N96: Dimethyl sulphide concentration in seawater given in nmol L-1.
  • ozone_1850_cmip7.anc: Zonal mean ozone mass mixing ratio used in atmosphere radiation calculations.

Land

The following input files provide data to the CABLE land surface model:

  • Ndep_1850_cmip7.anc: Nitrogen deposition in g(N) m-2 day-1.

Land surface type mappings for 1850 are derived from the LUH3 dataset and are included directly in the UM restart file.

Restart file

The piControl configuration uses a restart file from the end of the model spin up. This initial restart uses calendar year 101.

Key settings

Values for greenhouse gas concentrations, volcanic forcings, and the solar constant are set in the following atmosphere configuration files. Each value is treated as a global constant in the model.

atmosphere/namelists

 CO2_MMR= 4.3189e-04,
 O2MMR=    0.2314,
 N2OMMR= 4.1256e-07,
 CH4MMR= 4.4228e-07,
 C11MMR= 0.000000e+00,
 C12MMR= 0.000000e+00,
 C113MMR= 0.000000e+00,
 HCFC22MMR= 0.000000e+00,
 HFC125MMR= 0.000000e+00,
 HFC134AMMR= 0.000000e+00,

atmosphere/input_atm.nml

 SC=1361.617
 VOLCTS_val=135.2