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Pre-Industrial Control Run Experimental Design

This was a BC development page (see discussion panel at the end of the page)

Make sure you use the final version of the PI BC!

Boundary conditions

PI for PMIP3/CMIP5 experiments

The Preindustrial control should be the same as the one used for CMIP5 experiments. It is thus the same reference as the one for 20th century simulations and future climate projections (see taylor_cmip5_dec31.pdf).

PI for groups only running PMIP3 experiments

Summary of PI boundary conditions

PMIP3 Alternative solution
Orbital parameters [ ecc = 0.016724 ] - [ obl = 23.446° ] - [ peri-180° = 102.04° ]
Date of vernal equinox March 21 at noon
Trace gases [ CO2 = 280 ppm ] - [ CH4 = 760 ppb ] - [ N2O = 270 ppb ] - [ CFC = 0 ] - [ O3 = Modern - 10 DU ]
Aerosols Same as PI
Solar constant 1365 W/m2 As in PI
Vegetation Interactive See specific note below
Ice sheets Present day
Topography and coastline Present day

Please use the discussion panel to comment this table!


Depending on the complexity of the model used the vegetation will be either:

  • computed by the model
  • prescribed to PI (some ESMs may also only compute vegetation phenology and carbon cycle).

Land use

Land use should be included in the PI vegetation map. In that case, care should be taken that the land use map used in the PI simulation is consistent with the one used for land use evolution either for the 20th century or the last Millennium.

For Earth System Models with interactive carbon cycle

The simulations are forced by the CO2 concentrations. Please use the same protocol as in CMIP5 to store the carbon fluxes and the variables needed for PCMIP (see list here External Link)


Note that insolation should follow PMIP requirements. Please check it carefully using the following tables (PI insolation tables)

Initial conditions

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Gavin Schmidt, 2009/02/10 21:02

Since PMIP won't be able to regulate the insolation that people use in the 20C3M runs and the standard controls, and some people will be varying insolation in the LM runs, more guidance is required here. Maybe, we should specify 1850AD conditions?

Pascale Braconnot, 2009/02/12 17:11

Then what is the value you recommend in that case / the 1365W/m2 required in PMIP, which is already different from the 1367 a lot of group have in practive in their code? For the orbital parameters I can look at it. But I am not sure we will be able to do something. The real pb is what will be the PI for the Millenium simulations ? It should be year 850, but then how do we connect this with the preindustrial (1860 usually run for CMIP?). Also PMIP gaz etc… was rather 1750 than 1860. I see similar pb with the landuse map.

PMIP3 Guest Login,, 2009/02/21 18:57

For the PI for groups only running PMIP3 experiments, we should define both an orbital year and the associated orbital parameters. It would be useful to query the CMIP5 modeling groups to determine what orbital definition will be used in their controls and 20C3M runs. The PMIP3 trace gases could also be set at 1850AD values to make these runs most consistent with the CMIP5 model runs.

John Hughes, Met Office Hadley Centre, 2009/11/24 14:19

Hi, CMIP5 CO2 concentrations for pre-industrial are 286 ppmv for 1860 and 285 ppmv for 1850 rather than 280.

pmip3/design/pi/index.txt · Last modified: 2010/09/16 12:35 by jypeter