TIER1 CCSM4 Mid-Holocene

AR5 Case Specifications

(Taken directly from

Summary of 6ka boundary conditions
Orbital parameters:
	[ ecc = 0.018682 ] 
	[ obl = 24.105 ] 
	[ peri-180 = 0.87 ]

Date of vernal equinox: 	March 21 at noon
Trace gases:
	[ CO2 = 280 ppm ] 
	[ CH4 = 650 ppb ] 
	[ N2O = 270 ppb ] 
	[ CFC = 0 ] 
	[ O3 = same as in CMIP5 PI ]
Aerosols: 	Same as in CMIP5 PI
Solar constant: 	Same as in CMIP5 PI
Vegetation: 	prescribed or interactive as in CMIP5 PI
Ice sheets: 	Same as in CMIP5 PI *
Topography and coastlines: 	Same as in CMIP5 PI * 


The vegetation should be treated as in the CMIP5 PI experiment. The reason is
that in CMIP5 we test the version of the model used for future climate
projections. Since OA and ESM models will be considered, depending on the
model used the vegetation will be

      prescribed to PI (which means both vegetation types and LAI are
prescribed )
      Prescribed to PI with interactive LAI (models with interactive carbone
cycle, but no vegetation dynamics)
      Computed by the model (models with dynamic vegetation)

A 6ka reconstructed vegetation map from a combination of model outputs and
data analyses will be provided for sensitivity experiments. If you are
interested please contact Bette Otto-Bliesner, Sandy Harrison and Pat Bartlein
who will lead the corresponding working group.
For Earth System Models with interactive carbon cycle

The simulations should be forced by the prescribed 6ka CO2 concentrations.
Please use the same protocol as in CMIP5 to store the diagnostic carbon fluxes
and the variables needed for PCMIP (see pcmip Project and CMIP5)

Note that insolation should follows PMIP requirements. Please check it
carefully using the following tables (6ka BP insolation tables)

Check carefully the date of the Vernal equinox, because it has implications
when we compare paleo and PI seasonal cycle