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Table of Contents
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6ka Experimental Design
Boundary conditions
Summary of 6ka boundary conditions
| PMIP3 | Alternative solution | |
|---|---|---|
| Orbital parameters | ecc=0.018682, obl=24.105 °, peri-180°= 0.87 ° | |
| date of the Vernal equinox | March 21 at Noon | |
| Trace Gazes | CO2 = 280 ppm, CH4 = 650 ppb, N2O = 270 ppb, CFC = 0, O3 = same as PI | |
| Aerosols | Same as PI | |
| Solar constant | 1365W/m2 | As in PI |
| Vegetation | Interactive | See specific note below |
| Ice sheet | remnant Laurentide ice-sheet (provided) | Same as PI |
| Topography and coastline | Modification of the Hudson Bay (provided) | Same as PI |
Vegetation
Depending on the complexity of the model used the vegetation will be either
- computed by the model
- prescribed to PI
- prescribed to 6ka vegetation reconstructed from a combination of model output and data analyses (please use the map provided here)
- Obtained from asynschonous coupling with a DVGM (Biome 4 model provided )
For Earth System Model with interactive carbone cycle The simlations are force by the CO2 concentrations. Please use the same protocal as in CMIP5 to store the carbone fluxes and the variables needed for PCMIP (see list here)
Insolation Note that insolation should follows PMIP requirements. Please check it carefuly using the following tables
Initial conditions
| PMIP3 | Alternative solution | |
|---|---|---|
| Initial conditions | branch off PI after adjustement | Same as in PI |
| Model spin up | Same as in PI |
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Discussion
For orbital parameters, include how to set orbital year for those models that have that option.
Another alternative solution for modification of Hudson Bay coastlines might be to allow users to specify some percentage of appropriate land grid squares as lakes.
A vegetation map for 6ka reconstructed from a combination of model output and data analyses would be very useful for modeling groups that will not be using interactive vegetation in their PI and 20th century runs. We could query groups on the best format. For CCSM, a pft vegetation map would be best.
For solar constant, do we want to specify under the PMIP3/CMIP5 “prescribed as in CMIP5 PI”?
CMIP5 CO2 pre-industrial concentrations are 285 ppmv for 1850, 286 ppmv for 1860. HadGEM2ES PI control is getting spun up to 286 ppmv, so I would plan on using 286 for the 6k too.