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Table of Contents
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6ka Experimental Design
Boundary conditions
Summary of 6ka boundary conditions
| PMIP3/CMIP5 | |
|---|---|
| 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 * |
* Sensitivity experiments will be proposed as part of a working group to test the uncertainties due to the remnant ice-sheet. If you are interested to participate to this working group contact Pascale Braconnot
Vegetation
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 are forced by CO2 concentrations. Please use the same protocol as in CMIP5 to store the carbon fluxes and the variables needed for PCMIP (see pcmip Project and CMIP5)
Insolation
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 to compare paleo and PI seasonal cycle
6ka for groups only running PMIP3 experiments
If you only run PMIP3 experiments we recommand that you follow CMIP5 (see taylor_cmip5_dec31.pdf) or PMIP2 (PMIP2 web site) for the PI simulation
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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