====== Design for the LGM run======

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You will find on this page information about the experiment design for the PMIP4 [[.:lgm|Last Glacial Maximum]] experiment.

Please make sure to read the [[#Associated_publications|Associated publications]] before setting up your experiments or using the output data, and read any //how-to// sections associated with specific boundary conditions.

Get in touch with the following people if you have questions:


| [[Masa.Kageyama@lsce.ipsl.fr|Masa Kageyama]] | Scientific questions |
| [[Jean-Yves.Peterschmitt@lsce.ipsl.fr|Jean-Yves Peterschmitt]] | Technical questions or missing data|
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===== Associated publication =====

**The PMIP4 contribution to CMIP6 – Part 4: Scientific objectives and experimental design of the PMIP4-CMIP6 Last Glacial Maximum experiments and PMIP4 sensitivity experiments**, Kageyama, M., Albani, S., Braconnot, P., Harrison, S. P., Hopcroft, P. O., Ivanovic, R. F., Lambert, F., Marti, O., Peltier, W. R., Peterschmitt, J.-Y., Roche, D. M., Tarasov, L., Zhang, X., Brady, E. C., Haywood, A. M., LeGrande, A. N., Lunt, D. J., Mahowald, N. M., Mikolajewicz, U., Nisancioglu, K. H., Otto-Bliesner, B. L., Renssen, H., Tomas, R. A., Zhang, Q., Abe-Ouchi, A., Bartlein, P. J., Cao, J., Li, Q., Lohmann, G., Ohgaito, R., Shi, X., Volodin, E., Yoshida, K., Zhang, X., and Zheng, W., Geosci. Model Dev., 10, 4035-4055, [[https://doi.org/10.5194/gmd-10-4035-2017|doi:10.5194/gmd-10-4035-2017]], 2017.\\ \\ [[https://www.geosci-model-dev.net/10/4035/2017/gmd-10-4035-2017-supplement.zip|Supplement (Kageyama et al, GMD, 2017)]]

[ [[#supplementary_material|Supplementary material]] ]

===== Specifications =====


^      ^PMIP4-CMIP6 specifications ^ 
| PMIP4-CMIP6 name | <wrap em>lgm</wrap> |
| Astronomical parameters  | **eccentricity** = 0.018994 \\ **obliquity** = 22.949° \\  **perihelion-180°** = 114.42°  \\  **Date of vernal equinox**  :  March 21 at noon  |  
| Trace gases  | **CO<sub>2</sub>** = 190 ppm \\ **CH<sub>4</sub>** = 375 ppb \\ **N<sub>2</sub>O** = 200 ppb \\ **CFC** = 0 \\ **O<sub>3</sub>** = same as in CMIP6 piControl  | 
| Solar activity | Same as in CMIP6 piControl  | 
| Ice sheets      | Modified\\ [[:data:ice|Access to data]] | 
| Topography and coastlines  | Modified\\ [[:data:ice|Access to data]] | 
| Volcanic activity | Same as in CMIP6 piControl  |
| Aerosols  | Modified sources, atmospheric concentrations or radiative forcing, depending on model complexity and model configuration used for DECK and historical experiments \\  cf. documenting papers: Kageyama et al, in prep and Kageyama et al, subm. \\ [[:data:aerosols|Access to data]]| 
| Vegetation     | Depending on model complexity and model configuration used for DECK and historical experiments: \\ Interactive vegetation **or** Interactive carbon cycle (LAI) **or** Prescribed to present-day values or mid-Holocene values computed from off-line vegetation model \\ The methodology to represent vegetation should be the same as for the CMIP6 piControl simulation  \\  cf. documenting papers: Kageyama et al, in prep and Kageyama et al, subm. |

===== Supplementary material =====

The scripts used for generating the LGM boundary conditions for the IPSL model, following the steps detailed in the //Kageyama et al// paper, can be dowloaded from [[https://sharebox.lsce.ipsl.fr/index.php/s/3HAAlA36MoZrAvm|LSCE]]. Get in touch with [[pmip4web@lsce.ipsl.fr|Jean-Yves Peterschmitt]] if you need to access this material.