pmip3:design:21k:final
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pmip3:design:21k:final [2010/03/26 14:14] jypeter |
pmip3:design:21k:final [2010/04/02 09:19] jypeter Added 'Links' section |
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| Note that insolation should follows PMIP requirements. Please check it carefuly using the following tables ([[http://pmip2.lsce.ipsl.fr/design/tables/inso_tables_21k.shtml|LGM insolation tables]]). | Note that insolation should follows PMIP requirements. Please check it carefuly using the following tables ([[http://pmip2.lsce.ipsl.fr/design/tables/inso_tables_21k.shtml|LGM insolation tables]]). | ||
| - | Check carefully the date of the Vernal equinox, because it has implications when comparing the paleo and PI seasonal cycles. | + | Check carefully the date of the Vernal equinox, because it has implications when we compare the paleo and PI seasonal cycles. |
| ==== Ice-sheets and related changes ==== | ==== Ice-sheets and related changes ==== | ||
| - | The ice sheet provided for PMIP3/CMIP5 LGM experiments is a blended product obtained by averaging three different ice sheets: ICE-6G v2.0 provided by Dick Peltier, MOCA provided by Lev Tarasov and ANU provided by Kurt Lambeck. More information about this is available in the [[pmip3:design:pi:final:icesheet|LGM ice-sheets description]] page. | + | The ice sheet provided for PMIP3/CMIP5 LGM experiments is a blended product obtained by averaging three different ice sheets reconstructions: ICE-6G v2.0 provided by Dick Peltier, MOCA provided by Lev Tarasov and ANU provided by Kurt Lambeck. More information about this is available in the [[pmip3:design:pi:final:icesheet|LGM ice-sheets description]] page. |
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| Data files are available on the [[pmip3:design:download#pmip3-cmip5_files_for_boundary_conditions|Files for PMIP3 experiments]] page. | Data files are available on the [[pmip3:design:download#pmip3-cmip5_files_for_boundary_conditions|Files for PMIP3 experiments]] page. | ||
| - | Implementing the LGM **ice-sheets** implies changing also the **land-sea mask**, the **land surface elevation** and the **ocean bathymetry** as described below. | + | Implementing the LGM **ice-sheets** implies changing the **land-sea mask**, the **land surface elevation** and the **ocean bathymetry** as described below. Groups having doubts about their setup should contact [[Masa.Kageyama@lsce.ipsl.fr|Masa Kageyama]] and [[pmip2db@lsce.ipsl.fr|Jean-Yves Peterschmitt]]. |
| === Land-sea mask === | === Land-sea mask === | ||
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| If this proves difficult for a modelling group, the **__minimum__** implementation is to: | If this proves difficult for a modelling group, the **__minimum__** implementation is to: | ||
| * fill in the Hudson Bay and the Barents sea, which were covered by the main northern hemisphere ice-sheets. | * fill in the Hudson Bay and the Barents sea, which were covered by the main northern hemisphere ice-sheets. | ||
| - | * close the Bering Strait (by changing the land-sea mask or imposing zero flux on water and sea-ice across the Bering Strait). | + | * close the Bering Strait (by changing the land-sea mask locally or imposing zero flux on water and sea-ice across the Bering Strait). |
| * make sure that the ocean model configuration keeps the following straits open: | * make sure that the ocean model configuration keeps the following straits open: | ||
| - | * Denmark Strait (between Greenland and Ireland). | + | * Denmark Strait (between Greenland and Iceland). |
| * Gibraltar Strait. | * Gibraltar Strait. | ||
| - | * //Indonesia Strait// (//check exact name with Olivier Marti//?). | + | * Indonesian Throughflow (ITF). |
| === Land surface elevation === | === Land surface elevation === | ||
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| === Ice-sheet extent === | === Ice-sheet extent === | ||
| - | The ice-sheet extent (aka //land-sea mask//) should be prescribed using the data provided in [[target.nc|file.nc]], where the ''sftgif'' variable is 0 (%) where there is no ice-sheet, or 100 (%).\\ This mask includes **ice shelves**, which should be included in models that allow this feature. | + | The ice-sheet extent should be prescribed using the data provided in [[target.nc|file.nc]], where the ''sftgif'' variable is 0 (%) where there is no ice-sheet, or 100 (%).\\ This mask includes **ice shelves**, which should be included in models that allow this feature. |
| * The ice shelves can be defined from the ''sftgif'' and ''sftlf'' variables as areas where:\\ ''sftgif'' == 100 **and** ''sftlf'' == 0 | * The ice shelves can be defined from the ''sftgif'' and ''sftlf'' variables as areas where:\\ ''sftgif'' == 100 **and** ''sftlf'' == 0 | ||
| * Groups implementing the provided ice shelves should keep the Greenland-Iceland ridge open in the ocean configuration. | * Groups implementing the provided ice shelves should keep the Greenland-Iceland ridge open in the ocean configuration. | ||
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| The river pathways and basins should be at least adjusted so that fresh water is conserved at the Earth's surface: care should be taken that rivers reach the ocean (due to the lower sea level at LGM, some river mouths have to be displaced towards the coast). | The river pathways and basins should be at least adjusted so that fresh water is conserved at the Earth's surface: care should be taken that rivers reach the ocean (due to the lower sea level at LGM, some river mouths have to be displaced towards the coast). | ||
| - | You can use the river routing provided by Lev Tarasov to change the routing scheme in your code, so that the river pathways is consistent with the presence of the ice-sheet. | + | You can use the river routing provided by Lev Tarasov to change the routing scheme in your code, so that the river pathways is consistent with the presence of the ice-sheet. Please note that to our knowledge, so far, no group has attempted to introduce these changes in river runoff in their model configuration. We would appreciate some feedback from groups who who choose to use this data. |
| \\ Data files are available on the [[pmip3:design:download#pmip3-cmip5_files_for_boundary_conditions|Files for PMIP3 experiments]] page. | \\ Data files are available on the [[pmip3:design:download#pmip3-cmip5_files_for_boundary_conditions|Files for PMIP3 experiments]] page. | ||
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| ==== Ice-sheet mass balance ==== | ==== Ice-sheet mass balance ==== | ||
| - | It is advised to ensure a closed fresh water balance at the Earth's surface: snow accumulating on the ice-sheets should be redistributed to the oceans, either globally or in the adjacent oceans (see PMIP2 recommendation [[http://pmip2.lsce.ipsl.fr|mass balance recommendation]]). | + | It is advised to ensure a closed fresh water balance at the Earth's surface: snow accumulating on the ice-sheets should be redistributed to the oceans, either globally or in the adjacent oceans. |
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| ===== Initial conditions ===== | ===== Initial conditions ===== | ||
| - | |||
| - | * Mean ocean salinity: add +1 PSU everywhere once, at the beginning of the simulation. | ||
| * The surface pressure field must be adjusted to the change in surface elevation over the continents. This can be done: | * The surface pressure field must be adjusted to the change in surface elevation over the continents. This can be done: | ||
| * either by gradually changing the surface elevation in order to avoid generating gravity waves, | * either by gradually changing the surface elevation in order to avoid generating gravity waves, | ||
| * or by adjusting the initial pressure field to the LGM surface elevation.\\ In this case, you must be careful to conserve atmospheric mass. | * or by adjusting the initial pressure field to the LGM surface elevation.\\ In this case, you must be careful to conserve atmospheric mass. | ||
| + | |||
| + | * Mean ocean salinity: add +1 PSU everywhere once, at the beginning of the simulation. | ||
| * The spin up procedure is up to each group, following CMIP5 approach or from a previous cold state. | * The spin up procedure is up to each group, following CMIP5 approach or from a previous cold state. | ||
| - | * Note several groups share the same ocean models for which an initial state can be provided from PMIP2 experiments.\\ If you need an initial state from another group, you can get in touch with [[Olivier.marti@lsce.ipsl.fr]]. | + | * Note several groups share the same ocean models for which an initial state can be provided from PMIP2 experiments.\\ If you need an initial state from another group, you can get in touch with [[Olivier.marti@lsce.ipsl.fr|Olivier Marti]] and [[pmip2db@lsce.ipsl.fr|Jean-Yves Peterschmitt]]. |
| + | |||
| + | * Groups with high resolution model for which it is too difficult to run long simulations should contact [[Olivier.marti@lsce.ipsl.fr|Olivier Marti]] and [[pmip2db@lsce.ipsl.fr|Jean-Yves Peterschmitt]] to find the best alternative solution. | ||
| + | |||
| + | ===== Links ===== | ||
| + | |||
| + | * PCMIP Project (**P**alaeo**C**arbon **M**odelling **I**ntercomparison **P**roject)\\ http://www.bridge.bris.ac.uk/projects/pcmip | ||
| - | * Groups with high resolution model for which it is too difficult to run long simulations should contact [[Olivier.marti@lsce.ipsl.fr]] to find the best alternative solution. | + | * CMIP5 (**C**oupled **M**odel **I**ntercomparison **P**roject Phase **5**)\\ http://cmip-pcmdi.llnl.gov/cmip5/ |
| \\ \\ \\ | \\ \\ \\ | ||
pmip3/design/21k/final.txt · Last modified: 2010/12/06 23:38 by jypeter
