PMIP4-CMIP6 ice-sheet data

You will find on this page the boundary condition data that you have to use for the Last Glacial Maximum and the Last Deglaciation experiments Please make sure to read the HOWTO section in order to use the data correctly! Get in touch with the following people if you have questions: Masa Kageyama LGM Ruza Ivanovic Last Deglaciation Didier Roche LGM, Last Deglaciation Jean-Yves Peterschmitt Technical questions

How to use the data

Choose the type of boundary condition you want to use. Look at the available data below, and at the ice-sheet gallery page.

Do not forget to document what you have chosen!

blahblah

After processing the boundary condition data, send a copy the BC data as seen by your model to Jean-Yves Peterschmitt: netCDF file and plot

Ice-sheet data

The input data for the boundary conditions is available in netCDF files provided by Dick Peltier and Lev Tarasov. You will find below some technical details about the data, and the related publications to cite

Data history

The data files may change a bit (rename or standardize the data, etc...) and you will find the change list below

Peltier ICE-6G-C for PMIP4

Grid

nb_lat, nb_lon = 1080, 2160 (regular 10 minutes intervals)

latitude_values = [ -89.91667175, -89.75, -89.58334351, ... 89.58333588, 89.75 , 89.91666412 ]

longitude_values = [ 0., 0.16666667, 0.33333334, ... 359.5, 359.66668701, 359.83334351 ]

NO time axis (1 time step per file)

Time steps and data files

48 time steps in 48 files, from 0k to 26k BP : data every 500 years from 0k to 21k BP, then every 1000 years till 26k BP

file names = I6_C.VM5a_10min.<time_slice>.nc
with <time_slice> in [0, 0.5, 1, ..., 20, 20.5, 21, 22, 23, 24, 25, 26]

all the variables for the same time step are in the same file

Variables

Topo: Topography (Point-value altitude), meters

on continents: surface altitude (including grounded ice sheet)

on ice-free oceans, and where there is floating ice (ice shelves): bathymetry

Orog: Orography (Point-value surface altitude), meters

on continents: altitude (including grounded ice sheet)

on ice-free oceans: 0.0 (zero)

on ice-shelves: surface altitude

sftlf: Point-value Landmask, %

values are 0 (not land) or 100 (land)

does not include floating ice

sftgif: Point-value Icemask, %

values are 0 (not ice) or 100 (ice)

floating ice is included

Notes:

Computing the sftlf-sftgif difference yields:

100: where there is land without ice

-100: where there is floating ice-sheet

0: elsewhere

References

Please cite all following papers:

Describe the new Antarctic component of the model: Argus, D.F., Peltier, W.R., Drummond, R. and Moore, A.W. - The Antarctica component of postglacial rebound model ICE-6G_C (VM5a) based upon GPS positioning, exposure age dating of ice thicknesses, and relative sea level histories. Geophys. J. Int., 198, 537-563, 2014, 10.1093/gji/ggu140

Describe the complete model: Peltier, W.R., Argus, D.F. and Drummond, R. (2015) Space geodesy constrains ice-age terminal deglaciation: The global ICE-6G_C (VM5a) model. J. Geophys. Res. Solid Earth, 120, 450-487, doi:10.1002/2014JB011176

Download

Tarasov GLAC-1D for PMIP4

Grid

nb_lat, nb_lon = 360, 360

latitude_values = [ -89.75, -89.25, -88.75, ... 88.75, 89.25, 89.75 ]

longitude_values = [ 0.5, 1.5, 2.5, ... 357.5, 358.5, 359.5 ]

time axis: see the Time steps section below

Time steps and data files

261 time steps in one file, from 0k to 26k : data every 100 years, from 0k to 26k BP

time_values = [ -26. , -25.9, -25.8, ... -0.2, -0.1, 0. ]

all the variables and all the time steps are in the same file: TOPicemsk.GLACD26kN9894GE90227A6005GGrBgic.nc

Variables

HDC: GLAC contemp. elevation(masl), meters

on continents (including ice sheets) and ice shelves: surface altitude (including ice sheets/shelves)

on ice-free ocean: bathymetry

HDCB: GLAC contemp. elevation(masl), bathymetry for floating ice, meters

on continents (including ice sheets) and ice shelves: surface altitude (including ice sheets)

on ice-shelves: altitude of the bottom of the floating ice

on ice-free ocean: bathymetry

ICEM: GLAC ice mask, fraction

ice fraction values between 0.0 (no ice) and 1.0 (100% ice)

Notes:

The land-sea mask can be computed with:

HDCB > 0 : ls_mask = 1 (land)

HDCB <= 0 : ls_mask = 0 (no land)

Computing the HDC-HDCB difference yields:

ice-shelves thickness where there are ice shelves

0.0 everywhere else

References

Please cite all the following papers:

L. Tarasov and W. Richard Peltier Greenland glacial history and local geodynamic consequences, Geophysical Journal International, 150, 198-229, doi:10.1046/j.1365-246X.2002.01702.x

Lev Tarasov, Arthur S. Dyke, Radford M. Neal and W.R. Peltier, A data-calibrated distribution of deglacial chronologies for the North American ice complex from glaciological modeling, Earth and Planetary Science Letters, Volumes 315–316, 15 January 2012, Pages 30–40, doi:10.1016/j.epsl.2011.09.010

Robert D. Briggs , David Pollard , Lev Tarasov, A data-constrained large ensemble analysis of Antarctic evolution since the Eemian, Quaternary Science Reviews, Volume 103, 1 November 2014, Pages 91–115, doi:10.1016/j.quascirev.2014.09.003

4th paper to be added here (Eurasian component)

Download