How to tell libIGCM to copy a new input file for ORCHIDEE

Authors: D. Goll and J. Ghattas
Last revision: 2020/02/28, S. Luyssaert

Objective

This help you to: (1) understand why libIGCM is used pass input files and ORCHIDEE and (2) how new input files can be passed to ORCHIDEE by making use of libIGCM.

Why using libIGCM for passing files

The ORCHIDEE code makes use of hard coded file names. Somewhere in the code, for example, there is the instruction to open the file PFTmap.nc which contains a description of the vegetation classified in PFTs for which the ORCHIDEE model was parameterized. When the experiment was configured to simulate land cover change, each year the model will have to read a different file despite it has to be called PFTmap.nc for the ORCHIDEE code to work. This is one of the tasks of libIGCM; if the model is in the year 1901, it will link the path of a PFT map for the year 1901 to the name PFTmap.nc. So, in the year 1901 ORCHIDEE will link the name PFTmap.nc to the PFT map for that year. Depending on the experiment one has in the mind, some input files only need to be read once at the start of the experiment, other need to be read every year, etc. As explained below, libIGCM can take care of this complexity.

Passing input files to ORCHIDEE

Using libIGCM

Read more about setting up an experiment in ​igmcg_doc chapter Setup.

All input files for stomate are set in COMP/stomate.card. Input files for sechiba are set in COMP/sechiba.card for offline simulations and in orchidee.card for coupled simulations. The offline driver forcing files are set in orchidee_ol.card. In these component.card, the input files are divided into different sections :

• [InitialStateFiles]/List : add the file here if it is only needed when no restart file is existing. For example soils_param.nc is set here.
• [BoundaryFiles]/List : add the file depends on the date of the simulation. For example the forcing file is set here. You can use ${year} and ${month} to describe the file.
• [BoundaryFiles]/ListNonDel : add the file here if it is needed during the whole simulation
• [ParametersFiles]/List : add the file here if it is a text file

Syntax: Add in the end of the previous line ",\", be careful not adding empty space and add a new line (sourcefile, destinationfile) where sourcefile is the complete file path and name and destinationfile is the filename read by the model. To define the path for the source file you can use ${R_IN} which points to the shared repository IGCM or set directly the full path to the file.

For the destinationfile you can use "." if the filename is the same.

Examples:

ListNonDel= (${R_IN}/SRF/reftemp.nc, .), \	 
            (path/to/new/file.nc, destinationfilename)

[BoundaryFiles]
List=  (${R_IN}/SRF/METEO/NCC/ncc_for_${year}.nc, forcing_file.nc)

Special case for ENSEMBLE / FLUXNET simulation

Note that the stomate.card and sechiba.card are hidden in here:

config/ORCHIDEE_OL/SPINUP/SUBJOB/OOL_SEC_STO/COMP/

Modify sechiba.card and stomate.card as described above.

Alternatives

In specific cases (i.e., hard core debugging) it could be useful to bypass libIGCM. For most input files this is possible because the file name can also be read from the run.def or orchidee.def files. This is, however, not recommended for any simulations passed the debug stage.