How to run future offline simulations?

Author: M. McGrath
Last revision: B. Guenet (2020/03/19)

In theory, running future simulations offline is no different than running current simulations, assuming you have the driver files. Getting the driver files can be a bit more tricky.

There are several options to create the forcing files. See here two basic options:

  • Using ISIMIP2B data

Or you can benefit from the work done during the ISIMIP project and download the bias corrected simulated climate from several ESM. Data can be download here you must have an account but then no registration are needed to download the data. Please note that it doesn't work well for me when using Firefox but works perfectly with Chrome. Once you download the data some work is still necessary to have all the forcing needed by ORCHIDEE. First you needed to concatenate all the necessary forcing into one file (LWdown Psurf Qair Rainf SWdown Snowf Tmax Tmin Wind), make sure that the units, the name and the dimensions are consistent with ORCHIDEE expect. Then, you need to have one file per year (for this you can use the script written below).

Once your files are ready, please contact the help list (orchidee-help@…) to propose to share the download data with the other but storing them on the share directory. You can check those already downloaded here ${R_IN}/SRF/METEO.

The pros using ISIMIP2B is that you can have access to several ESM outputs and not only the IPSL-ESM. The cons are that if you're interested in a very particular setup it might not be available on the ISIMIP2B plateform.

  • Using a simulations done with the IPSL model

It seems that Patricia Cadule, Fabienne Maignan (working from files pre-treated by Patricia), and Nicolas Viovy are the three people who know something about future driver data (that is, driver data taking from the results of CMIP5 simulations for the years 2006-2100). Working from the files that Nicolas has used is also a bit tricky depending on which version of ORCHIDEE you are using, since they are currently formatted for his input driver and so require a little bit of change to work with the trunk. We did this first by running the following bash script on Curie but it should work for Irene too.


varnames=(LWdown Psurf Qair Rainf SWdown Snowf Tmax Tmin Wind)

syear=(2006 2011 2021 2031 2041 2051 2061 2071 2081 2091)
eyear=(2010 2020 2030 2040 2050 2060 2070 2080 2090 2100)

for igroup in 0 1 2 3 4 5 6 7 8 9
    echo "On year ${syear[$igroup]}"
    export inputfilename="ipsl_rcp4p5_${syear[$igroup]}-${eyear[$igroup]}.nc"
    for ((year=${syear[$igroup]}; year<=${eyear[$igroup]}; year++))
	echo "On year $year"
	export outputfilename=ipsl_rcp4p5_$
	rm -f $outputfilename 
	# Calculate the number of days in this year
	sday=$((($year-${syear[$igroup]})*$ndays_year+1 ))
	eday=$((($year-${syear[$igroup]}+1)*$ndays_year ))
	echo "Days: $sday $eday"
	for ivar in {0..8}
	    rm -f
	    echo "On ${varnames[$ivar]},${sindex[$ifile]},${eindex[$ifile]} "
	    ncea -F -d time,$sday,$eday /ccc/scratch/cont003/dsm/p529viov/isimip/ipsl/i${varnames[$ivar]}_$inputfilename
	    ncks -A -o $outputfilename
	    rm -f

The above script combines the forcing from 2006-2100 that Nicolas uses into annual files. From there, additional work still needs to be done. In particular,

1) The order of the variables is not necessarily the same as the CRU-NCEP files. ORCHIDEE is very picky about the input files, so you'll have to make sure that the order of the variables and all meta data/axis are exactly the same as found in the existing CRU-NCEP files to make it work.

2) All years are daily, not 6-hour timesteps. In theory, ORCHIDEE can use a weather generator to account for this, but don't be surprised that the files are smaller than CRU-NCEP (all years have 365 days).

3) There are no Wind_N and Wind_E variable, only WIND. It seems like a good idea is to assign the value of WIND to Wind_E, and then set Wind_N equal to zero, since apparently in the offline mode the wind is always converted to the magnitude and therefore the direction does not matter.

4) There is no precip (needed by the weather generator for daily files). It seems that you can combine Snowf and Rainf, and then the weather generator using the temperature to decide what is rain and what is snow.

Last modified 4 years ago Last modified on 2020-03-23T08:38:42+01:00