Change component set

Change component set#

Exercise: Repeat the 1 month from your first I1850 experiment with a different CLM compset

Choose which CLM compset you want to run:

  • CLM-BGC: I2000Clm60BgcCrujra
  • CLM-BGC Crop: I2000Clm60BgcCropCrujra
  • CLM-FATES SP: I2000Clm60FatesSpCrujraRsGs

Create a case using the selected compset using f19_f19_mt233 resolution.

Note: You will still need to use the “–run-unsupported” flag.

Check the status of the run after submitting.

Background on compset longnames:#

We can use a different I compset, for example IHistClm60BgcCrop. This experiment is a 20th century transient run using GSWP3 forcing and the biogeochemistry model including crops.

Using query_config again we learn more about this compset:

cd /glade/u/home/$USER/code/my_clm_code
cime/scripts/query_config --compsets clm | grep "IHistClm60BgcCrop "

Which will return the following:

   IHistClm60BgcCrop    : HIST_DATM%GSWP3v1_CLM60%BGC-CROP_SICE_SOCN_MOSART_SGLC_SWAV

Which breaks down into:

Field

Description

HIST

Historical transient starting in 1850

DATM%GSWP3v1

Data Atmosphere Model using GSWP3v1 forcing

CLM60%BGC-CROP

CTSM with clm6_0 physics defaults for big-leaf model with Biogeochemistry and Prognostic Crops

SICE

Stub Sea-ice

SOCN

Stub Ocean

MOSART

MOSART River model

SGLC

Stub Glacier model

SWAV

Stub Ocean Wave model

In biogeochemistry (BGC) mode, CLM grows vegetation rather than prescribing it, computing photosynthesis, allocating carbon to leaves, stems, and roots, and cycling carbon and nitrogen through vegetation, litter, and soil. Leaf area becomes a prognostic result of that carbon balance rather than a satellite input, which makes BGC far better for studying how vegetation responds to change, but costlier, since the carbon pools must be spun up to equilibrium first.

By default, IHIST compsets have a default finidat (initialization file) that they use to initialize the model. We will leave this at default.

Get started running with one of the compsets listed above:#

  • What kind of experiment are you wanting to run?

  • What model configuration seems most appropriate?

Click here for hints

The example below assumes that you want to run an I2000 case with FATES in Satellite Phenology (SP) mode.

Your reality may be different from this.

Are you in the right workspace?

Navigate to my_clm_code/cime/scripts before running the ./create_newcase command

cd /glade/u/home/$USER/code/my_clm_code/cime/scripts

Did you give your new case a new name?

You can create a new case with the command:

NEW_CASE_NAME='i2000_fates_sp.basics'
./create_newcase --case /glade/u/home/$USER/cases/$NEW_CASE_NAME --res RES --compset COMPSET --run-unsupported

Did you navigate to the case directory to set up the case?

You can invoke case set up as follows:

cd /glade/u/home/$USER/cases/i2000_fates_sp.basics
./case.setup

Did you remember to extend the length of the run to 1 month?

./xmlchange STOP_OPTION=nmonths
./xmlchange STOP_N=1
Click here for the solution

Create a new case i2000_fates_sp.basics with the command:

cd /glade/u/home/$USER/code/my_clm_code/cime/scripts
./create_newcase --case /glade/u/home/$USER/cases/i2000_fates_sp.basics --res f19_f19_mt233 --compset I2000Clm60FatesSpCrujraRsGs --run-unsupported

Case setup:

cd /glade/u/home/$USER/cases/i2000_fates_sp.basics 
./case.setup

Change the queue to the ‘tutorial’ queue:

./xmlchange JOB_QUEUE=tutorial --force

Extend the length of the run to 1 month:

./xmlchange STOP_OPTION=nmonths
./xmlchange STOP_N=1

Build and submit:

qcmd -- ./case.build
./case.submit

Check the status:

qstat -u $USER

When the run is completed, look into the archive directory for: i2000_fates_sp.basics.

Check that your archive directory on derecho (The path will be different on other machines):

cd /glade/derecho/scratch/$USER/archive/i2000_fates_sp.basics
ls

Advanced: Comparing the namelist settings#

When you create a case, CLM uses the compset to build the namelist for each component. The namelist, lnd_in, tells CLM which input files to read and which options to turn on. A copy of the final namelist is saved in each case’s CaseDocs/ directory.

Because the compset determines these settings, comparing lnd_in between your two cases shows how the configurations differ. The diff command prints only the lines that differ between two files. Lines starting with < come from the first file and lines starting with > from the second.

Look for differences in:

  • Input files, such as the surface dataset (fsurdat), initial conditions (finidat), and parameter file (paramfile)

  • Model options, such as use_crop or use_fates

For each difference, ask: why would this compset need this setting?

diff ~/cases/i1850_sp.basics/CaseDocs/lnd_in ~/cases/i2000_fates_sp.basics/CaseDocs/lnd_in

Test your understanding#

  • Where would you look to find out what other compsets are available?

  • What do the Rs and Gs mean in the FATES compset name?

  • What atmospheric meteorological forcing data is being used? Are there other options?

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