CCPP AMS2020 Short Course | SCM and CCPP suites

Review the physics suites

We’d like to run several experiments with the SCM, showing differences among 3 physics suites for two different meteorological regimes. Let’s first take a look at the composition of the physics suites and then how the two cases are set up.

Navigate to the directory where available suite definition files are stored and see what is available:

cd code/gmtb-scm/ccpp/suites
ls

We’re interested in the following suites: suite_SCM_GFS_v15p2.xml, suite_SCM_GSD_v1.xml, and suite_SCM_csawmg.xml

Notice the XML format, paying attention to the key elements: suite (with name attribute), group, subcycle, scheme.

Supplemental Slides 2-6 review the syntax of suite definition files.

You will find primary and interstitial schemes.  All suites share many common elements, particularly interstitial schemes that are required to prepare data for schemes and calculate diagnostics expected in a GFS run, since they were constructed by modifications to the original GFS operational suite. 

Supplemental Slides 7-8 show the differences between the operational GFS suite and the experimental GSD_v1 and csawmg suites.

Navigate to the directory where case setup namelists are stored to see what we’re going to run.

cd ../../scm/etc/case_config
ls

Look at twpice.nml to see what kinds of information are required to set up a case. The variables most likely to differ among cases are: case_name, dt, runtime, [thermo,mom]_forcing_type, sfc_flux_spec, year, month, day, hour.

See supplemental slide 9.

Each case also has a netCDF file associated with it (determined by the case_name variable) that contains the initial conditions and forcing data for the case. Take a look at one of the files to see what kind of information is expected:

ncdump -h ../../data/processed_case_input/twpice.nc | more

There are groups for scalars (single values relevant for the simulation), initial conditions (function of vertical level only), and forcing (function of time and/or vertical level). Note that not all forcing variables are required to be non-zero.

See supplemental slides 10-12.