2. Building and Running the UFS Weather Model Land Configurations

2.1. Downloading the Weather Model Code

To clone the ufs-weather-model repository that is capable to run land as a seperate component, execute the following commands:

git clone --recursive https://github.com/ufs-community/ufs-weather-model.git

2.2. Building the Weather Model

The UFS Weather Model uses the CMake build system. The build system is updated to include new land model related applications: LND, ATML and S2SWAL.

Table 2.1 List of applications that supports external alnd component

Application Name	Enabled Components	Short Description
LND	CDEPS, NOAHMP, CMEPS, and FMS	Land model forced by GSWP3 data atmosphere
ATML	FV3ATM, NOAHMP, CMEPS, and FMS	Land model forced by active atmosphere (FV3ATM)
S2SWAL	FV3ATM, MOM6, CICE6, WW3, NOAHMP, FMS, CMEPS	All components used by S2S plus NOAHMP. There is no RT to test this configuration.

To compile the model with land model support, following command can be used for NCAR’s Cheyenne. Note that this is using contol_p8 as an example for CCPP suites. The platform definition can be changed to build model in other platforms such as MSU’s Orion but initial implementation is only tested on NCAR’s Cheyenne at this point.

cd tests
./compile.sh "cheyenne.gnu" "-DAPP=ATML -DCCPP_SUITES=FV3_GFS_v16,FV3_GFS_v15_thompson_mynn,FV3_GFS_v17_p8,FV3_GFS_v17_p8_rrtmgp,FV3_GFS_v15_thompson_mynn_lam3km" noahmp NO NO

2.3. Running NoahMP Specific Regression Tests

Three new regression test are included to test the external NoahMP land component:

Table 2.2 List of regression tests

Test Name	Short Description
datm_cdeps_lnd_gswp3	NoahMP forced by the CDEPS “data atmosphere” using Global Soil Wetness Project v3 forcings. 24 hour forecast with 1 hour coupling interval.
datm_cdeps_lnd_gswp3_rst	Restart reproducibility test (compare results with datm_cdeps_lnd_gswp3)
control_p8_atmlnd_sbs	Side-by-side test that forces external land component with active atmosphere in contol_p8 configuration. This is mainly used to compare land output coming from CCPP/Physics with external NoahMP. In this configuration there is no feedback to active atmosphere.

Newly introduced RTs can be run with following command,

cd tests
./rt.sh -k -n datm_cdeps_lnd_gswp3_rst

cd tests
./rt.sh -k -n control_p8_atmlnd_sbs

The -k basically keeps the run directory for future reference. The user could use this run directory to modify out-of-box configuration for different purposes.