fv3

Structured YAML to run FV3 is validated by JSON Schema and requires the fv3: block, described below. If FV3 is to be run via a batch system, the platform: block, described here, is also required. The configuration files required by the UFS Weather Model are documented here.

This driver receives a cycle argument, which it makes available as a Python datetime object to Jinja2 when realizing its input config. This supports specification of cycle-specific values. For example, the key-value pair
```
gfs.t{{ cycle.strftime('%H') }}z.atmanl.nc: /some/path/{{ cycle.strftime('%Y%m%d%H') }}/gfs.t{{ cycle.strftime('%H') }}z.atmanl.nc
```
would be rendered as
```
gfs.t18z.atmanl.nc: /some/path/2024021218/gfs.t18z.atmanl.nc
```
for cycle 2024-02-12T18.

Here is a prototype UW YAML fv3: block, explained in detail below:

fv3:
  diag_table:
    template_file: /path/to/diag_table_to_use
  domain: regional
  execution:
    batchargs:
      walltime: "00:10:00"
    executable: ufs_model
    mpiargs:
      - "--export=NONE"
    mpicmd: srun
    threads: 1
  field_table:
    base_file: /path/to/field_table_to_use
  files_to_copy:
    INPUT/gfs_ctrl.nc: /path/to/gfs_ctrl.nc
    INPUT/gfs_data.nc: /path/to/gfs_data.nc
    INPUT/sfc_data.nc: /path/to/sfc_data.nc
  files_to_link:
    co2historicaldata_2010.txt: src/uwtools/drivers/global_co2historicaldata_2010.txt
    co2historicaldata_2011.txt: src/uwtools/drivers/global_co2historicaldata_2011.txt
  lateral_boundary_conditions:
    interval_hours: 3
    offset: 0
    path: gfs_bndy.tile{tile}.f{forecast_hour}.nc
  length: 12
  model_configure:
    base_file: /path/to/model_configure_to_use
    update_values:
      write_dopost: .false.
  namelist:
    base_file: /path/to/base/input.nml
    update_values:
      fv_core_nml:
        k_split: 2
        n_split: 6
    validate: true
  rundir: /path/to/runs/{{ cycle.strftime('%Y%m%d%H') }}
platform:
  account: me
  scheduler: slurm

UW YAML for the `fv3:` Block

diag_table:

template_file:

The path to a Jinja2 template file to be rendered, using the values from the template_values: block for the diag_table file. See FV3 diag_table documentation here.

template_values:

The key/value pairs that are required by the template_file.

domain:

Accepted values are global and regional.

execution:

See this page for details.

field_table:

The path to a valid field-table file to be copied into the run directory.

files_to_copy:

See this page for details.

files_to_hardlink:

Identical to files_to_copy: except that hard links will be created in the run directory instead of copies, when possible. Otherwise a copy will be created.

files_to_link:

Identical to files_to_copy: except that symbolic links will be created in the run directory instead of copies.

lateral_boundary_conditions:

Describes how the lateral boundary conditions have been prepared for a limited-area configuration of the FV3 forecast. Required when domain is regional.

interval_hours:

How frequently the lateral boundary conditions will be used in the FV3 forecast, in integer hours.

offset:

How many hours earlier the external model used for boundary conditions started compared to the desired forecast cycle, in integer hours.

path:

An absolute-path template to the lateral boundary condition files prepared for the forecast. The Python int variable forecast_hour will be interpolated into, e.g., /path/to/srw.t00z.gfs_bndy.tile7.f{forecast_hour:03d}.nc. Note that this is a Python string template rather than a Jinja2 template.

length:

The length of the forecast in integer hours.

model_configure:

Supports base_file: and update_values: blocks (see Updating Values for details). See FV3 model_configure documentation here.

namelist: