ungrib

Structured YAML to run the WRF preprocessing component ungrib (documentation) is validated by JSON Schema and requires the ungrib: block, described below. If ungrib is to be run via a batch system, the platform: block, described here, is also required.

• 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 ungrib: block, explained in detail below:

ungrib:
  execution:
    batchargs:
      cores: 1
      walltime: "00:01:00"
    executable: /path/to/ungrib.exe
  gribfiles:
    - /path/to/dir/rap.t00z.wrfnatf00.grib2
    - /path/to/dir/rap.t00z.wrfnatf06.grib2
    - /path/to/dir/rap.t00z.wrfnatf12.grib2
  rundir: /path/to/run/dir
  start: 2025-07-31T00:00:00
  step: 6
  stop: 2025-07-31T12:00:00
  vtable: /path/to/Vtable.GFS
platform:
  account: me
  scheduler: slurm

UW YAML for the ungrib: Block

execution:

See this page for details.

gribfiles:

A list of paths to the GRIB-formatted files to be processed by ungrib.

rundir:

The path to the run directory.

start:

The validtime of the initial element of gribfiles as an ISO8601 timestamp.

step:

The interval between successive elements of gribfiles as integer hours or as a string of the form hours[:minutes[:seconds]], where the hours, minutes, and seconds components are (possibly zero-padded) integers.

stop:

The validtime of the final element of gribfiles as an ISO8601 timestamp.

vtable:

The path to the correct variable table for the file to be processed by ungrib.