[hkershaw-brown]

Description:

Refactored WRF model mod for WRF & WRF CHEM.
Namelist selectable QTYS, see #404 for details.

Created a wrf_unified model directory. This is to allow concurrent development on wrf and wrf_unified.
wrf_unified/model_mod is ~4500 less than the wrf/model_mod and this is a bit of a headache for keeping up-to-date with main (easy to miss changes in such differing code).

See pull #683 for original pull request
wrf-wrf-chem branch available at https://github.com/hkershaw-brown/DART/tree/wrf-wrf-chem

Fixes issue

Fixes #404
Partial #359 (WRF)
Partial #624 (WRF)

To do:
Follow fixes for

• Using 'lat-lon' map projection in WRF, assigns Cassini projection in DART #811,

• bug: pert_wrf_bc code introduces artifacts to perturbed WRF boundary files #807 from wrf model_mod - Adding new features to WRF scripting and tutorial #1030 forces hybrid_opt in gen_retroc_icbc.sh but not in model_mod.f90

• hybrid coord#649 Add WRF hybrid vertical coordinate  #650 Unified wrf/wrf-chem model_mod #741 (comment)

• static data only in wrf mete domain - test.

• sfc_elev_max_diff

• Forcing QTY_TEMPERTAURE to be QTY_POTENTIAL_TEMPERATURE - this seems incorrect. Edit: updated the comment in bounds_check de9d3f8. The state variable is forced to be qty_potential_temperature. QTY_TEMPERATURE can be interpolated by model_interpolate.

• cloudwater units micrometer vs m

• model_interpolate when zloc is VERTISUNDEF
  

  DART/models/wrf/model_mod.f90

  Lines 1430 to 1436 in a32ab03

  	! Need to convert units
  	! QTY_CLOUDWATER_DE and QTY_CLOUD_ICE_DE are diameters in micrometer (see RTTOV)
  	! but the WRF variable is radius in meter
  	if (obs_kind == QTY_CLOUDWATER_DE .or. &
  	obs_kind == QTY_CLOUD_ICE_DE) then
  	fld = 2.0e6_r8 * fld ! convert to diameter (*2) in micrometer (*1e6)
  	endif

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Documentation changes needed?

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

Tests

Please describe any tests you ran to verify your changes.
Bitwise tests during refactoring: https://github.com/hkershaw-brown/wrf-tests.git

Checklist for merging

• Updated changelog entry
• Documentation updated
• Update conf.py

Checklist for release

• Merge into main
• Create release from the main branch with appropriate tag
• Delete feature-branch

Testing Datasets

• Dataset needed for testing available upon request
• Dataset download instructions included
• No dataset needed

[hkershaw-brown]

For un reviewed atmos-chem forward operators see #743

[Copilot]

Pull Request Overview

This pull request refactors the WRF model_mod for both WRF and WRF CHEM by introducing a unified model_mod and updating corresponding documentation and configuration files. Key changes include:

• Addition of a build script (quickbuild.sh) in the wrf_unified directory.
• Extensive documentation updates in readme.rst describing the unified model and its configuration.
• A new model_mod.nml file with updated configuration and minor comment updates to observation modules.

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
models/wrf_unified/work/quickbuild.sh	Introduces a build script for the new unified model
models/wrf_unified/readme.rst	Provides documentation updates for the unified WRF model interface
models/wrf_unified/model_mod.nml	Defines new namelist settings for the unified model_mod
assimilation_code/modules/observations/default_quantities_mod.f90	Updates observation quantities comments with a new potential temperature entry
assimilation_code/modules/observations/atmosphere_quantities_mod.f90	Updates observation quantities comments with a new potential temperature entry

Comments suppressed due to low confidence (2)

assimilation_code/modules/observations/default_quantities_mod.f90:14

• [nitpick] Consider adding a brief comment that explains the rationale behind adding QTY_2M_POTENTIAL_TEMPERATURE to the observation quantities documentation.

!   QTY_2M_POTENTIAL_TEMPERATURE

assimilation_code/modules/observations/atmosphere_quantities_mod.f90:107

• [nitpick] Consider adding documentation for the inclusion of QTY_2M_POTENTIAL_TEMPERATURE to clarify its intended use and context in the module.

!   QTY_2M_POTENTIAL_TEMPERATURE

[hkershaw-brown]

hybrid coordinate:

"It is mandatory to use the terrain following coordinate
system (hybrid_opt=0)"?
#404 (comment)

DART/models/wrf/tutorial/README.rst

Lines 21 to 28 in 80502a8

	.. Important ::
	This tutorial was designed to be compatible with WRF Version 4 and later, and was
	tested with WRFv4.5.2. It is mandatory to use the terrain following coordinate
	system (hybrid_opt=0) and not the default sigma hybrid coordinates (hybrid_opt=1)
	when using WRF-DART. Using the sigma hybrid coordinate can lead to adverse effects
	when generating ensemble spread leading to poor forecast performance. For more
	details see `DART Issue #650 <https://github.com/NCAR/DART/pull/650>`__.

DART/models/wrf/model_mod.f90

Lines 288 to 290 in 80502a8

	! hybrid_opt 2 is a hybrid coordinate - terrain following at the
	! surface, and straight pressure levels at the top.
	integer, parameter :: VERT_HYBRID = 2

Apparently the "It is mandatory to use the terrain following coordinate
system" is only when using WRF CV3 perturbation to generate the boundary condition perturbed ensemble.

DART/models/wrf/shell_scripts/gen_retro_icbc.sh

Line 70 in 80502a8

echo "ERROR: WRF-DART must use terrain following coordinates, hybrid_opt must be 0"

Needs to be explained in the docs.
Came in in d85b7a0
part of #1030

[hkershaw-brown]

This is in use by CU/DOE collaborators with the addition of #1148

[hkershaw-brown]

note @hkershaw-brown changes for bitwise testing with wrf on
main...hkershaw-brown:DART:model_mod_gc