GSL-v8.2.2-2.0

GSL Release Notes - February 2025

MPAS-Atmosphere version 8.2.2-2.0 (initial GSL release - ccfe218)

This is the February 2025 release of MPAS-Atmosphere version 8.2.2, with modifications by the NOAA/OAR/Global Systems Laboratory (GSL) to support GSL-led model development efforts, particularly for prototypes of the Rapid Refresh Forecast System v2. The base for this code is the NCAR-tagged v8.2.2 release of 20 September 2024. The notes below document additions to or changes from that code base.

This release has primarily been developed and tested on the NOAA RDHPCS Jet and Hera resources. Limited testing has been performed on other NOAA RDHPCS platforms. No testing has yet been performed on non-NOAA HPC resources (e.g., NCAR’s derecho). Please use this Github repository’s Issues functionality to report on issues you may encounter with compiling and running our code on these or other resources; however, we are limited in the support we can provide for non-NOAA and non-NCAR HPC resources.

Important Note:

To ensure that all submodules (and therefore all GSL physics) are included, it is recommended to clone the repository and run git submodule update --init --recursive, rather than downloading the tar files from this release.

Physics Changes

• A new suite “hrrrv5” was added, including the Thompson-Eidhammer Microphysics Parameterization for Operations (TEMPO), MYNN-EDMF boundary-layer, surface-layer, and cloud-fraction parameterizations, Unified Gravity-Wave Physics package, RUC land-surface model, and RRTMG shortwave and longwave radiation:

config_microp_scheme       = 'mp_tempo'    
config_convection_scheme = 'off' 
config_pbl_scheme             = 'bl_mynnedmf'                  
config_gwdo_scheme         = 'bl_ugwp_gwdo'       
config_radt_lw_scheme      = 'rrtmg_lw'    
config_radt_sw_scheme     = 'rrtmg_sw'    
config_radt_cld_scheme     = 'cld_fraction_mynn' 
config_sfclayer_scheme    = 'sf_mynnsfclay'  
config_lsm_scheme           = 'sf_ruc'

• The MYNN-EDMF submodule (https://github.com/NCAR/MYNN-EDMF/) was added by GSL as option config_pbl_scheme = 'bl_mynnedmf' , which should not be confused with NCAR’s version (config_pbl_scheme = 'bl_mynn'). This is the same submodule that is now connected to WRFv4.7. It has been refactored to be a k-only scheme with some reduction in computational expense. It is coupled to the radiation with the new option config_radt_cld_scheme = 'cld_fraction_mynn'. This submodule adds additional bullet-proofing for incoming negative nc, ni, nwfa, and nifa, and additional namelist controls (bl_mynn_mixnumcon and bl_mynn_mixaerosols) to determine mixing of number concentrations and aerosols (defaults both set to 1, “active”). There has been a revision of the stratus subgrid clouds to better work for MPAS/WRF and some tuning to improve the strength of LLJs and low-level shear for WFIP3. The latter includes a modification to the stable component of the hybrid PBL height. There is a new downdraft module for cloud-top radiative cooling in stratocumulus, which works reasonably well but needs more testing. We also added some hurricane-specific tuning that is isolated to high wind speed conditions over water. The most recent addition is a new explicit finite differencing for the mass-flux scheme (from Kay Suselj NASA-JPL), activated by setting bl_mynn_edmf = 2 (not active by default), but this is still considered experimental.
• The MYNN surface layer was added by GSL as option config_sfclayer_scheme = 'sf_mynnsfclay', which should not be confused with NCAR’s version (config_sfclayer_scheme = 'sf_mynn'). Currently, this version is very similar to NCAR’s version, but has some hurricane-specific tuning and some small changes taken from the CCPP version. This version is meant to be submodularized within the upcoming year, added as a submodule within NoahMP, and universalized with the CCPP version, but most of this work has not yet been started.
• TEMPO was added as config_microp_scheme = ‘mp_tempo’. TEMPO stands for the Thompson-Eidhammer Microphysics Parameterization for Operations. TEMPO is a modular version of the Thompson-Eidhammer scheme that lives in a submodule (https://github.com/NCAR/TEMPO). Current options include ‘config_tempo_aerosolaware’ (true by default) that uses the aerosol-aware version of the scheme described in Thompson and Eidhammer, 2014: (https://doi.org/10.1175/JAS-D-13-0305.1). Additionally, a version of the scheme with 2-moment graupel with predicted graupel density, or hail-aware TEMPO, (see Jensen et al., 2023: https://doi.org/10.1175/MWR-D-21-0319.1) can be used by setting ‘config_tempo_hailaware’ (false by default). The hail-aware version of the scheme requires new lookup tables that can be built by setting ‘build_hail_aware_table = .true.’ in module_mp_tempo_params.F90, compiling core_atmosphere (MPAS), and running the compile-time created executable, ‘build_tables_tempo’. TEMPO is designed for community development, and contributions are welcome. Please reach out to Anders Jensen [email protected] for any questions.
• The Grell-Freitas cumulus parameterization is available in this GSL version of MPAS. In this release, we introduced a new scale aware technique for GF deep convection (Grell-Fieitas, 2014) in the gray zone. It is controlled by the namelist option of config_gf_sub3d. If config_gf_sub3d=0, the traditional scale-awareness (Grell and Freitas 2014) is applied. If config_gf_sub3d=1, the new scale-awareness approach is applied (Grell et al., 2025). The traditional scale-awareness approach is from Arakwa et al. (2011) that scales the cloud-base mass flux in dependence on convective area fraction. It fails to consider the fact that the impacts of deep convection on those scales are not limited to one grid box. In addition, it appears to assume that both parameterization and explicit microphysics and dynamics should be active at the same grid point. With the traditional scale-awareness, the precipitation from the convective scheme may be scaled down by up to a factor of 100, depending on resolution. This is very unphysical, especially if the microphysics is not active yet, and the dynamics cannot resolve any part of the storm system. The new approach assumes that the feedback terms due to compensating mass fluxes can be separated from the other tendencies. We separate the terms due to the compensating mass fluxes of updraft and downdraft from the lateral mixing related terms in the convective parameterization and then spread the subsidence terms only over the neighboring grid points. This new approach avoids any scaling, and the precipitation rates are unchanged. Further developments and bug fixes for this new approach are forthcoming in future releases. A simplified cold-pool parameterization is also only included in this release.
• RUC LSM is available in this GSL version of MPAS. It is located in the src/core_atmosphere/physics/physics_wrf directory. The RUC LSM has two modules: one for land called out of mpas_atmphys_driver_lsm.F, and another is for ice called from maps_atmphys_driver_seaice.F. RUC LSM can be used with all physics suites, but it is a default in the HRRRv5 suite. The RUC LSM option is activated by setting in the namelist.atmosphere:

config_lsm_scheme    = 'sf_ruc'
num_soil_layers      = 9

The soil state variables can be initialized from RAP, HRRR, RRFS and GFS. The
following parameters has to be used in the namelist.init_atmosphere to initialize 9 levels in the RUC LSM:

config_nsoillevels = 9
config_nfgsoillevels = 9 (or 4 for GFS)

The 15” vegetation information and BNU soil classifications are added to MPAS to match
the information used in RAP and HRRR. This static information is recommended for use with the RUC LSM and it can be produced on the MPAS static step by setting:

config_landuse_data = 'MODIFIED_IGBP_MODIS_NOAH_15s'
config_soilcat_data = 'BNU' 

There is an option to initialize the vegetation greenness fraction from the real-time RAP/HRRR/RRFS information by setting: config_nvegopt = 2 in the namelist.init_atmosphere and config_gvf_update = false in the namelist.atmosphere.
The 2-m diagnostics over land and ice is computed using module_sf_sfcdiags_ruclsm.F located in src/core_atmosphere/physics/physics_wrf.

• The Unified Gravity Wave Physics (UGWP) suite of drag parameterizations was added as config_gwdo_scheme = bl_ugwp_gwdo. The UGWP was developed for the UFS, and is soon to be operational in GFSv17 and GEFSv13. It consists of drag schemes related to stationary (orographic) sources and non-stationary (convective and frontal instability) sources. Note that the stationary components of the UGWP is the "NOAA/GSL" orographic gravity wave drag (GWD) suite introduced in WRF Version 4.3 (activated by WRF namelist option "gwd_opt=3"). The non-stationary GWD component is activated by the namelist option ‘config_ngw_scheme = true’. Instructions on creating the necessary static files with ‘init_atmospere_model’ and running the scheme can be found on the wiki page.

General Changes

None apart from those noted above.

Known Issues

• mesoscale_reference suite does not reproduce NCAR v8.2.2 code
  • this has been fixed with v8.2.2-2.3 (PR #83)
• convection_permitting suite does not reproduce NCAR v8.2.2 code
  • reference: issue #66, issue #75
• init_atmosphere ha...