WRF Version 4.6.0

This is the Version 4.6 release of the WRF Model. This release includes all components of the system: WRF-ARW, WRF-Chem, and WRFDA.

Acknowledgements: We would like to thank Kasra Shamsaei (University of Nevada, Reno), Tim Juliano, Domingo Munoz-Esparza, Branko Kosovic (NCAR/RAL), Jun Tang (Amazon), RenChuanhua and Huangxin (Nanjing University), David Robertson (Rutgers University), Kasra Shamsaei (University of Nevada, Reno), Tim Juliano, Branko Kosovic (NCAR/RAL), Cristina Archer (UDEL), Yulong Ma(UDEL;GWA-MWF), Ahmad Vasel-Be-Hagh(Tennessee Technological University), Zhixiong Chen (Fujian Normal University, China),JJ Guerrette (NCAR/MMM, now at tomorrow.io), Deqin Li (Liaoning Meteorological Bureau of CMA), Cenlin He (NCAR), Joseph Olson (NOAA), Laura Fowler (NCAR), Sergey Osipov (KAUST), Daniel Wesloh (Penn State), Do Ngoc Khanh (Tokyo Institute of Technology), Jordan Schnell (NOAA), Soren Rasmussen and Ryan Cabell (NCAR),Parag Joshi and Katia Lamer (Brookhaven National Lab), and Ted Mansell (NOAA) for their contributions to this release.

New features in WRFV4.6

Physics

• Add revised MM5 surface layer scheme from the future shared MMM-physics repository. Detail
• Add new Tiedtke cumulus scheme from the future shared MMM-physics repository. Detail
• Add WSM6 microphysics scheme from the future shared MMM-physics repository. detail
• Add YSU PBL scheme from the future shared MMM-physics repository. Detail
• Add GWDO (gwd_opt=1) code from the future shared MMM-physics repository. Detail
• Add two options (slucm_distributed_drag and distributed_ahe_opt) to WRF SLUCM (sf_urban_physics = 1) so that spatially varying urban morphological parameters (building height, plan area index, frontal area index, roughness length for momentum, and displacement height) can be considered. Detail
• Add salinity effect in MM5 and revised MM5 surface layer schemes. The effect is lower the saturation vapor pressure over ocean by about 2%. Detail
• Add options for three new wind farm parameterizations and their ensembles to account for the individual and overlapping sub-grid wakes of wind turbines within a wind farm. It is recommended to use the new wind farm parameterizations, particularly for coarse resolution, high turbine density, and wind directions aligned with the turbine columns. Detail
• Add 3-moment option to NSSL microphysics scheme (for rain, graupel, and hail) (mp_physics=18). Changes to snow aggregation parameters reduce stratiform reflectivity bias. Also add namelist options to enable/disable bulk CCN prediction and graupel/hail density prediction, and deprecate old mp_physics options (17, 19, 21, 22). Main default parameter changes are for graupel/hail fall speed options (icdx, icdxhl; changed from 3 to 6), and default maximum gr/hail droplet collection efficiencies (ehw0/ehlw0 changed from 0.5/0.75 to 0.9/0.9) See doc/README.NSSLmp for details. A problem is fixed for high resolution vertical domains with nz > 128, where hydrometeor sedimentation did not work at k > 128 (this bug affected most or all previous releases). Detail

Real-Data initialization

• Add a new namelist option "use_sh_qv = T" to allow for choosing to use SH or Qv data directly. If water mixing ratio or specific humidity is available in the metgrid output, they can be used directly in vertical interpolation. Previously these fields are first converted to RH, interpolated vertically, and the water vapor mixing ratio is computed at model levels.Detail

Data assimilation

• Add the capability for assimilating GOES-ABI radiance data. Detail
• Add a lightning data assimilation scheme to assimilate pseudo vertical velocity, divergence fields, or water vapor retrievals from lightning flash rate data. Detail
• Add a background-dependent hydrometeor retrieval scheme for indirect radar reflectivity assimilation. Detail

WRF-FIRE

• Add Scott and Burgan (2005) 40 fuel models for WRF-Fire. Detail
• Add a new Truncated Gaussian scheme to distribute fire heat and smoke in the atmosphere. Detail.

Chemistry

• Add WRF-SoilN-chem, a dynamic ammonia emission model capable of calculating NH3 emission rate interactively with time- and spatial-varying meteorological and soil conditions. Detail

Compiling

• Introduce a CMake build system for em_real and em_ideal as an optional compilation method. Detail. Users are welcome to try and provide feedback.
• Add CMake build option to WRF-Hydro. General bug fixes and code cleanup are also done. MPI routine is more efficient. All hydro file suffixes are now .F90. Detail

Bug fixes and enhancement in WRFV4.6

Physics

• Correct net long wave fluxes for application in modeling urban climate using Single Layer Urban Canopy Model (SLUCM). It slightly improved 2-m temperature in urban area. Details
• Change the behavior of the mp_zero_out flag so that it affects only the 'moist' array, whereas previously it also caused the scalar/chem/tracer arrays to also be set to zero for values below threshold. Now there is a separate flag (mp_zero_out_all) if one wishes to reproduce the old behavior. Details
• Move the call to shalwater_init from module_sf_sfclayrev.F to module_physics_init.F. This is in preparation to make sfclayrev module ccpp-compliant, and potentially make the initialization and physics available to other surface layer modules. Detail
• Fix a bug in Noah-MP for uninitialized leaf mass when LCZ is used. Detail
• Update urban LCZ parameter table (URBPARM_LCZ.TBL) with more reasonable values. Detail
• Update MYNN-EDMF . Detail
• Fix bugs in Noah-MP for snow combination, vegetation fraction scaling, and urban ground heat flux sign. Detail
• Remove zero negative latent heat flux limit (atmosphere to water) in the revised MM5 and original MM5 surface layer schemes. Detail
• Make the Pleim-Xiu LSM compatible with MODIS LCZ. Also, effects of evaporation from transpiration, soil in both vegetated and non-veg parts and wet leaves on ground temperature all are considered. Previously only the effect from transpiration and evaporation from non-veg soil are considered. Detail
• Modify the RUC LSM to add options to the snow model, use real-time vegetation fraction as an indicator for irrigation scheme, and change soil diffusional and hydraulic conductivities. Detail
• Correct diffusion coefficients for tke in LES. Detail

Chemistry

• A building issues with Intel compilers (ifx/icx) for WRF/WRF-chem is addressed. Detail
• Add KPP configure option for alternative libfl name, libfl.so, in addition to libfl.a. Detail
• Fix n2o5 heterogenous namelist option for MADE schemes. Detail
• A bug was introduced after splitting chem_opt 100 and 106. Currently, the chemistry initialization always calls for module_aerosol_soa_vbs routine, leaving the module_aerosol_soa_vbs_HET and corresponding data constants unitialized. As a result, aerosol concentrations are set to 0 after the first time integration (10**-16). This bug is fixed by Differentiate between module_aerosol_soa_vbs and module_aerosol_soa_vbs_het initialization routines. Detail
• Update the registry description for settling velocity of bi...

WRF Version 4.5.2 (Bug-fix Release)

The WRF model has been updated to Version 4.5.2 on December 22, 2023.

Acknowledgements: We would like to thank Mathieu Landreau (LHEEA, Centrale Nantes, France), Marc Imberger (Technical University of Denmark), Alexander Knyazev (Intel), Wei-keng Liao (Northwestern University), Jun Tang (Amazon), Zhixiao Zhang (University of Oxford), Jacob Shpund (Pacific Northwest National Lab), Timothy Brown (AWS), Songyou Hong (PSL/NOAA), Dan Li (Boston University), David Robertson (Rutgers University), Cenlin He (NCAR RAL) for their contributions to this release.

This is a bug fix release. Following are fixes associated with this release.

Physics

• Fix two errors in the WDM6 and WDM7 that have been in the code since V4.0: (1) uninitialized cloud number concentration when cloud is present at the start, and (2) The cloud autoconversion rate was off by a factor of 600. The effect of the first error isn't large, but the effect of the wrong autoconversion rate has resulted in doubling the surface rainfall in some tests (warm rain processes). Details
• Fix a typo in computing saturated specific humidity in the single-layer urban canopy model. The effect is likely small since the calculation is relevant only in the case of rain and on impervious surfaces when using default evaporation scheme (which is set in URBPARM.TBL). Details
• Fix the calculation order in the immediate melting, which was erroneous and based on the hydrometeor state after melting in previous version. In addtion, the calculation method in the supersaturation dynamical tendency is changed to avoid high values of total mass imbalance.Details
• Fix a bug in the code related to trigger condition for CAPE calculation. Details
• Add missing wrf_dm_bcast_real for stc2 in fitch parameterization scheme, which affects standing thrust coefficients for wind speeds at turbine hub-heights above cut-out. Details
• Fix an issue in which time series for a parent domain were re-initialized when a child domain started later than the initial time for a simulation. Details

Compiling

• Add build configuration for new Intel oneAPI LLVM ifx/icx compilers, which is available on NCAR's new computer (Derecho). Details. Note that the option does not yet work for WRFDA and WRF-Chem compilation.
• The fortran library can be either hdf5_hl_fortran or hdf5hl_fortran for HDF5, which is now checked in Config.pl. Details
• Improve the detection and linking with shared and static configurations of the NetCDF-4 libraries (split or unified) inside and outside Spack-Stack to avoid issues when NetCDF-C and NetCDF-Fortran reside in different directories Details
• Add compile defaults for Arm Compiler (armclang/armflang) for Linux. Details
• Resolves building issues with Intel compilers (ifx/icx). Details
• Fixed an error in Makefile to check if USENETCDFPAR is set first. Details

Dynamics

• Fix loop ranges in advect_w for lat-long map projection. This fix only affects polar boundary condition. Details

NOTE!!!! : If downloading the files from the section below, please choose either the v4.5.2.tar.gz file, or the v4.5.2.zip file. DO NOT choose those named "Source Code." They do not include the mandatory NoahMP submodule - needed for compiling WRF.

WRF Version 4.5.1 (Bug-fix Release)

The WRF model has been updated to Version 4.5.1 on July 25, 2023.

Acknowledgements: We would like to thank Stephen Sachs (AWS), Greg Thompson (NCAR RAL), Michael Laufer (Israel), Andrea Zonato (Koninklijk Nederlands Meteorologisch Instituut), Cenlin He (NCAR RAL), Becky Adams-Selin (Atmospheric and Environmental Research),Samm Elliott (TempoQuest Inc.) for their contribution to this release.

This is a bug fix release. Following are fixes associated with this release.

Physics

• Correct the counter-gradient term for temperature equation at the first level in the KEPS scheme (bl_pbl_physics=17), which causes instabilities and large biases at the first model level over water surfaces. Details
• Make Minor changes to Thompson-MP to align with changes made in CCPP for use in UFS. Details
• Fix a bug related to FVEG scaling of canopy heat storage in Noah-MP canopy energy balance calculations. Details
• Fix problems in HAILCAST quilted processes/tiling and some incorrect SI/non-SI unit conversions. Details
• Fix a bug in building height specification in the LCZ urban parameter table. Details
• Fix an issue in the revised MM5 (sf_sfclay_physics=1) scheme, where the model could potentially encounter an infinite loop. In specific conditions floating point roundoff errors were preventing a convergence condition from ever being met. Details

Compiling

• Make configure script more portable. Details
• Fix the ADIOS2 init API to support ADIOS2 v2.9.0. Details
• Apply type-mismatch for gcc-10 to all gcc targets. Details

Miscellaneous

• Replace a few wrf_messages and wrf_error_fatal calls by macros defined at the top of modules for urban schemes so that the code maintains consistency with those in MPAS. Details
• Update references and remove obsolete contact information related to lightning options (lightning_option = 1 and 2). Details
• Add User-friendly fatal error messages if the optional CESM aerosol data files required for the MSKF cumulus/Morrison microphysics aerosol interaction option (aercu_opt = 1 or 2) are missing. Details
• Remove the file "test/em_real/namelist.input_default", which is more confusing than helpful for users. [Details] (b552930)

NOTE!!!! : If downloading the files from the section below, please choose either the v4.5.1.tar.gz file, or the v4.5.1.zip file. DO NOT choose those named "Source Code." They do not include the mandatory NoahMP submodule - needed for compiling WRF.

WRF Version 4.5

This is the Version 4.5 release of the WRF Model. This release includes all components of the system: WRF-ARW, WRF-Chem, and WRFDA.

Acknowledgements: We would like to thank Cenlin He (NCAR RAL), Greg Thompson (JCSDA, UCAR), Anders Jensen (RAL, NCAR), Dylan Reynolds (SLF), Joseph Olson (NOAA-GSL), Wayne Angevine (NOAA-CSL), Andrea Zonato (Department of Environmental, Civil and Mechanical Engineering, University of Trento, Trento, Italy), Jun Tang (Amazon), Jeff Adie (NVIDIA Corporation), Hugh Morrison (NCAR-MMM), Brian Vanderwende (NCAR), Jordan Schnell (NOAA), Kengo Miyamoto (RIST), Zhang Chunxi, Maria Frediani (NCAR RAL), Michael Laufer (Toga Networks, a Huawei Company), Erick Fredj(The Jerusalem College of Technology, Rutgers University, Toga Networks, a Huawei Company), Joseph Brodie (Rutgers University), Lori Garzio (Rutgers University), Sen YANG, Deqin LI, Liqiang CHEN (Institute of Atmospheric Environment, China Meteorological Administration, Shenyang) for their contributions to this release.

New features in WRFV4.5

Physics

• A new package to compute two-moment prognostics for graupel/hail and a predicted density graupel category is added in the Thompson scheme (mp_physics=38). Other updates to the scheme include a change to the Y-intercept relationship for one-moment graupel and replacement of air temperature for wet-bulb temperature in riming and mixed phase processes (Jensen et al., in review). This code requires the datafile "qr_acr_qg_mp38V1.dat" to run, which can be found on the file system for the NCAR community HPC "Cheyenne" under /glade/work/wrfhelp/WRF_files/ and online at http://www2.mmm.ucar.edu/wrf/src/wrf_files/. Details
• A scale-aware or grid-distance-dependent option is added to the new Tiedtke scheme. The code is based on the paper by Wang (2022) with two minor changes removed. The option becomes active automatically when grid sizes is less than 15 km. PR1806 and PR1840
• A new k-epsilon-theta^2 PBL scheme, including two additional prognostic equations for dissipation rate and temperature variance, has been included in the WRF model (see Zonato et al.,2022:A New K–ε Turbulence Parameterization for Mesoscale Meteorological Models. Monthly Weather Review, DOI: https://doi.org/10.1175/MWR-D-21-0299.1). This scheme is designed for finer grids. It works with sfclay=2(time step = 90), sfclay=1(time step = 60), diff_opt=1 km_opt=4). Details

Compiling

• Add support to build WRF on ARM64 (aarch64) architecture systems with the NVIDIA HPC SDK Compilers (nvfortran,nvc). Details
• Provided AMD AOCC Compiler support at the time of configuring WRF for AMD Architectures including Zen1, Zen2 and Zen3. Details

Bug fixes and enhancement in WRFV4.5

Physics

• Substantial updates are added to the MYNN-EDMF, including a reorganization of the subroutines as part of the “universalization efforts”, which are meant to keep the scheme similar in all dycores. The major physics changes include (1) improved conservation of scalars which improves performance in medium-range global forecasting, (2) revised subgrid clouds which leverages the prognostic q’2, (3) vacate bl_pbl_physics = 6 (now only run with bl_pbl_physics = 5); will instead regulate the closure level with new namelist variable “bl_mynn_closure” set to 2.5, 2.6, or 3.0, (4) important bug fixes for the TKE budget and the bl_mynn_tkebudget flag is not renamed to tke_budget for use in other schemes (although may not be hooked up for other schemes yet), (5) new downdraft option (hidden hard-coded flag in module_bl_mynn.F) but still under development to best fit within the MYNN-EDMF, (6) and many miscellaneous tuning/minor bug fixes.Details
• Fix an error with O31D exceeding vertical dimension kte. In WRFV4.4, we introduced ozone output o3rad when o3input = 0, that is to use ozone profile provided by the RRTMG code. But the use of output array accessed memory with the vertical dimension > kte. This can cause segmentation fault on some systems. Details
• Update P3 microphysics. Details
• Bug fix for the vertical levels of TKE in the EEPS scheme and more features are added in this scheme. Details
• Fixed a bug for lightning diagnostic option 3, an option for lightning potential index calculation. The bug prevented nested case to run, and may produce NaNs in the diagnostics. Details
• Fix an issue in roof longwave calculation in the bep_bem urban scheme (module_sf_bep_bem.F), in which a misplaced parenthesis is corrected. Details
• The hard-coded tunable canopy heat capacity parameter in Noah-MP is added to MPTABLE for the convenience of tuning. Details
• Fixed a dimension error for arrays refl, t and z in module_ltng_crmpr92.F.Details
• Update hydro directory to match WRF-Hydro v5.3.0. Details
• NoahMP submodule is updated to its v4.5 branch.Details

Compiling

• Stop intentionally removing OpenMP flags when compiling certain listed source program files, which causes problems with a Fujitsu Fortran compiler. Details
• Change configure to test for RPC package instead of checking hardcoded paths, so that non-standard RPC installs can still be found. Details
• Fix numerical divergence on x86 and arm64. It is recommended to use armclang for best performance of WRF on arm64. Details
• Correct string test in configure to avoid 'Unexpected Operator' error. Details

Data assimilation

• Add a regularized version of WSM6 and its TL/AD for 4DVar with ice-phase hydrometeor analysis variables.Details
• Enhance AHI radiance DA, including all-sky observation error model, Level-2 AHI product read, and more diagnostic output. Details

Chemistry

• Address a bug introduced in WRF v4.3 that affects users using chem_opts = 201 (MOZART_MOSAIC_4BIN_KPP) and 202 (MOZART_MOSAIC_4BIN_AQ_KPP). Users experienced a stalled simulation upon writing history files. This was caused by the pH diagnostics added in v4.3 (#1342) not being activated with the namelist option mozart_ph_diag = 1. Details
• Add an option to use GFS total ozone (2D) in the TUV photolysis (phot_opt=4) to scale the simulated column to the GFS total column in the calculation of photolysis rates. Details
• chem_opt=100 is separated from chem_opt=108 and 109. This is because species in chem_opt=100 (HCL, CLNO2, MG, K, CA) are referenced by the aerosol module for chem_opt=108, 109 leading to memory mapping errors. Details

WRF-Fire

• Update the firebrand spotting parameterization to (1) allow likelihood of spotting on short grass and (2) fix the location and height of ember release. Details

###Miscellaneous

• Fix two numeric operators that are consecutive. Details
• Change the exponent letters of the constants those are compared to double precision variables in SUBROUTINE FIND_RC0 from ‘E’ to ‘D’. Details
• Remove excessive print statements in CLM. Details
• Fix small indexing error in ISHMAEL MP scheme. Details
• Check the existence of WRF_CMAQ. Details
• Update REAME.namelist to include new options and missed pre-existing options.

NOTE!!!! : If downloading the files from the section below, please choose either the v4.5.tar.gz file, or the v4.5.zip file. DO NOT choose those named "Source Code." They do not include the mandatory NoahMP submodule - needed for compiling WRF.

WRF Version v4.4.2 (Bug-fix Release)

The WRF model has been updated to Version 4.4.2 on December 19, 2022.

Acknowledgements: We would like to thank Cenlin He (NCAR/RAL), Florian Sammüller (Universität Bayreuth), Adam Dury(WeatherQuest)) and Zhang Zhixiao (University of Oxford and University of Utah) for their contributions to this release.

This is a bug fix release. Following are fixes associated with this release.

Physics

• Fix a bug for mixing ratio calculation in Jarvis stomatal conductance scheme in Noah-MP. This fix affects NoahMP option OPT_CRS=2. Details
• Update urban local climate zone (LCZ) numbers in parameter tables to avoid overlap with existing NLCD land types. This update affects VEGPARM.TBL, LANDUSE.TBL, and MPTABLE.TBL. The LCZ numbers in WRF-urban are changed from 31-41 to 51-61. Details
• Fix the units and unit conversions of several variables in subroutines CARBON and CARBON_CROP (NoahMP scheme); update urban pixel identification by including LCZ urban types in module_sf_noahmpdrv.F for surface variable initialization. Details
• Refine CAPE and CIN calculations to be consistent with AMS definitions; improve LFC identification for adapting to multi-inversion layers profiles. Details
• Change the declaration of several variables in subroutine TWOSTREAM from OUT to INOUT, change the soil ice treatment in subroutine COMBINE, correct the units of three accumulated flux variables in Registry, removed the hard-coded 4 soil layers and replace it by the parameter "NSOIL". These changes only affect NoahMP land surface scheme. Details
• Change the declaration of QSFC from OUT to INOUT in sfclay and sfclayrev modules. This is because QSFC is calculated conditionally and at some grid points, it takes the input value. Details

WRFDA

• Update the VAR namelist readme to include change of use_clddet option since V4.2. Details
• Update bufrseviri.inc so that if seviri is turned on in WRFDA after Feb 2018, many error messages in the log file will be suppressed and meteosat 11 data is ingested into WRFDA to be used by the CRTM; correct the CRTM sensor information, add the HIRS4 information file to recognize NOAA 19 and not just NOAA 18 in HIRS4 and AMSUS files; update VARBC.in to include templates of NOAA 15-17 HIRS3 and NOAA 18-19 HIRS4. Details

Compiling

• Fix undefined behavior in RSL_LITE.Detail

Miscellaneous

• Add check to prevent CLM land surface scheme from being used with any urban scheme. Details

If downloading the files from the section below, please choose either the v4.4.2.tar.gz file, or the v4.4.2.zip file. DO NOT choose those named "Source Code." They do not include the mandatory NoahMP submodule - needed for compiling WRF.

WRF Version 4.4.1 (Bug-fix Release)

The WRF model was updated to Version 4.4.1 on August 25, 2021.

Acknowledgements: We would like to thank Jatin Kala (Murdoch Univeristy, Australia), Louis Marelle (LATMOS, CNRS; Paris, France), J. Shpund (PNNL), Jordan Schnell (NOAA), Robert Gilliam (US EPA), Tim Juliano and Maria Frediani (NCAR/RAL) for their contributions to this release.

This is a bug fix release. Following are fixes associated with this release.

Compiling

• A modification addresses an issue that prevented WRF from compiling when choosing either the specified move (option 2) or vortex-following (option 3) nesting options, while using an Intel compiler. This issue began with WRFV4.4. Details
• Remove duplicate reference to use module_dm in module_stoch.F (added in v4.4), which causes a compilation error when using an older version of the Intel compiler (12.1.3). Details
• Add a check for status code -4001 from Cray CCE Fortran compiler related to reading CAMtr file. Details

Physics

• Fix a minor bug for logical checking of time-varying aerosol option when climatological aerosol option selected. Details.
• Recommend not to use the full spectral bin microphysics until it is updated. Use the fast version instead. Details
• Update VEGPARM.TBL for NLCD40 landuse case to work with recent updates of the LSM initialization that reads the file. Details
• Fix a bug associated with ozone input option o3input = 0. When o3input is set to 0, ozone is effectively not used in the RRTMG radiation option before this fix. Details.

Chemistry

• Add gocart_dust dependency to mosaic_addemiss, which is necessary for WRF-CHEM to compile succeessfully. Details

If downloading the files from the section below, please choose either the v4.4.1.tar.gz file, or the v4.4.1.zip file. DO NOT choose those named "Source Code." They do not include the mandatory NoahMP submodule - needed for compiling WRF.

WRF Version 4.4

The WRF Model has been updated to Version 4.4 on April 26, 2022.

The WRF Pre-processing System (WPS) has been updated to Version 4.4.

Acknowledgements: We would like to thank Do Ngoc Khanh (Tokyo Institute of Technology), Ted Mansell (NOAA/NSSL), Joseph Olson (NOAA/GSL), Mike Iacono and John Henderson (AER), Dongmei Xu (Nanjing University of Information Science and Technology), Wen-Jou Chen,Ying-Jhen Chen, and Yi-Chuan Lo (Central Weather Bureau, Taiwan), Alexander Ukhov (KAUST), Marc Honnorat (EXWEXs), David Wong, (US EPA), Jaemo Yang (NREL), Patricia Balle (HPE), Tzu-Chin Tsai (National Taiwan University), Mathieu Le Corre (University of Toulouse, France, and University of Brest, France), Jordan Schnell (NOAA), Rebecca Schwantes (CIRES/NOAA CSL), and Prasanth Valayamkunnath, Alma Hodzic, Davide Del Vento, Masih Eghdami, Soyoung Ha, Jamie Bresch, Hugh Morrison, Craig Schwartz, Cenlin He, Rajesh Kumar, Ryan Cabell, Ju Hye Kim, Greg Thompson, Maria Frediani, Patrick Hawbecker, Timothy Juliano, and Pedro Jimenez (NCAR), and David Gill.

New in Version 4.4

Physics

• The NoahMP code has been moved to an external repository and is linked to WRF repository via a submodule. This submodule is automatically pulled in to build the code during compiling, as long as the compilation is done with internet access. If compiling without internet access, or you are not sure if the computer you are using to compile supports git (git is used during the compiling process to access code in submodule), or in the rare case that one checks out another branch, other than ‘master,’ it may be necessary to issue the following commands while connected to the internet to ensure the submodule is available for compiling.
  git clone https://github.com/wrf-model/WRF.git
  git submodule update --init --recursive
  Or in one command:
  git clone --recurse-submodule https://github.com/wrf-model/WRF.git

After this, it is okay to go offline to compile. In the case you would like to remove code in the submodule, use ‘clean -aa’ instead of ‘clean -a’. Details

• The shallow-water roughness scheme from Jiménez and Dudhia (2018) is included for offshore roughness adjustment in water depths less than 100 m and activated by namelist option shalwater_z0 = 1. The option works with a specified depth or real bathymetry input (namelist list option shalwater_depth) (Details). The bathymetry data is available from WPS/geogrid. Please acknowledge the following presentations and publications:
  [1] GEBCO Compilation Group (2021) GEBCO 2021 Grid, DOI: 10.5285/c6612cbe-50b3-0cff-e053-6c86abc09faf
  [2] Jiménez, P. A., and J. Dudhia (2018). On the need to modify the sea surface roughness formulation over shallow waters. J. App. Meteor. and Clim., 57(5), 1101-1110, DOI: 10.1175/JAMC-D-17-0137.1

• WRF-Solar is expanded to have a stochastic ensemble prediction system (WRF-Solar EPS) tailored for solar energy applications (Yang et al., 2021, Kim et al., 2022). The stochastic perturbations can be introduced into variables of six parameterizations controlling cloud and radiation processes (Details). A more detailed description of the model is provided on the WRF-Solar EPS website.
  References:
  [1] Kim, J.-H., P.A. Jimenez, M. Sengupta, J. Yang, J. Dudhia, S. Alessandrini, and Y. Xie, 2022: The WRF-Solar Ensemble Prediction System to provide solar irradiance probabilistic forecasts. IEEE J. of Photovoltaics, 12, 141-142.
  [2] Yang, J., J.-H. Kim, P.A. Jimenez, M. Sengupta, J. Dudhia, Y. Xie, A. Golnas, and R. Giering, 2021. An efficient method to identify uncertainties of WRF-Solar variables in forecasting solar irradiance using a tangent linear sensitivity analysis. Solar Energy, 220, 509-522.

• Greenhouse gas (GHG) concentrations from a number of RCPs and newer SSPs are now a default run-time option (previously they were a compile-time option). This serves two purposes: 1) Since data files provide compiled global climatological values for co2, n2o, ch4, cfc11, and cfc12, up to 2006 for RCPs and up to 2014 for SSPs, they are better estimates for historical and current runs, 2) If users have values of their own, they can be easily added to the data file. The user specifies “ghg_input=1” in the &physics namelist record for climatology, which is now the default, or “ghg_input=0” for constant values for backward compatibility. The default file used is CAMtr_volume_mixing_ratio.SSP245. A simple function for CO2 is now the default when choosing not to use the climo GHG files for RRTM - previously this function was only in RRTMG schemes. This option is only available for radiation schemes CAM, RRTMG, RRTMG-Fast, and RRTM. Details

• The option is added to output 16 accumulated physics tendencies for potential temperature, water vapor mixing ratio, and u and v components of wind. This is turned on with the namelist option “acc_phy_tend=1” in &physics. Details

Other New Options

• The capability to couple WRF and CMAQ (an air quality model developed at the US EPA) is added. As a coupled model, WRF-CMAQ can be run in a one-way fashion (i.e., meteorological information will be transferred to CMAQ directly to drive its calculation), or in a two-way fashion, (i.e., the aerosol information from CMAQ will be fed back to the RRTMG radiation physics in WRF). This is available beginning in WRFV4.4 and CMAQ v5.3.3.3. Refer to the EPA’s WRF-CMAQ Model webpage for instructions. Details

• The ability to write compressed NetCDF4 files in parallel, via NetCDF V4.7.4 (and later) is added. Performance is slower than pnetcdf, but can be notably faster than regular NetCDF on parallel file systems. As expected, compression provides files significantly smaller than pnetcdf generates. Details

Improvements and Bug Fixes

Physics

Microphysics

• Thompson Aerosol-aware microphysics: Code enhancements are introduced to the processing of aerosol information in real.exe; specifically, legacy code to support the old format aerosol data before 3.9 is removed and logic in the real program is improved. Details

• Thompson Aerosol-aware microphysics: A black carbon aerosol category is added. To include black carbon in this microphysics as well as its radiative effect, an updated data file, QNWFA_QNIFA_QNBCA_SIGMA_MONTHLY.dat, is required and set wif_input_opt = 2 (option 1 works with water/ice friendly aerosol data only). Support is also added for ingesting real-time data that contains these aerosols (such as from GEOS-5) by setting use_rap_aero_icbc = .true. (Details). Time-varying surface aerosol emission from either climatology or real-time data is now handled using namelist option qna_update = 1 with input file name wrfqnainp_d0* (must set auxinput17_interval and io_form_auxinput17). In addition, biomass burning organic and black carbon aerosols can be added to the model by setting namelist wif_fire_emit = .true.. This option will work with data with and without black carbon, but it is particularly important during active wildfire hence when using a first-guess aerosol source that has information about biomass burning emissions (e.g., GEOS-5). When using this option, it is assumed this aerosol is evenly distributed in the PBL (controlled by namelist wif_fire_inj = 1). Details

• Thompson microphysics: An update to this, plus the cloud-fraction scheme “icloud=3” to better match observations. Modifications include updates to RRTMG LW and SW, and RRTMG fast LW and SW. Details

• P3 microphysics: Four options (50, 51, 52, and 53) of the P3 scheme are updated. The 3-moment lookup table file size is reduced by an order of magnitude (file names are changed for the lookup tables). Improved flexibility has been added by including the Kogan (2013, JAS) option for cloud autoconversion/accretion. A few minor bug fixes to harden the code have been added (Details).
  References:
  [1] Morrison, H., and J. A. Milbrandt, 2015: Parameterization of cloud microphysics based on the prediction of bulk particle properties. Part 1: Scheme description and idealized tests. J. Atmos. Sci., 72, 287-311.
  [2] Milbrandt, J. A., and H. Morrison, 2016: Parameterization of cloud microphysics based on the prediction of bulk particle properties. Part 3: Introduction to multiple free categories. J. Atmos. Sci., 73, 975-995.
  [3] Milbrandt, J. A., H. Morrison, D. T. Dawson II, and M. Paukert, 2021: A triple-moment representation of ice in the Predicted Particle Properties (P3) microphysics scheme. J. Atmos. Sci., 439-458.

• NTU microphysics: Fixed uninitialized variable BHTMP. Details.

• NSSL microphysics: Fixed a few uninitialized variables. Details

Radiation

• A new cloud overlap option is available for RRTMG radiation schemes. The option is set by using the exponential-random namelist parameter “cldovrlp=5.” A decorrelation length option, “idcor,” is also added. It can be set as a fixed value at 2500 m (idcor=0), or a func...

WRF Version 4.3.3 (Bug-fix Release)

The WRF model has been updated to Version 4.3.3 on January 11, 2022.

This is a bug fix release. Following are fixes associated with this release.

Physics

• The v4.3.2 release contained an error in the commit that addressed the situation of segmentation faults when running a PBL on a coarse grid and no PBL on the fine grid. If a user is running the option to get the time series output, then the model will always report that there are PBL + LES issues if the user is choosing the MYNN or EEPS PBL schemes. This bug is fixed in the v4.3.3 release.

Chemistry

• For WRF Chem, ISORROPIA in chem_opts = 100,108,109 is now controlled by a logical namelist option do_isorropia
• Output photolysis rates for NO2 and O1D are included in history stream by default
• An indexing bug that incorrectly enhanced vertical mixing at the surface layer in the WRF Chem dry_dep_driver.F filei is fixed.

WRF Version 4.3.2 (Bug-fix Release)

The WRF model has been updated to Version 4.3.2 on 14 December, 2021.

Acknowledgements: We would like to thank Patricia Balle (HPE), Jamie Bresch (NCAR), Jordan Schnell (NOAA), Yaping Shao (Universität zu Köln), Martina Klose (Karlsruhe Institute of Technology), Piotr Kasprzyk (IETU Katowice), Theodore M. Giannaros (National Observatory of Athens, Greece)

This is a bug fix release. Following are fixes associated with this release.

Compiling

• Added a new stanza that is only for ARM processors (right now aarch64 and armv7l) with GNU.

Physics

• Added time-varying greenhouse gases to RRTMG shortwave options: RRTMG and RRTMG-fast.
• A test was introduced to stop the incorrect combination of particular PBL schemes on coarser grids with the LES PBL option selected on a finer grid. Previously, this problem caused an inconsistent number of variables on the CG and FG, which caused segmentation faults when trying to do feedback or advection of unavailable fields.
• A few syntax errors in NSSL, NTU, an NoahMP were fixed. Most compilers skipped over them. Either "small impact" or "no impact" for users for whom the code already compiled.

WRF-Chem

• In WRF Chem, remove photolysis rates from the default history stream (these photolysis rates are not used by most modules).

WRF-fire

• Bug fix for fire module related to the initialization of 1000-h fuel moisture content due to an incorrect indexing assignment from the namelist entries for fuel classes.

Registry

• Starting with release-v4.3, the CLM specific variable PCT_PFT appeared in the standard wrfout file, even when the CLM option was not selected. A small modification to the standard Registry file removed this incorrectly output 3d array. Other than removing this innocuous zero-valued 3d array from the output stream, there is no other impact for users.

Miscellaneous

• A fatal error in the real program is now issued when a user requests lateral boundary topography smoothing, but lacks the first-guess soil elevation data to do the weighted averaging of topography. Previously, this discrepancy was ignored, and the d01 high-resolution elevation data was quietly left undisturbed. We have seen this problem when a user chooses to initialize the model with ERA5 data, but when insufficient time invariant files are used.

v4.3.1: WRF Model Version 4.3.1 Release

The WRF model has been updated to Version 4.3.1 on October 28, 2021.

Acknowledgements: We would like to thank Jesus Fernandez (Instituto de Fisica de Cantabria CSIC-UC, Santander, Spain), Andrea Zonato (University of Trento), ed Mansell (NOAA/National Severe Storms Lab), Hugh Morrison (NCAR), Matthias Demuzere (Ruhr University Bochum) and Piotr Kasprzyk (IETU Katowice) for their contributions to this release.

This is a bug fix release. Following are fixes associated with this release.

Compiling

• module_ra_eclipse.o is added to radiation driver's dependency list to avoid occasional compilation failures.

Physics

• Bug fix in Noah LSM routine to initialize several local variables. Without their initialization, the same case run with different number of processors cannot yield identical results.
• Fix in initialization for rand_perturb=1 option for the stochastic capabilities. The error is caused by an incorrect argument list.
• New CAMtr_volume_mixing_ratio data files for CMIP6 SSPs are added to acount for yearly global average concentrations from input4MIPs (v1.2.0 for historical part and v1.2.1 for scenario evolution).
• The photovoltaic panel (PVP) parameterization scheme, new in version 4.3, has been updated, since the previous one provided unreasonable results due to wrong calculation of the radiation balance. While before a simple energy balance was adopted to calculate the PVP temperature and related heat fluxes, now a prognostic equation is solved, accounting for the thermal coefficients of the photovoltaic panels.
• For the NSSL 2 moment MP scheme (mp_physics=17, 18, and 22), the formulation of snow radar reflectivity is reverted back to version (pre-4.1.3) using size-dependent snow density. The diagnosed bright band is still turned on by default: iusewetsnow=1. (Setting iusewetsnow=3 will switch back to old formulation.)
• Fix an initialization problem in Thompson scheme (mp=28). Since V4.0 the aerosol aware Thompson (mp=28) option has not been initializing the surface aerosol source array consistently between a parent and nested domain due to grid-size dependence. This has been removed and the results will change if dx is not 20 km, but now nests will have the same source.
• An error in longwave radiation calculation in the BEP-BEM urban module is fixed. This error affects the calculation of TSK, which now is correctly calculated.
• The P3 microphysics scheme is updated with bug fixes and code cleanup.
• Units specified in Registry are corrected for several NTU microphysics variables.
• Dimensional errors in subroutine spec_bdytend_perburb and spec_bdytend_perturb_chem are fixed (in module_bc.F). This routine is used to perturb fields on the model lateral boundaries for stochastic processing, and only affects results if perturb_bdy or perturb_chem_bdy are not 0 and they are 0 by default.
• Some of the urban parameter values for LCZ are changed to make them more generic.

Data Assimilation

• Logical variable got_var_sso is added to the history file for cycling DA application for use with the topo_wind option.

Registry

• A temporary fix has been put in place for the moving nest capability when using the Intel compiler. Previously, the WRF source code did not build due to a segmentation fault in the execution of the tools/registry program.

Miscellaneous

• Increase total time periods available to process for climate simulations. The restriction of 10000 time periods in a single file has been increased to 60000 (a value that allows 3-hourly data for 20 years).
• Revert print and when to turn on damping to pre 4.3 code. In WRFV4.3, w_damping is turned on at CFL = 1.2, and CFL is printed when it exceeds 1.2. This results in many CFL prints. In the release of WRFV4.3.1, w_damping starts at CFL = 1.0, and CFL prints appear when CFL exceeds 2.0. When IEVA is on, w_damping starts at CFL = w_crit_cfl set in the namelist, and CFL prints only appear for those exceeding 2.0.
• The description of option MAD-WRF is improved