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

WRF Version 4.3

The WRF Model has been updated to Version 4.3 on May 10, 2021.

Acknowledgements: We would like to thank Matthias Göbel (University of Innsbruck), Jaemo Yang and Yu Xie (NREL), Will Hatheway, Douglas Lowe (University of Manchester), Ted Mansell and Louis Wicker (NOAA/NSSL), Sam Elliott (TQI), Megan Bela and Stu McKeen (CU Boulder CIRES/NOAA CSL), Xinzhong Liang (University of Maryland), Tzu-Chin Tsai and Jen-Ping Chen (National Taiwan University), Robert Gilliam and Jonathan Pleim (US EPA), Alexander Ukhov (KAUST), Zhixiao Zhang (University of Utah), Adam Varble (PNNL and University of Utah), Katelyn Barber and Brian Gaudet (PNNL), Robert Arthur, Katie Lundquist, and Jeff Mirocha (LLNL), Sam Levis (SLevis Consulting), Andrea Zonato (University of Trento, Italy), Michael Toy (NOAA/GSL), Chunxi Zhang (NCEP) and Yuqing Wang (University of Hawaii), Eric A. Hendricks (NCAR/NSAP), James Ruppert (Penn State University), Isaac Rowe (University of Kentucky), Alex Montornès (University of Barcelona), Yunyao Li and Xin-Liang Zhong (University of Maryland), Jan Mandel (University of Colorado, Denver), Stacy Walters (formerly NCAR), Luke Conibear (University of Leeds), Sonia Lasher-Trapp (University of Illinois), T. Iguchi (NASA/Goddard), Wei Sun (Chinese Academy of Sciences), Greg Thompson (JCSDA), Prasanth Valayamkunnath, Pedro Jimenez, Jamie Bresch, Craig Schwartz, Jim Bresch, Cenlin He, Hugh Morrison, Masih Eghdami, Timothy W. Juliano, Negin Sobhani, Dave Lawrence, Bill Sacks, Jared Lee, Laura Fowler, and Mary Barth (NCAR)

Note: WRF v4.3 is the last release of the WRF model that will support the NMM dynamical core and HWRF capability. Beginning with WRF v4.3.1 and with all subsequent releases, the NMM and HWRF capabilities will incrementally be removed from the model source code.

New in Version 4.3

Physics

• A turbulence kinetic energy (TKE) and TKE dissipation rate (ε) based 1.5-order closure PBL parameterization (E–ε, EEPS) is added (Zhang et al. 2020, MWR). Works with surface layer options, 1, 91, and 5.

• An updated version of P3 now includes a one-ice category, 3-moment ice option. Milbrandt et al. (2021) [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., 78(2), 439-458, https://doi.org/10.1175/JAS-D-20-0084.1]

• The NTU (National Taiwan University) scheme (mp_physics = 56). It applies double moments for the liquid-phase and triple moments for the ice-phase hydrometeors together with the consideration for ice crystal shape and density variations. There are five major features to NTU scheme: condensation nuclei (CN) and ice nuclei (IN) are tracked separately for the processes of cloud/rain activation and ice deposition-nucleation using predicted supersaturation; applying the triple-moment (the zeroth, second, and third moments) closure method to describe the evolution of ice particle’s spectrum; solid-phase hydrometeors’ classification (pristine ice, snow aggregate, rimed ice, and hailstone) is redefined according to their key formation mechanisms; ice crystals’ shape and apparent density can evolve gradually according to the growth conditions; and fall speed of each moment for frozen particles depends on shape and density.

  For the detailed parameterizations in the NTU scheme, the liquid-based formulae of the bulk conversion rates are adopted from [1], and the technique for aerosol activation to rain/cloud is introduced in [2] and [3]. The triple-moment approach, representation of ice properties, mixed- and solid-based equation/kernels are illustrated in [4] and [5].

  References:
  [1] Chen, J.-P. and S.-T. Liu, 2004: Physically based two-moment bulkwater parameterization for warm-cloud microphysics. Quart. J. Roy. Meteor. Soc., 130, 51–78, doi:10.1256/qj.03.41.
  [2] Cheng, C.-T., W.-C. Wang, and J.-P. Chen, 2007: A modeling study of aerosol impacts on cloud microphysics and radiative properties. Quart. J. Roy. Meteor. Soc., 133, 283–297, doi:10.1002/qj.25.
  [3] Cheng, C.-T., W.-C. Wang, and J.-P. Chen, 2010: Simulation of the effects of increasing cloud condensation nuclei on mixed-phase clouds and precipitation of a front system. Atmos. Res., 96, 461–476, doi:10.1016/j.atmosres.2010.02.005.
  [4] Chen, J.-P. and T.-C. Tsai, 2016: Triple-moment modal parameterization for the adaptive growth habit of pristine ice crystals. J. Atmos. Sci., 73, 2105-2122, doi:10.1175/JAS-D-15-0220.1.
  [5] Tsai, T.-C. and J.-P. Chen, 2020: Multi-moment ice bulk microphysics scheme with consideration for particle shape and apparent density. Part I: Methodology and idealized simulation. J. Atmos. Sci., 77, 1821–1850, doi:10.1175/JAS-D-19-0125.1.

• Added a new option (ra_sw_eclipse) to model the effect of eclipses based on the Bessel's method in four radiation schemes: RRTMG, Dudhia, Goddard, and old Goddard. Additional output includes the location of the eclipse: ELAT_TRACK and ELON_TRACK. For reference, see this paper: Montornès, A., Codina, B., Zack, J. W., and Sola, Y.: Implementation of Bessel's method for solar eclipses prediction in the WRF-ARW model, Atmos. Chem. Phys., 16, 5949–5967, https://doi.org/10.5194/acp-16-5949-2016, 2016.

• A new orographic gravity wave drag option is added (gwd_opt = 3). The scheme includes large-scale orographic gravity wave drag in a similar way as in gwd_opt = 1. In addition, two subgrid-scale sources of orographic drag are added in this option. The additional schemes are applicable at coarse horizontal grid resolution (~100s km) down to fine resolutions on the order of 1km, and they account for small-scale ~1km topographic variations. Setting namelist option gwd_diags = 1 (default is "0") causes diagnostic data to be output to the wrfout_d0x files. The data include: 1) 2D vertically integrated momentum fluxes, i.e., surface stress, DUSFC_xx (x-direction) and DVSFC_xx (y-direction), where xx={LS,BL,SS,FD}, which are "large-scale", "blocking", "small-scale" and "form drag" contributions, respectively; and 2) 3D drag forces DTAUX3D_xx (x-direction) and DTAUY3D_xx (y-direction), where xx={LS,BL,SS,FD}. This scheme is contributed by NOAA/GSL.

• The multilayer BEP (Building Effects Parameterization) and BEP+BEM (BEP with the Building Energy Model) urban canopy models (UCMs) are added to the Yonsei University (YSU) planetary boundary layer parameterization. Reference: Hendricks, E. A., J. C. Knievel, and Y. Wang, 2020: Addition of multilayer urban canopy models to a nonlocal planetary boundary layer parameterization and evaluation using ideal and real cases, J. Appl. Met. Clim., 59, 1369-1392.

• Implementation of Local Climate Zone (LCZ using WUDAPT (31-41) landuse classes, along with standard urban classes (31-33). (Ref: Stewart, I.D. and Oke, T.R. (2012) Local Climate Zones for Urban Temperature Studies. Bulletin of the American Meteorological Society, 93, 1879-1900. http://dx.doi.org/10.1175/BAMS-D-11-00019.1). More information can be found at https://ral.ucar.edu/sites/default/files/public/product-tool/urban-canopy-model/WRF_urban_update_Readme_file_WRF4.3.pdf. Data from https://www.wudapt.org/ is required. Note that the parameters in the new urban table, URBPARM_LCZ.TBL, may vary greatly from city to city. The default values are probably not appropriate for any given city. Users should adapt these values based on the city they are working with.

• WRF-urban updates for green roof, solar panel, and new building drag coefficient for BEP+BEM. The paper describing the green roof update is under development. The new building drag coefficient is based on Santiago and Martilli (2010) and Gutierrez et al. (2015).
  [1] Santiago, J. L. and Martilli, A. (2010). A Dynamic Urban Canopy Parameterization for Mesoscale Models Based on Computational Fluid Dynamics Reynolds-Averaged Navier-Stokes Microscale Simulations. Boundary-Layer Meteorology, 137(3):417-439.
  [2] Gutí errez. E., Martilli, A., Santiago, J. L., and González, J. E. (2015). A Mechanical Drag Coefficient Formulation and Urban Canopy Parameter Assimilation Technique for Complex Urban Environments. Boundary-Layer Meteorology, 157(2):333-341.
  [3] A. Zonato, A. Martilli, E. Gutierrez, F. Chen, C. He, M. Barlage, D. Zardi, and L. Giovannini (2021): Exploring the effects of rooftop mitigation strategies on urban temperatures and energy consumption, Atmospheric Chemistry and Physics (under review).

• A new dynamic irrigation scheme is implemented in NoahMP to estimate irrigation water requirements and apply water in the irrigated croplands. This new scheme irrigates the croplands based on sprinkler, micro, or surface flooding methods. The various options are selected from the namelist, and are described in the run/README.namelist file.

• The capability to couple Community Terrestrial Systems Model (CTSM) with WRF via LIghtweight Land Atmosphere Coupler (LILAC) is added and activated by setting namelist option sf_surface_physics to 6. This is the initial beta release of WRF-CTSM coupling capability. For instructions on how to run WRF with CTSM please check instructions on using CTSM with WRF. See the WRF-CTSM User’s Guide (https://escomp.github.io/ctsm-docs/versions/master/html/lilac/specific-atm-models/wrf.html). Questions regarding this capability can be addressed to the CTSM Forum (https://bb.cgd.ucar.edu/cesm/forums/ctsm-clm-mosart-rtm.134/).

Other New Options

• The Implicit-Explicit Vertical Advection (IEVA) scheme has been implemented that permits a larger time step by partitioning the vertical transport into an explicit piece, which uses the normal vertical schemes present in WRF, and an implicit piece which uses implicit transport (which is unconditionally stable). The combined scheme permits a larger time step than has previously been used, and reduces w-filtering. The scheme will be useful for CONUS-scale CAM ...

WRF Version 4.2.2

The WRF model has been updated to Version 4.2.2 on January 15, 2021.

Acknowledgements: We would like to thank Calvin Howes (UCLA), Richard Easter (PNNL), Robert Arthur and Jeff Mirocha (LLNL), Matthias Göbel (University of Innsbruck), Stacy Walters (formerly NCAR), Ryan Cabell (NCAR), Soonyoung Roh and Hwan-Jin Song (National Institute of Meteorological Science, Korea), Arianna Valmassoi (Uni-Bonn), Ted Mansell (NOAA/NuSL), Marc Honnorat (EXWEXs), Lukas Pilz (Heidelberg University), Timothy W. Juliano, Ju-Hye Kim, Pedro A. Jimenez, Jared Lee, Thomas Brummet (NCAR/RAL), Tim Raupach (UNSW CCRC) for their contributions to this release.

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

Compiling

• Changes are made so that WRF-Hydro can be built successfully with the INTEL (ifort/icc)
• New features are added to the WRF code so that the model can be built on a Raspberry Pi with the GNU/8 compiler.
• Due to subroutine and function argument inconsistencies, the WRF code will not compile with gfortran/10. The fix introduces a new compiler flag for all gfortran stanzas (-fallow-argument-mismatch -fallow-invalid-boz).

Dynamics

• To close the dry theta budget at the lowest grid point when use_theta_m is enabled, the surface heat fluxes, and in the case of km_opt=5 also the non-local heat flux, are multiplied with 1+Rv/Rd*qv. This should be done only for qv at the surface.
• Fix incorrect index limits asscoiated with advection. When using advection order < 5, and either open or specified boundary conditions, the upper limit of the indexing in the horizontal advection loops of geopotential was previously incorrect. For horizontal advection order >= 5, the index limits also were incorrect.
• Missing corner points are set when setting boundary conditions of 3D variables and all staggered variables are treated equally in symmetric BC. Thereby the periodic BC become cleaner and more consistent with set_physical_bc2d, which leads to correct BC for SGS momentum fluxes at the northern boundaries.
• Fix divide-by-zero errors in the km_opt=5 option.
• Bug fix in the ideal case initialization routines, in which incorrect indices were used in the calculation of ph_1 after a perturbation bubble was added. For the idealized cases that do not use the hybrid vertical coordinate by default, there is no impact at all.

Physics

• Bug fix to use correct rho value in cal_titau subroutines. In the cal_titau subroutines in module_diffusion_em, rho was not always interpolated to the correct location on the staggered grid. A rhoavg variable was added to cal_titau_12_21, cal_titau_13_31, and cal_titau_23_32 and used instead of the cell-centered rho variable.
• Bug fix to correctly calcuate surface downward diagnostic output of long- and short-wave fluxes and correct two wrong numerical values used in the code. This bug fix only affects RRTMG-K radiation option.
• Fix incorrect parentheses in weighted average for QSFC when sea-ice fraction is used in myjsfc_seaice_wrapper and qnsesfc_seaice_wrapper.
• Correct the tke seed value to be non-zero if and only if the surface heat and momentum fluxes are zero.
• Bug fix for temporal selection that spans across different years and different local days. This fix affects the irrigation scheme. Previously, the irrigation schemes weren't working when the date selection was across two different years.
• A minor fix to avoid occasional instabilities in the surface layer option 1.
• Bug fix to account for the effective radius of the unresolved hydrometeors by FARMS. The fix is valid for WSM6, Thompson and all other microphysics options that do not provide effective radius.
• Bug fixes for the channel method to ensure that the water used for irrigation in the channel method can be passed to the land surface model.
• Several fixes are introduced to the Deng's shallow cumulus parameterization: add no resolved hydrometeors to the unresolved ones to avoid double counting; remove clouds if the updraft is not active; correct conversion factor for precipitation; correct initialization of radiusc variable; limit variable NT to avoid array out of bounds.
• Incorporate specific-crop parameters for photosynthesis and stomata subroutine in Noah-MP-Crop. The current release WRF-Crop option 1 uses generic-crop parameters in stomata subroutine to calculate photosynthesis and stomata resistance, regardless of crop type. Also some crop parameters in MPTABLE.TBL for corn and soybean are not consistent with the values used in the publication. This update fixes these parameter values in the crop parameter section in MPTABLE.TBL, as well as adds specific-crop photosynthesis-stomata parameters to this section.

Data Assimilation

• Bug fix for WRFDA incorrect application of errfac.dat at each outer loop when use_obs_errfac=true and max_ext_its > 1.
• Big fix for WRFDA incorrect ensemble perturbation values for qice, qsnow and qgraup when alpha_hydrometeors=true and ep_format=2.

Chemistry

• Fix improper indexing in a conversion factor, which caused addressing (seg fault) or floating point errors when using aircraft emissions for WRF Chem. This has been corrected by matching the indexing on the LHS with the RHS.
• Fix a namelist option incompatibility between chem_opt (16) and gas_drydep_opt (1) , which leads to trying to access a variable that is not available in memory. A fatal error was added when the Wesely scheme initialization is called with numgas = 0.

Diagnostics

• Fix lh_urb2d diagnostic to be urban area average instead of grid cell average consistent with other urb2d diagnostics associated with NoahMP. No effect on run results.
• Fix mixactivate for diagnostic CCN in sectional schemes. This fix impacts Morrison and Lin et al. microphysics schemes.
• Correct solar zenith angle calculation and check presence of hydrometeor type before calculating cloud parameters for the solar diagnostic package. In addition, shortwave irradiance variables were added to the tslist when activating the RRTMG or RRTMG FAST shortwave radiation scheme or FARMS.

Registry

• Fix the problem of non-reproducibility due to the advection order. Previously, the halo exchange (used during distributed memory communication) had inconsistent use of h_mom_adv_order. Consequently, the model results were not bit-identical with different number of processors (when the advection order differed between the momentum and scalar variables).

Miscellaneous

• Fix an inconsistency in the declaration of integer kinds in the routine that processes binary formatted data.
• Examples.namelist is modified to provide sufficient information for trajectory run.
• Bug fix to make the stand-alone vertical interpolation program to work properly. This utility is only used for internal testing and thus has no impact on users.
• An MPI barrier is added at the end of wrf_dm_initialize to force all of the processes to be synchronized before checking the namelist consistency. This barrier avoids occasional crash in setup_physics_suite (in share/module_check_a_mundo.F) when running real.exe.
• Remove or fix some obsolescent and non-standard features in several physics modules which were preventing WRF to be built with IBM XL v16.1.1 on Power9.

WRF Version 4.2.1

The WRF model has been updated to Version 4.2.1 on July 22, 2020.

Acknowledgements: We would like to thank John Collins (Edge Hill University), James Ruppert (Penn State University), Nicolas Baldeck (OpenMeteoData),Cristina L. Archer (University of Delaware), Sicheng Wu and Yulong Ma (University of Delaware, CReW), and Pedro A. Jimenez (NCAR/RAL), Franciano Puhales (Federal University of Santa Maria, Brazil), Ted Mansell (NSSL), Manuel Luis Aznar (University of La Laguna), Isaac Rowe (University of Kentucky), Matthias Göbel (University of Innsbruck), Matthias Göbel (University of Innsbruck), Yulong Ma (University of Delaware), Christopher Thomas (Climate Change Research Centre, UNSW Australia), Michael Newman (Woodard & Curran), Bart Brashers (Ramboll), Peng Zimu (Peking University) for their contributions to this release.

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

Compiling

• Changes are made to implement static analysis regression testing of WRF (#1252, #1253))
• A compiler error raised by ifort 13 for a fire module routine due to omission of the keyword "SUBROUTINE" in the "END SUBROUTINE" statement has been addressed. (#1223)
• A minor modification has been introduced into the SBM Polar Radar microphysics code to allow the WRF code to build with PGI compilers. The nonstandard derf() intrinsic has been replaced by the 2008 standard compliant erf() intrinsic.(#1183, #1246)
• The non-standard spacing in macro is removed, which makes the WRF system able to be built with LLVM clang. (#1221)

Dynamics

• Fix the 1D advection testing program broken with the hybrid vertical coordinate. (#1247)
• For periodic boundary conditions, the slope calculation for the lateral boundaries is made equivalent to the calculation for the interior of the domain (#1217)
• Fixed units of surface momentum flux in dyn_em/module_diffusion_em.F when using m_opt. This bug fix divides the surface fluxes by the density to obtain the correct units. This change only affects the output of the SGS fluxes (nba_mij). The tendencies and thus the results are not changed.

Physics

• Fix a problem in the advection of TKE generated by the wind turbines if the user instructs MYNN to advect the TKE (setting mynn_tkeadvect = .true. for each domain). There is also an empirical reduction of the wind turbines' TKE coefficient based on LES results (Archer et al. 2020). (#1235). Note that TKE generated by the wind turbines was advected in WRF V3.3 - V3.4. In WRF V3.5, the TKE was advected if mynn_tkeadvect option is on. The error was introduced in WRF V3.6 when the wind turbine scheme was significantly updated.
• Fix a divided by zero problem in Shin-Hong PBL (#1219)
• Fix an error in aer_opt =2 and Goddard SW radiation to fill in the 2D arrays with the aerosol optical properties (SSA and g) from namelist.input. (#1190)
• Fix a floating point log(0) for the NSSL microphysics. Also, minor changes are made to lookup table. (#1216)
• Fix a bug in RRTMK radiation shceme. This bug leads to the output shortwave and longwave tendencies being in swapped positions. However, note that this bug does not affect the sum of shortwave and longwave heat tendency, so it does not affect model results (#1257).

Data Assimilation

• Fix a problem related to VarBC when num_fgat_time > 1 (#1222)

Chemistry

• Enable TUV diagnostics only for debugging (debug_level >=100). This is because when using WRF-Chem with the new Photolysis option (phot_opt = 4) activated, the model spent too much time on looping and writing the TUV.diags which is only used for debugging photolysis rates.

Diagnostics

• Fix the segmentation fault problem when time series is output with the solar diagnostic option activated (#1228)
• Fix occasionally incorrect calculation of the times of minimum and maximum of fields within the clWRF diagnostics module (#1208)

Registry

• The urban module caused segmentation fault when building WRF with real*8, which was traced to a default assignment to the wrong horizontal interpolation and feedback routines. This problem is fixed. (#1213)

Miscellaneous

• README.grid_fdda and examples.namelist are modified for correct setting of rinblw when observational nudging is applied to nested domains. (#1248)

WRF Version 4.2

The WRF Model has been updated to Version 4.2 on April 23, 2020.

The WRF Pre-processing System (WPS) has been updated to Version 4.2.

Acknowledgements: We would like to thank Tieh-Yong Koh, Ricardo Fonseca, and Tengfei Zhang (Earth Observatory of Singapore, Nanyang Technological University, Singapore), Chee-Kiat Teo (Temasek Laboratories, Nanyang Technological University, Singapore), Kiran Alapaty and Rob Gilliam (EPA), Robert Arthur, Katie Lundquist (LLNL), Tina Chow and Jason Simon (U.C. Berkeley), Jacob Shpund, Alexander Khain, and Barry Lynn (The Hebrew University, Jerusalem, Israel), Arianna Valmassoi (University College Dublin/NCAR), Jan Mandel and Angel Farguell (University of Colorado Denver), Adam Kochanski (University of Utah), Anders Jensen, Changhai Liu, Greg Thompson, Ju Hye Kim, Pedro A. Jimenez, and Timothy Juliano (NCAR/RAL), Milan Curcic (University of Miami), Negin Sobhani and William Sacks (NCAR/CISL), Mike Iacono (AER), Yago Riveiro (Air Quality and Odor Management), Brian Reen (Army Research Laboratory), Piotr Kasprzyk (CIRI), Robert Rozumalski (COMET), Theodoros Christoudias (Cyprus Institute), Emily Collier (FAU Erlangen-Nürnberg), Han Lang (Fujitsu America, Inc.), Kezhen Chong (Georgia Institute of Technology), Huang Wei (HPE), Thomas Auligné (JCSDA), Alexander Ukhov (KAUST), Sooya Bae (KIAPS), Kyo-Sun Lim (Kyungpook National University), Hugh Morrison, Jamie Bresch, Jim Bresch, Judith Berner, Kevin Manning, Michael Duda, and Yali Wu (NCAR/MMM), Michael Kavulich (NCAR/DTC), Stacy Walters (NCAR/ACOM), James Kenyon (NOAA/CIRES), Joseph Olson, Ravan Ahmadov, and Tanya Smirnova (NOAA), Yu Xie (NREL), Ted Mansell (NSSL), Dongmei Xu (NUIST/NCAR), Shizhang Wang, Xin Zhang, and Feng Gao (NUIST), Daniel Wesloh (Penn State University), Xu Zhang (Shanghai Typhoon Institute/CMA, China), Rob Fovell (SUNY Albany), Ivan Toman (University of Zadar, Croatia), Maik Reichert, Richard Carpenter, and Tao Sun (NUIST).

New in Version 4.2

Physics

Planetary Boundary Layer

• A three dimensional scale-adaptive TKE subgrid mixing parameterization scheme (SMS-3DTKE, km_opt=5) developed by Shanghai Meteorological Service (SMS), China. (Zhang, X., Bao, J., Chen, B., and Grell, E., 2018: A Three-Dimensional Scale-Adaptive Turbulent Kinetic Energy Scheme in the WRF-ARW Model. Mon. Wea. Rev., 146(7), 2023-2045, https://doi.org/10.1175/MWR-D-17-0356.1) . The subgrid mixing parameterization extends the original TKE model (km_opt=2, Deardorff 1980) that is usually used as an LES subgrid model to the mesoscale limit in the framework of the WRF-ARW. The scheme can be used in LES, mesoscale and the gray zone resolutions in between. The option must be used with diff_opt=2. The scheme can replace LES subgrid model (km_opt=2) and conventional PBL schemes. When the scheme is turned on (diff_opt=2 and km_opt=5), PBL schemes must be turned off (bl_pbl_physics = 0). This scheme can be used with sf_sfclay_physics = 1, 5, 91. (Thanks to Xu Zhang of SMS, CMA, China)

Surface Irrigation

• Three surface irrigation options (Valmassoi et al., 2020, Geosci. Model Dev., to be published) are added to the Noah LSM to parameterize irrigation as a function of three evaporative processes that the water applied undergoes. The irrigation water can evaporate (i) from the surface (Channel method), (ii) from the canopy and then drip on the surface (Drip method), or (iii) from the atmospheric lowest mass-model layer (Sprinkler method) and then follow the previous process. The schemes have an explicit treatment regarding the water amount, location, and timing. (Thanks to Arianna Valmassoi (University College Dublin/NCAR.)

Radiation

• A new parameterization, FARMS (Fast All-sky Radiation Model for Solar applications, Xie et al., 2016, Solar Energy), provides fast calculation of the surface shortwave irradiance allowing the WRF model to call the scheme every model time step, resulting in an irradiance that responds to changing clouds. The scheme is activated by setting swint_opt = 2 in the WRF namelist.input file and is added to complete the WRF-Solar suite (Jimenez et al., 2016, Bull. Amer. Meteor. Soc.). (Thanks to Yu Xie of NREL, and P. Jimenez of NCAR/RAL)

Other New Options

• A new diagnostic package for users with interests in parameters that are potentially relevant to solar applications is added. In the new package, The following variables are calculated: solar zenith angle, clearness index, 2-D max cloud fraction, water vapor path, liquid water path, ice water path, snow water path, total water path (liquid + ice + snow), liquid cloud effective radius, ice effective radius, snow effective radius, liquid cloud optical thickness, ice optical thickness, snow optical thickness, cloud base height, and cloud top height. Also, for liquid and ice variables, the 'total' water path, effective radius, and optical thickness are computed, where the 'total' variables also account for subgrid (unresolved) hydrometeors. The diagnostics is activated by namelist variable solar_diagnostics (=1) in namelist record @Diags. (Thanks to Timothy Juliano, Pedro Jimenez, and Ju-Hye Kim of NCAR/RAL)

• Introducing a Windows-based WRF build and run via the free Unix-like CYGWIN environment. (Thanks to Daniel Wesloh of The Pennsylvania State University Department of Meteorology and Atmospheric Science)

Improvements and Bug Fixes

Physics

Microphysics

• Updates to the Thompson MP scheme:
  A significant alteration is introduced for diagnosing the Y-intercept parameter for the one-moment graupel. These changes affect results for any graupel area. The changes are based on observations of graupel/hail size spectra from aircraft observations. The older diagnosis used an inverse relationship for N0 as a function of graupel mass mixing ratio (Qg) plus a functional dependence on supercooled liquid water (to approximate favorable wet growth). A recent analysis of T-28 aircraft-observed data by Field et al. (2019) shows observations in direct contradiction; particularly that N0 is more directly (not inversely) proportional to Qg. After 5 slight modifications to the constants in the formula, this change produces the best match to observed radar reflectivities, particularly with the upper tail of the distribution.

• Updates to the Fast (33 bins) Spectral-bin Microphysics (FSBM):

  • The update includes: A switch to use either graupel or hail; Cloud base nucleation; 3 log-normal user-defined aerosol distribution; Updated collision-coalescence; spontaneous rain and snow breakup; and code structure changes.
  • A forward polarimetric operator is coupled to the FSBM scheme. The user can see the total reflectivity field, as well as the per hydrometeor total reflectivity (rain, snow, graupel/hail). This can be activated by the namelist option sbm_diagnostics = 1 in &physics.
  • In order to run the new FSBM scheme, users need to download an external directory named "SBM_input_33" consisting of mandatory input tables and place it in the 'run' directory. In case the coupled polarimetric forward operator is to be used (e.g., 'sbm_diagnostics = 1'), a second directory consisting of scattering amplitudes named "SBM_scatter_amplit.tgz" needs to be placed in the 'run' directory. Both directories are compressed and can be downloaded at the following link: https://www2.mmm.ucar.edu/wrf/src/wrf_files/
  • When using SBM Fast microphysics scheme and simulating deep continental convective systems (as opposed to maritime convection), it is advised to use a 43-bins version of the updated FSBM scheme. In order to run the code using 43 bins, one needs to modify: 1) The registry (to include more bins for the advection), 2) the corresponding loop indices inside the scheme, and the bin-space parameter (NKR) placed at the top of the main module, and 3) switch between the 33-bins input tables with 43-bins.
  • The FAST SBM code is not currently configured to work with default 8-byte reals.
  • More info about the updated scheme and corresponding results can be found in Shpund, J., Khain, A., Lynn, B., Fan, J., Han, B., Ryzhkov, A., Snyder, J., Dudhia, J. and Gill, D., 2019. Simulating a Mesoscale Convective System Using WRF with a New Spectral Bin Microphysics: 1: Hail vs Graupel. Journal of Geophysical Research: Atmospheres. https://doi.org/10.1029/2019JD030576.
    The 43 lookup tables can be downloaded here:
    https://www2.mmm.ucar.edu/wrf/src/wrf_files/

Cumulus

• Updates to Multi-scale Kain-Fritcsh cumulus parameterization scheme:
  *Added Zhang and McFarlane (JGR, 100, 1995) convective momentum transport (CMT) to the MSKF scheme (improves speed of propagation of storms and squall lines and associated changes in horizontal winds components). The option is controlled by cmt_opt_flag inside module_cu_mskf.F, and turned on.
  *The MSKF cumulus parameterization scheme is now working with other PBL schemes, in addition to YSU. But the newly added 3DTKE scheme cannot yet work with MSKF.

• A bug fix for the BMJ cumulus scheme corrects an error with conservation of enthalpy. The fixed code produces less surface rain. More detail can be found in the following paper: https://www.geosci-model-dev.net/8/2915/2015/

• A subgrid-scale cloud-radiation feedback scheme for Betts-Miller-Janjic (BMJ) cumulus is added and activated by namelist option bmj_rad_feedback option in &physics. The scheme is based on precipitation rate. See the following paper for science details: Koh, T.-Y. and R. Fonseca (2016), "Subgrid-scale cloud-radiation feedback for the Betts-Miller-Janjic convection scheme", Quarterly Journal of the Royal Meteorological Society, 142(695), 989-1006. doi: 10.1002/qj.2702. For tropical applications, the authors recommend this scheme to be used with the WDM5, WDM6 or WDM7 cloud microphysics schemes, and with the RRTMG / RRTMG fast radiation scheme. The BMJ scheme should a...

WRF Version 4.1.5

The WRF model has been updated to Version 4.1.5 on March 10, 2020.

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

Physics

Problem:
Newer versions of the GNU compiler more tightly conform to the Fortran standard and do not immediately short circuit IF test processing once a statement is known to be FALSE. This newer and legal behavior recently caused troubles with NoahMP regarding the frequency to process ground water.

When running the NoahMP scheme with the ground water option (opt_run=5), the STEPWTD variable is initialized to a non-zero value. However when opt_run!=5, then the STEPWTD variable remains an uninitialized zero value. In the WRF source code, there are a couple of places where mod(x,STEPWTD) occurs. This causes an immediate "divide by zero" error in the first call to the surface driver.

Solution:
The IF test logic is re-arranged so that only when opt_run=5 (which means that STEPWTD is non-zero) is there, a second IF test (using mod(x,STEPWTD)) to compute whether additional processing takes place.

The purpose of this modification is to allow users access to the latest v4.1.* branch that works with NoahMP. This release fixes that trouble with modified logic, but the still existing problem could extend (depending on the compiler) back to version 3.6.

WRF Version 4.1.4

The WRF model has been updated to Version 4.1.4 on February 12, 2020.

Acknowledgements: We would like to thank Yali Wu (NCAR MMM), Kyo-Sun Lim (Kyungpook National University), Sooya Bae (KIAPS) and Yago Riveiro (Air Quality and Odor Management - AQOM) for their contributions to this release.

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

Compiling

• The replicated symbol "SMOOTHER" in subroutine feedback_domain_nmm_part2 is renamed to be "SMOOTHR" to get HWRF to build and run the regresion test cases
• An ifdef is put around the routine (module_dm.F) that handles pops and pushes of the the communicator stack to make sure the communicators are only required for distributed memory MPI jobs.
• The incorrect use of whereis in configure to locate nc-config is fixed.

Physics

• Changes in the snow/graupel/rain mass and rain number concentration caused by melting of snow/graupel are made to occur at the same time for WDM5, WDM6 and WDM7 microphysics. Also, the cloud water number concentration is added to the CCN number concentration. These changes are more physically reasonable and would leads to decreases in the generation of rain number concentrations and increases in CCN number concentration .
• Fix a problem in Deng shallow scheme when it is combined with other sub-grid cloud schemes (e.g. non-microphysics options that have radiation feedback).
• Fix an occasional divided-by-zero error in SFCLAYREV scheme

Data Assimilation

• Fix a problem in the calculation of effective radius of rain, snow and graupel.

Computing

• The maximum number of eta levels is increased from 1001 to 10001 to avoid REAL porgram failure when the number of vertical levels is more than a thousand.

WRF Version 4.1.3

The WRF model has been updated to Version 4.1.3 on November 25, 2019.

Acknowledgements: We would like to thank Alexander Ukhov (KAUST) , Brian Reen (Army Research Lab), Pedro Jimenez and Greg Thompson of NCAR/RAL, Ted Mansell of NSSL, Alexander Ukhov, KAUST, Gerardo Cisneros-Stoianowski (Mellanox Technologies), Kevin Manning and Jamie Bresch of NCAR/MMM for their contributions to this release.

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

Compiling

• A modification was added to the compile script to print out the correct version number of the WRF model in the compile log.

Physics

• Deng shallow scheme fixed for occasional blow-ups due to uninitialized RADIUSC or a divide by zero.
• Correction to NSSL 2-moment scheme. Snow reflectivities were too low and were reverted to a previous version. Effective radius calculations for droplets/ice (used only by RRTMG) were only calculated at history output times and are now done every time step.
• In 3.5.1, a bug fix was introduced to fix the possibility of dividing by zero in subroutine reftra_sw, in module_ra_rrtmg_sw.F. The fix was to limit the denominator to a small positive number. However, this denominator can be both positive and negative. That V3.5.1 fix was not correct, and introduced cold bias in areas of cloud. This PR fixes the nearly identical problem in all three module_ra_rrtmg_sw*.F files.
• Corrected a problem that caused model to stop when using sf_ocean_physics = 1, with WRF code compiled for bounds checking.
• Using the YSU PBL scheme in combination with either the WSM3 or Kessler MP schemes (no ice) is now fixed to not use ice array.
• When using the MYNN PBL scheme, with icloud_bl = 1 (which is default), restarts did not give bit-for-bit results when compared to a non-restart run. This has been a problem since the option was introduced in V3.8, but is now corrected.
• For Thompson MP, relatively small bug fixes and safety checks have been implemented. Specifically: avoid exceeding max amounts of snow, graupel, or cloud water; adjust snow terminal fall speed; initialize snow moment variables; permit larger max values of ice crystal concentrations.
• Corrected vertical index error in fire module to avoid accessing values of a half-level variable with full-level index.
• Limited max_ts_level to be less than the number of half levels.
• namelist checks are now conducted only on used or allowed domains.

Nudging

• Fixed a problem with observation nudging diagnostic prints. Sometimes the information from multiple observations were mixed together, and sometimes missing observations were printed out.
• Fixed conflict in file units used in obs nudging and Thompson microphysics.

Idealized Cases

• If a user chooses to explicitly list the eta levels for an idealized case, a check has been added to verify that valid eta levels are supplied for idealized cases in the namelist.input file.

Data Assimilation

• A bug fix in the trajectory calculation of specific humidity for CRTM may slightly improve radiance DA results that use water-vapor-sensitive channels. There is not expected to be a large impact.
• Fix WRFDA implementation of alpha_std_dev for tuning flow-dependent B. Current namelist alpha_std_dev cannot be set to values other than 1.0 (default). After the fix, setting alpha_std_dev to a value larger than 1.0 inflates the spread, and setting alpha_std_dev to a value smaller than 1.0 deflates the spread.

Chemistry

• Corrected a typo in diagnostic dust gravitational settling flux.

WRF Version 4.1.2

WRF Model Version 4.1.2

The WRF model has been updated to Version 4.1.2 on July 12, 2019.

Acknowledgements: We would like to thank Changhai Liu (NCAR), Nicolas Baldeck (OpenMeteoData), Emily Collier (FAU Erlangen-Nürnberg), Han Lung (Fujitsu America, Inc.), Jamie Bresch (NCAR) and Anders A. Jensen (NCAR-RAL) for their contributions to this release

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

Compiling

• A modification was added to the compile script to print out the correct version number of the WRF model in the compile log.

Diagnostics

• Bug fix in temperature and winds computation when the “traditional fields” diagnostics option is turned on.
  • For temperature, the moisture is incorrectly removed from the already dry potential temperature perturbation, which leads to a cooler temperature that can be 8-10 K lower in locations near the surface with high moisture content.
  • For winds, when computing the earth-relative winds from the model’s projection-relative winds, both zonal and meridional winds were too large by a factor of two.

Physics

• Logic was added to include the buckets for accumulated radiation fields when the user selects bucket_J > 0. A bug was introduced since WRFV3.9, when the user selected the bucket_J >0, no additional fields were computed or output.
• Bug fix to ensure restart runs are reproducible in nested domains when topographic shading is turned on.
• Bug fixes in Jensen ISHMAEL microphysics
  • Add allocation for single-precision lookup tables which are defined from the double-precision ones. Without this, certain versions of PGI throw an error.
  • Move the calculation of the inherent growth ratio to prevent it from being undefined in certain instances.
  • Store shape parameter, use it to diagnose shape during nucleation and aggregation (transfer between ice categories), and ensure that this value stays in bounds. This prevents the updated shape from going out of bounds in certain instances.
  • Move the mass check for aggregation to occur to around the aggregation subroutine call to prevent the aggregate diagnostics from being undefined.
  • Add a fix to ensure that nucleation won't turn planar particles into columnar ones by limiting this shape to spherical.
  • Set a low limit on nucleation size to 2 microns.

Data Assimilation:

• Fix to allow proper QVAPOR analysis when mp_physics is not set in namelist.input.
• Fix WRFDA V4.1.1 serial compilation failure.
• Fix WRFDA 4DVAR V4.1.1 compilation failure.
• Fix Radar DA memory leak. Some allocated arrays for radar were not deallocated.

WRF Version 4.1.1

WRF Model Version 4.1.1

The WRF model has been updated to Version 4.1.1 on June 4 , 2019.

Acknowledgements: We would like to thank Katie Lundquist (LLNL), Maik Reichert,
RCarpenter and Robert Rozumalski (COMET) for their contributions to this release

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

Compiling

• Following the correct syntax of using CPP #includes, angle brackets are replaced by quotes (frame/module_alloc_space.h)
• The “CHUNK” variable in the Goddard MP and radiation schemes are changed from “CHUNK=16” to “chunk=16” to avoid confusion caused by the arch/configure.default -DCHUNK compiler flag.
• Enforce conditional use of IEEE Fortran 2003 capabilities in v4.1 Goddard schemes, which avoids the failure of WRF compilation using GNU on Linux.

Vertical refinement

• Bug fix for the vertical refinement options. From version 4.0 through 4.1, both vertical refinement options were broken due to the introduction of hybrid vertical coordinate option. For online vertical refinement (within the WRF model using namelist vertical_refine_method) with only a single input domain, the incorrect WRF code had uninitialized arrays that defined the vertical coordinate in the child domain. However, any users with vertical refinement activated AND with input_from_file = t,t were never impacted. For offline vertical refinement (using ndown with vert_refine_fact), the initial conditions also only had the lower portion of the 1d arrays initialized (and those were initialized incorrectly). Modifications were introduced to fix both refinement options, and the modifications now support the hybrid and the terrain-following vertical coordinate.

Dynamics

• Bug fix for the option diff_6th_opt. A logical variable is not specified before it is used, which can lead to model failure when running with this option on some machines and using some compilers.

Physics

• Force positive definite with small mass and number from RRTMK for cloud, snow and graupel in the computation of effective radius to avoid floating exception

Miscellaneous

• Fix misleading error message when an auxiliary file was missing
• Correct the typo in the Ishmael DFI package
• Correct some instructions in README.namelist
• Add missing commas to LANDUSE.TBL
• Fix compiler-sensitive looping for random seeds initialization in stochastic processing
• Add controlled stop when timing problems with the boundary data are detected

Data Assimilation

• Bug fix for missing values in bufr files. This fix prevent the errors from occurring in the debug build
• Bug fix for dependencies in DA dm_bcast_interfaces. All known missing use statements related to wrf_dm_bcast_* calls are corrected.
• Avoid DA EnVAR unnecessary ep allocation to reduce memory requirement
• Fix DA dual-res hybrid significantly different results with different number of processors.