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WRF Model Version 3.8: UPDATES

WRF Model Update

The WRF model tar file has been updated to Version 3.8 on April 8, 2016. For known problems in V3.8, please click here.

The WRF Pre-Processing System (WPS) has been updated to Version 3.8.

Note: V3.8 WRF can use wrfinput and wrfbdy files from V3.6 and 3.7 versions. Please note that the VEGPARM.TBL and URBPARM.TBL in run/ are updated in V3.8, and must be used with 3.8 code.

As always, be cautious when using new options.

If you are interested in seeing how V3.8 has been tested, click here.

New in Version 3.8:


* Kain-Fritsch cumulus potential scheme (cu_physics=10): This scheme modifies the Kain-Fritsch ad-hoc trigger function with one linked to boundary layer turbulence via probability density function using the cumulus potential scheme of Berg and Stull (2005) (Berg et al. 2013 MWR). (Thanks to Jerome Fast and Balwinder Singh of PNNL) (details)

* A new option for climatological aerosol and RRTMG radiation interaction (aer_opt = 3): This option makes use of climatological water- and ice-friendly aerosol already used by Thompson (mp_physics=28) option as input to RRTMG. It currently only works with mp_physics = 28. (Thanks to Greg Thompson and Trude Eidhammer of NCAR/RAL)


* Added a new flux-adjusting surface data nudging scheme (Alapaty et al. (2008, JAMC). Note that a special version of OBSGRID is required for this option. Read more. (Thanks to Kiran Alapaty and Jian He of EPA)

* Added a new 30 arc second topography data that replaces the old 30 sec TOPO.

Improvements and Bug fixes:



- Thompson: (Thanks to Greg Thompson of NCAR/RAL)

(a) Fix non-aerosol-aware value of cloud droplet number concentration units of per kg, not per cubic meter.
(b) Updated snow terminal velocity while melting making it slower because it too rapidly fell at typical rain velocities.
(c) Remedy a mis-match for recently coupled cloud physics water/ice sizes computed explicitly in microphysics with lower minimum values similar to default a priori table values.

- WSM, WDM schemes: bug fix in melting term with a density factor. WDM6 also was fixed for a bug that will increase graupel and decreases rain a bit above melting layer (Thanks to Sooya Bae of KIAPS, S. Korea)

- NSSL 2-moment scheme: Updated (Thanks to Ted Mansell of NSSL)

(a) Fixed issue with reflectivity conservation for graupel melting into rain. Rain number concentrations were too low, resulting in excessive reflectivity of a couple dBZ.
(b) Turned off diagnostic meltwater on graupel for reflectivity (more realistic results).
(c) Changed vapor ice nucleation back to Meyers-Ferrier method (original scheme).
(d) Reduced snow aggregration efficiency and restricted aggregation to higher temperatures (assuming dendrites and mechanical aggregation).
(e) Helped performance in sedimentation with flag "do_accurate_sedimentation" to control recalculation of fall speeds when more than one sub-time step is needed (often happens with large time steps and small dz near the ground):.
(f) Increased maximum mean droplet radius from 40 to 60 microns, which alleviates spurious number concentration increases at low CCN concentration.
(g) Updates for compatibility with WRF-NMM.
(h) Fixed snow fall speeds.
(i) Fixed a duplicate factor from hail reflectivity that was causing a loss of about 6 dBZ.

- SBM: Fixed CCN and landmask issues in initializing them. (Thanks to Barry Lynn of The Institute of the Earth Science, The Hebrew University of Jerusalem, Isaral)


- New Tiedtke (cu_physics=16): (Thanks to Chunxi Zhang of U. of Hawaii)

(a) Improved water budget by considering the effect of precipitation difference in downdraft in tendencies.
(b) Allowing cloud water to change to rain water at all cloud levels when cloud water is greater than a threshold.
(c) Increasing entrainment rate for deep convection.
(d) Reducing entrainment in downdraft from 3.e-4 to 2.e-4.
(e) Allowing for entrainment only when buoyancy is positive.

- Kain-Fritsch schemes (cu_physics = 1, 11, 99): can output updraft and downdraft detrainment/entrainment rates. It is activated by namelist option kf_edrates = 1.(Thanks to Jeremiah Johnson, Envrioncorp)

Planetary boundary layer and surface layer physics:

- YSU and Shin-Hong PBLs: background diffusion was reduced, which helps removing a large cold bias at the model top layer. (Thanks to Songyou Hong of KIAPS, Korea)

- ACM2 PBL: RMOL updated after initial calculation in the PX-SFCLAY.(Thanks to Roberb Gilliam and Jon Pleim of EPA)

- MYNN PBL: (Thanks to Joe Olson, Jaymes Kenyon and Wayne Angevine of NOAA)

(a) Added subgrid scale cloud output for coupling to radiation
schemes (default on: icloud_bl =1 in phys namelist).
(b) Added WRF_DEBUG prints (at level 3000)
(c) Added Tripoli and Cotton (1981) correction.
(d) Added namelist option bl_mynn_cloudmix to test effect of mixing cloud species (default on).
(e) Added mass-flux option (bl_mynn_edmf, = 1 for StEM, 2 for TEMF).
This option is off by default (=0).
Related (hidden) options:
bl_mynn_edmf_mom = 1 : activate momentum transport in MF scheme
bl_mynn_edmf_tke = 1 : activate TKE transport in MF scheme
bl_mynn_edmf_part= 1 : activate areal partitioning of ED & MF
(f) Added mixing length option (bl_mynn_mixlength)
(g) Added more sophisticated saturation checks, following Thompson scheme
(h) Added new cloud PDF option (bl_mynn_cloudpdf = 2) from Chaboureau and Bechtold (2002, JAS, with mods)
(i) Added capability to mix chemical species when env variable
WRF_CHEM = 1, thanks to Wayne Angevine.
(j) Added scale-aware mixing length, following Junshi Ito (Ito et al. 2015, BLM).

Land Surface physics:

- NoahMP: (Thanks to Mike Barlage of RAL/NCAR)

(a) fixed a bug in the OPT_STC=3, where it was effectively reproducing OPT_STC=1 results.
(b) added a glacier option (OPT_GLA) based on the simple Noah glacier code.
(c) added soil/snow surface resistance options (OPT_RSF)
(d) added vegetation fraction and LAI options (OPT_DVEG) to cover different combination of reading input, reading tables and calculating vegetation
(e) fixed accumulated snow (Thanks to Robert Rozumalski of UCAR/COMET)

- Noah:

(a) added option (opt_thcnd) for calculation of soil thermal conductivity for soil type 3 (sandy loam) and 4 (silt loam) based on results in Massey, et al (2014; JAMC) (Thanks to Jason Knievel of NCAR/RAL and Jeff Massey of Climate Corporation)
(b) fixes high-frequency oscillations in LH flux seen in time series output over snow.
(c) Fixed Noah glacial and sea-ice to allow negative moisture flux

- Urban physics:

(a) added generic specification of urban land classes to tables
(b) reorganized urban tables (must use new URBPARM*TBL)
(c) a,b fix the bug when NLCD40 category data is used with urban physics options (Thanks for the report by Jeff Massey of Climate Corporation)
(d) urban physics must be used for all domains
(e) fixed a memory bug associated with urban physics options BEM and BEP (Thanks for a report by Yizhou Zhang of IUM, China)

- RUC LSM: modification of snow fraction computation for the urban category with updated VEGPARM.TBL. Minor bug fixes in diagnostics. (Thanks to ESRL/NOAA)

- PX LSM: Surface water vapor mixing ratio calculation added for land surface, which is passed to PX-SFCLAY for use over all non-water and non-frozen surfaces. Also PAR function and impact on transpiration modified according to Echer et al.(2015). (Thanks to Robert Gilliam and Jon Pleim of EPA)

- SSiB: Correct a bug that causes aerodynamic conductance less or equal to zero in some cases. (Thanks to Fernando de Sales of UCLA)


- Simple mixed-layer ocean: added relaxation time for mixed-layer ocean model.

- 3D ocean: Added missing latent heat flux in heat budget; corrected the sign of salinity contribution to moisture flux. (Thanks to Camila Gomes of Florida Tech)


- FLG: Fixed a problem with diagnostic radiation tendency output. (Thanks to Gu of UCLA)

WRF-Hydro 4.0: (more info)

The WRF-Hydro 4.0 will be released in May 2016, following WRF 3.8 release. This version has many enhanced features and new physical options compared to the previous release. The updated NoahMP offline package provides consistent NoahMP land surface model physics with WRF 3.8 version. WRF-Hydro 4.0 also adds two new channel routing options: NCAR Reach based channel routing and the RAPID model, driven by WRF-Hydro interface. The optimization of memory usage allows WRF_hydro 4.0 users to be able to run very high resolutions over large domains. The split of different terrain routing time step and channel routing step allows user to use larger time steps for terrain routing compared to channel routing time steps and ultimately improves the computing time. More details will be addressed in the official WRF-Hydro 4.0 release documents.


- icloud = 3: fixed a significant bug that caused excessive cloud estimate. (Thanks to Greg Thompson of NCAR/RAL)

- Add a new namelist, use_mp_re, to control the interaction between effective radii computed in some microphysics with RRTMG radiation.

- Hail diagnostics: Increased the threshold for the number concentration for hail/graupel. (Thanks to Greg Thompson of NCAR/RAL)

- Topo shading: Remove some shadowmask initialization to -1, and
avoid night-time shadowmask values in MPI runs.

- CAM physics (PBL, Cu, Shcu): Make conversion factors between specific humidity and mixing ratio exact. This affects moisture and cloud tendencies.

- Observation nudging: fixed a runtime error when nesting with more than 3 domains and Thompson scheme are used. (Thanks to Brian Reen of ARL)

- Analysis nudging: fixed an error that resulted in the incorrect analysis being nudged towards the ramp-down period. Added checks to ensure the options selected are actually supported. (Thanks to Brian Reen of ARL)

Moving nests:

- The limitation to use less than 55 vertical levels has been removed. (Thanks to Sam Trahan and John Michalakes of NCEP)


- All idealized initialization modules: the perturbation height calculation are modified to use *dnw, rather than *1./rdnw, making it the same as in start_em. This does change the round-off of the calculation, hence the model results (Thanks Katie Lundquist of LLNL)

- vertical refinement in nest: updated and improved (Thanks Katie Lundquist of LLNL)

- Specified boundary conditions: reset spec_bdy_final_mu = 1, which no longer causes restart issue with nest application.

- ndown: added scalar coupling in lateral boundary file.

- new namelist default: the default values for the following namelists have been changed:

num_land_cat = 21 (from 24)
lagday = 150 (from 0)


- Option use_theta_m = 1 works with nests. Implementation is improved to reduce round-off inaccuracy.

- Fixed an extrapolation error for top_lid option.

- Fixed an error with LES sfs_opt = 1 and 2. (Thanks to Jeff Mirocha of LLNL)


- Nested run performance was improved by not doing allocating / deallocating intermediate domains. (Thanks to SGI and Fujitsu)
- sint: optimized, but little impact on performance except on Fujitsu (Thanks to Fujitsu)
- New compile option for Mac OSX using CLANG (Thanks to Dominikus Heinzeller of Karlsruhe Institute of Technology, Germany)
- Bug fixes.


Previous Update

WRF V3.0.1
WRF V3.0.1.1


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