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WRF Model Version 3.4: UPDATES

WRF Model Update

The WRF model tar file has been updated to Version 3.4 on April 6, 2012. For known problems in V3.4, please click here.

The WRF Pre-Processing System (WPS) has been updated to Version 3.4.

Note: V3.4 WRF can use wrfinput and wrfbdy files from earlier V3 versions only if one sets hypsometric_opt = 1 in namelist &domains. However if you would like to use newer options introduced in 3.4 (see below), you may benefit from the change if wrfinput and wrfbdy files are regenerated.

As always, be cautious when using new options.

If you are interested in seeing how V3.4 has been tested, click here.

New in Version 3.4:


- Land surface models:

* Noah-MP (Niu et al., 2011) (MP: multi-physics): It uses multiple options for key land-atmosphere interaction processes. Noah-MP contains a separate vegetation canopy defined by a canopy top and bottom with leaf physical and radiometric properties used in a two-stream canopy radiation transfer scheme that includes shading effects. Noah-MP contains a multi-layer snow pack with liquid water storage and melt/refreeze capability and a snow-interception model describing loading/unloading, melt/refreeze, and sublimation of the canopy-intercepted snow. Multiple options are available for surface water infiltration and runoff, and groundwater transfer and storage including water table depth to an unconfined aquifer. Horizontal and vertical vegetation density can be prescribed or predicted using prognostic photosynthesis and dynamic vegetation models that allocate carbon to vegetation (leaf, stem, wood and root) and soil carbon pools (fast and slow). Thanks to Zong-Liang Yang (UT-Austin) and Guo-Yue Niu (Biosphere 2, Univ. of Arizona) for the development, and Joakim Refslund Nielsen (Risø DTU), Kevin Manning (NCAR-MMM) , Michael Barlage and Mukul Tewari (NCAR-RAL) for implementing it in WRF. For more information, please click here.
* SSiB: This is the third generation of the Simplified Simple Biosphere Model (Xue et al. 1991; Sun and Xue, 2001). SSiB is developed for land/atmosphere interaction studies in the climate model. The aerodynamic resistance values in SSiB are determined in terms of vegetation properties, ground conditions and the bulk Richardson number according to the modified Monin-Obukhov similarity theory. SSiB-3 includes three snow layers to realistically simulate snow processes, including destructive metamorphism, densification process due to snow load, and snow melting, which substantially enhances the model's ability for the cold season study. To use this option, ra_lw_physics and ra_sw_physics should be set to either 1, 3, or 4. The second full model level should be set to no larger than 0.982 so that the height of that level is higher than vegetation height. Thanks to Xue and de Sales of UCLA.

- Microphysics option:

* NSSL 2-moment (Mansell, Ziegler and Bruning, JAS, 2010): The scheme is a 2-moment one developed at the National Severe Storms Laboratory. It predicts the mass mixing ratio and number concentration for six hydrometeor species: cloud droplets, rain drops, ice crystals, snow, graupel, and hail. A unique feature is the additional prediction of average graupel particle density, which allows graupel to span the range from frozen drops to low-density graupel. Hail is produced only by wet growth of graupel to try to repensent true hail rather than merely high-density ice. An option allows prediction of cloud condensation nuclei (CCN) concentration (intended for idealized simulations). The scheme also features adaptive sedimentation to allow some size sorting but prevent spurious large particles (and radar reflectivity values) that can arise from two-moment microphysics, particularly for the larger precipitation categories (graupel, hail, and rain). Size distribution shape parameters and a number of other options can be set in the code. The scheme is intended for cloud-resolving simulations (dx <= 2km) in research applications. Thanks to T. Mansell of NSSL.

- Cumulus option:

* New SAS for HWRF (option 84): not yet tested for ARW (Thanks to NCEP)

- Atmospheric radiation option:

* Fu-Liou-Gu: multiple bands, cloud and cloud fraction effects, ozone profile from climatology, shortwave can allow for aerosols. For more details and references, click here. Thanks to Gu of UCLA.

- PBL option:

* QNSE-EDMF: Daytime part of QNSE PBL modified to use mass flux method with shallow convection activated by namelist option mfshconv=1 (default). Thanks to J. Pergaud of Numtech, France. Setting mfshconv = 0 gives QNSE result.

- Surface layer physics option:

* A revised MM5 surface layer scheme (sf_sfclay_physics = 11): remove limits and use updated stability functions. (Jimenez et al., MWR 2012). Thanks to P. Jimenez of CIEMAT, Spain.

- Others:

* topo_wind: Topographic correction for surface winds to represent extra drag from sub-grid topography and enhanced flow at hill tops. (Jimenez and Dudhia, JAMC 2012). The option requires extra input from geogrid. Thanks to P. Jimenez of CIEMAT, Spain.

* sea ice albedo: option to have albedo over sea ice to depend on air, skin and snow. This is controlled by the namelist option seaice_albedo_opt. Thanks to C. Mills of Univ. of Illinois.

* A new urban table is introduced for sf_urban_physics = 1 option, and it is named URBPARM_UZE.TBL. If one wants to use it, rename it to URBPARM.TBL. Thanks to Thomas Loridan and Sue Grimmond of King's College, UK.


- WENO (Weighted Essentially Non-Oscillatory) advection scheme: The scheme may help with inconsistencies in the microphysical moments at cloud edges. Both 5th order and 5th order with positive-definite limiter are available. Thanks to T. Mansell of NSSL.

Improvements and Bug fixes:


Atmospheric Radiation:

- Goddard shortwave scheme (ra_sw_physics = 1): diagnositic field RSWTOA corrected.


- Thompson: bug fix and updates.
- Morrison: minor change to the limits on autoconversion source of rain number when cloud water is depleted. Major bug fix for V3.3.1 version for ice fallspeed (posted 11/16/11).
- WDM5/6: fix for nccn variable on lateral boundary.
- Eta scheme: updated to High-Res Window version operational at NCEP.


- Tiedtke: A new trigger is added (controlled by cutrigger in the code; the old one is stil the default). It is based on a diluted air parcel testing, while the old trigger is based on the moisture convergence. New organized entrainment and turbulent entrainment/detrainment rate for deep convection based on ECMWF method is added. Thanks to C. Zhang of Univ of Hawaii.
- G3 + shallow: minor fix for shallow part.

Planetary boundary layer physics:

- YSU: improved Pr number computation and change to lower limits on diffusion
- MYJ and MYJSFC: updated to operational version
- MYNN and MYNNSFC: updated (see code for details). Thanks for J. Olson of NOAA.
- ACM2: bug fix to treat convective adjustment at the first time step for occasional problems for small grid sizes.
- TEMP: bug fix for occasional blowups.

Surface physics:

- RUC LSM: use MODIS; capability to specify soil and land-use parameters based on a mosaic approach. Two new namelist parameters are introduced: mosaic_lu and mosaic_soil, the default values are 0, but to switch to mosaic specifications these namelist parameters should be set to 1 (not necessary for both of them, could be default for soil and mosaic for land-use, or visa versa). Tuning some parameters in snow model to get more realistic snow melting rates.
- PX LSM: MODIS support, lake ice treatment, snow albedo tretaments, bug fixes for soil moisture nudging and others.
- tmn_update option: minor fix.
- isftcflx option updated to increase drag at lower wind speed.
- sst_skin option: bug fix for using sst_skin without sst_update option

Gravity Wave Drag: clean-up, minor fix, add diagnostic output


- Spectral-nudging: fix for dtramp coefficient.
- Gridded nudging: fix for loop indices for smooth function in surface nudging

Single-Column Model (SCM):

- Updated

Stochastic kinetic-energy backscatter scheme:

- Default namelist values for tot_backscat_t and tot_backscat_psi have been changed.
- bug fix for restart.
- SKEB arrays in boundary file have been removed.


- Default values for these namelists have been changed:

* hypsometric_opt = 2 (affecting both real, wrf model and ndown) - this will prevent using previously generated wrfinput/wrfbdy files used in V3.4. However one can explicitly set this option to 1.
* interp_theta = .false. (real only)
* lagrange_order = 2 (real only)

For details on hypsometric_opt and interp_theta, see paper by Wee et al. (2012)

- Masked SST handled better in real.
- Surface pressure recalculated in ndown.
- a fix for idealized tropical cyclone initialization.
- a fix for polar projection for grib IO.
- fixes for binary IO.


- The restriction to compile without nesting is removed.


- A few physics sensitivity-related namelist variables are removed: icloud, isfflx, ifsnow.


New Features:
- A capability to interpolate a physics variable read-in or computed on the coarse grid to nest.
- Added support for SGI MPT, and NEC SX

- pnetCDF on small-memory machine.


- Because of a problem with bit-for-bit results with Version 3.3.1 and PGI, the arch/configure_new.defaults file has been edited to comment out '-fastsse,' correcting the problem.


Previous Update

WRF V3.0.1
WRF V3.0.1.1


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