Model Solver
- fully compressible nonhydrostatic
equations with hydrostatic option
- complete coriolis and curvature terms
- two-way nesting with multiple nests and nest levels
- one-way nesting
- experimental moving nest
- mass-based terrain following coordinate (note that the height-based
dynamic core is no longer supported)
- vertical grid-spacing can vary with height
- map-scale factors for conformal projections:
* polar stereographic
* Lambert-conformal
* Mercator
- Arakawa C-grid staggering
- Runge-Kutta 2nd and 3rd order timestep options
- scalar-conserving flux form for prognostic variables
- 2nd to 6th order advection options (horizontal and vertical)
- time-split small step for acoustic and gravity-wave modes:
* small step horizontally explicit, vertically
implicit
* divergence damping option and vertical time off-centering
* external-mode filtering option
- lateral boundary conditions
* idealized cases: periodic, symmetric, and
open radiative
* real cases: specified with relaxation zone
- upper boundary absorbing layer option
- positive definite advection scheme for scalars
(microphysics species, and tke) (new in V2.2)
- SST and greenness fraction update during long
simulations
- Two-way and one-way nesting
Physics
- microphysics
* Kessler
* WRF Single Moment (WSM) 3, 5 and 6 class
* Lin et al.
* Eta Ferrier
* Thompson (a new version in V2.2)
- cumulus parameterization
* Kain-Fritsch with shallow convection
* Betts-Miller-Janjic
* Grell-Devenyi ensemble
- planetary boundary layer
* Yonsei University (S. Korea)
* Mellor-Yamada-Janjic
* MRF
- surface layer
* similarity theory MM5
* Eta or MYJ
- land-surface
* slab soil model (5-layer thermal
diffusion)
* Noah
land-surface model
* Urban
canopy model (works with Noah LSM, new in V2.2)
* RUC LSM
- longwave radiation
* RRTM
* CAM
- shortwave radiation
* simple MM5 scheme
* Goddard
* CAM
- sub-grid turbulence
* constant K diffusion
* 2-D Smagorinsky
* predicted TKE
- land-use categories determine
surface properties
- analysis nudging (3 D only) (new
in V2.2)
- observation nudging (new in V2.2)
Inputs for WRF initialization
- idealized: several cases set up, both 2D
and 3D
- real-data using Standard Initialization (SI) conversion from
Grib files
I/O Option
- netCDF, most common. Work with all supported
graphics.
- PHDF5 (Kent Yang, University of Illinois)
- GriB 1 (Todd Hutchinson, WSI)
- GriB 2(Todd Hutchinson, WSI) (new in V2.2)
- Binary
- parallel netCDF (Argnnon National Lab, experimental only)
Platforms it runs on
- Compaq: personal workstation, ES40, MPP (Pittsburgh
TCS)
- IBM: Power5/Power4 (e.g. NCAR blackvista/bluesky systems)
- SGI: Origin 2000, Altix
- Linux: PGI and Intel compilers (ifort 8.1 recommended)
Pentium 3/4 clusters and SMPs
Pentium 4 cluster iJet system at NOAA FSL
Intel Xeon IA32
IA64/Linux MPP (SGI Altix)
IA64/Linux MPP (HP Superdome at PNNL)
IA64/Linux MPP (NCSA)
IA64/Linux SMP (local)
AMD Opteron
- Alpha Linux (cluster)
- Sun (single and SMP)
- Cray: Unicos/X1, X1e (vector), and XD1 (Opteron) series
- HP-UX (experimental)
- Apple: G5 (no DM-parallel yet)
Porting in progress:
- NEC: SX/6
- Fujitsu: VPP 5000
Software Architecture
- Hierarchical software architecture that insulates
scientific code (Model Layer) from computer architecture (Driver
Layer).
- Multi-level parallelism supporting shared-memory (OpenMP), distributed-memory
(MPI), and hybrid share/distributed modes of execution.
- Active data registry: defines and manages model state fields,
I/O, nesting, configuration, and numerous other aspects of WRF
through a single file, called the Registry.
- ESMF Time Management, including exact arithmetic for fractional
time steps (no drift); model start, stop, run length and I/O frequencies
are now specified as times and time intervals in 2.0 (rather than
numbers of steps, as in 1.3 and earlier).
- Documentation,
both on-line (web based browsing tools) and in-line.
- Two-way nesting:
* Easy to extend: forcing and feedback of
new fields specified by editing a single table in the Registry
* Efficient: 5-8% overhead on 64 processes of IBM
- Moving nest:
* support specified and automatic moving nest
using a vortex-following algorithm
* fully parallel
* telescoping
* efficient, less than 2% overhead for movement
- Enhanced I/O options:
* NetCDF, Parallel HDF5 formats, and Grib1
* split-output file option available for netCDF
* units in netCDF files are conforming to standard
* Five auxiliary history output streams separately controllable
through the namelist
* Output file names and time-stamps specifiable through namelist
* Special output stream for 3DVAR
- Efficient execution on a range of computing
platforms:
* IBM SP systems, (e.g. NCAR "bluesky" Power4-based
system)
* HP/Compaq Alpha/OSF workstation, SMP, and MPP systems (e.g.
Pittsburgh Supercomputing Center TCS)
* SGI Origin and Altix
* Linux/Intel
. IA64 MPP (HP Superdome, SGI Altix, NCSA
Teragrid systems) . IA64 SMP
. AMD Opteron
. Pentium 3/4 SMP and SMP clusters (NOAA/FSL iJet system)
. PGI and Intel compilers supported
* Alpha Linux
* Sun Solaris (single threaded and SMP)
* Cray X1, X1e (vector), and XD1 (Opteron) series
* Other ports under development:
NEC SX/6
Fujitsu VPP 5000
Features new in 2.1 version of WRF software:
- Automatic moving nest.
- RSL_LITE: optional new communication layer,
scalable to very large domains, nest support.
- Memory usage improvement.
- Generalized physics interface.
- ESMF integration: WRF can be run as an ESMF
component.
- WRF-Var and model synchronization.
