Welcome to WRF User’s Guide!

Note

Please see the Foreword for information on WRF Users’ Guide contributors and acknowledgments.

Full List of Content Included in this Guide

• WRF Overview
  • WRF Modeling System Components
    • WRF Preprocessing System (WPS)
    • Initialization
    • WRF-ARW Solver
    • WRF Data Assimilation (WRFDA)
    • Post-processing, Analysis, and Visualization Tools
  • Resources
• Compiling
  • Required Compilers and Scripting Languages
  • Required and Optional Libraries
    • NetCDF
    • MPI
    • GRIB2 Libraries
    • GRIB1 Output Format
  • Building the WRF Code
    • Configure WRF
    • Compile WRF
    • Failed WRF Compile
    • WRF Directory Structure
  • Building WRFDA, WRF-Chem, and WRF-hydro
  • Building the WRF Preprocessing System (WPS)
    • Configure WPS
    • Compile WPS
    • Failed WPS Compile
  • Using the “clean -a” Tool
• The WRF Preprocessing System (WPS)
  • Function of Each WPS Program
    • Program Geogrid
    • Program Ungrib
    • Program Metgrid
  • Running the WPS
    • Step1: Define model domains with geogrid
    • Step 2: Extracting Meteorological Fields from GRIB Files with Ungrib
    • Step 3: Horizontally interpolating meteorological data with metgrid
  • WPS Nested Domains
  • USGS and MODIS Land Use
  • Gravity Wave Drag Scheme Static Data
  • Using Multiple Meteorological Data Sources
    • Interpolating Time-invariant Fields
    • Interpolating from Multiple Sources of Meteorological Data
  • Using Non-isobaric Meteorological Data Sets
  • Alternative Initialization of Lake SSTs
  • Parallelism in the WPS
  • Checking WPS Output
  • WPS Utility Programs
    • avg_tsfc.exe
    • mod_levs.exe
    • calc_ecmwf_p.exe
    • height_ukmo.exe
    • plotgrids.ncl
    • g1print.exe
    • g2print.exe
    • rd_intermediate.exe
  • Writing Meteorological Data to the Intermediate Format
  • Required Input for Running WRF
  • Using MPAS Output for WRF Input
  • Creating and Editing Vtables
  • Writing Static Data to the Geogrid Binary Format
  • NLCD Urban Fraction Field
  • WPS Namelist Variables
    • &share Section
    • &geogrid Section
    • &ungrib Section
    • &metgrid Section
  • GEOGRID.TBL Options
  • Index Options
  • METGRID.TBL Options
  • Geogrid/Metgrid Interpolation Options
    • four_pt: Four-point Bi-linear Interpolation
    • sixteen_pt: Sixteen-point Overlapping Parabolic Interpolation
    • average_4pt: Simple Four-point Average Interpolation
    • wt_average_4pt: Weighted Four-point Average Interpolation
    • average_16pt: Simple Sixteen-point Average Interpolation
    • wt_average_16pt: Weighten Sixteen-point Average Interpolation
    • nearest_neighbor: Nearest Neighbor Interpolation
    • search: Breadth-first Search Interpolation
    • average_gcell: Model Grid-cell Average
  • Land Use and Soil Categories in the Static Data
  • WPS Output Fields
    • Geogrid Output
    • Metgrid Output
• WRF Initialization
  • Building Initialization Programs
  • Initialization for Idealized Cases
  • Initialization for Real Data Cases
    • Real-data Test Case
  • Backward-compatibility
  • Setting Model Vertical Levels
• Running WRF
  • Running Idealized Cases
  • Running Real-data Cases
  • Restart Capability
  • WRF Nesting
    • Basic Nesting
    • One-way Nesting Using Ndown
    • Automatic Moving Nest (Vortex-following)
    • Specified Moving Nest
  • Run-time Capabilities
    • SST Update
    • Adaptive Time-stepping
    • Stochastic Parameterization Schemes
    • Analysis Nudging (Upper-air and/or Surface)
    • Observational Nudging
    • Digital Filter Initialization
    • Bucket Options
    • Global Simulations
    • I/O Quilting
• WRF Dynamics
  • Hybrid Vertical Coordinate
  • Diffusion Options (diff_opt)
    • K Options (km_opt)
    • 6th Order Horizontal Diffusion (diff_6th_opt)
    • Nonlinear Backscatter Anisotropic (NBA) (sfs_opt)
  • Damping
    • Upper Damping (damp_opt)
    • Vertical Velocity Damping (w_damping)
    • Divergence Damping (smdiv)
    • External Mode Damping (emdiv)
    • Time Off-centering (epssm)
  • Advection
    • Horizontal Advection Order
    • Vertical Advection Order
    • Monotonic Transport and Positive-definite Advection
    • Weighted Essentially Non-oscillatory Options (WENO)
    • Implicit Explicit Vertical Advection (IEVA)
  • Other Dynamics Options
  • Lateral Boundary Conditions for Idealized Cases
  • Lateral Boundary Conditions for Real-data Cases
• WRF Physics
  • Cumulus Parameterization
    • Cumulus Options
    • Cumulus Details and References
    • Shallow Convection
  • Microphysics
    • Microphysics Options
    • Microphysics Option Details and References
  • Radiation
    • Longwave Radiation Schemes
    • Longwave Radiation Scheme Details and References
    • Shortwave Radiation Schemes
    • Shortwave Radiation Scheme Details and References
    • Input to Radiation Options
    • Clouds and Cloud Fraction Options
    • Radiation Time Step (radt)
  • Planetary Boundary Layer Physics
    • PBL Scheme Options
    • PBL Scheme Details and References
    • Additional PBL Options
    • PBL and Land Surface Time-step (bldt)
    • Model Grid Spacing
    • Turbulence and Diffusion
  • Surface physics
    • Surface Layer Schemes
    • Surface Layer Scheme Details and References
    • Land Surface Model
    • LSM Scheme Details and References
    • PBL and Land Surface Time-step (bldt)
    • Model Grid Spacing
    • Turbulence and Diffusion
    • Tropical Cyclone Options
    • Fractional Sea Ice
    • Sub-grid Mosaic
    • Sea-surface Update
    • Regional Climate Options
    • Accumulation Budgets
    • Lake Model
    • WRF-Hydro
  • Using Physics Suites
    • NSF NCAR Convection-permitting Suite
    • NSF NCAR Tropical Suite
    • Overriding Physics Suite Options
  • Other Specific Applications
    • Tropical Storms and Cyclones
    • Long Simulations
    • Windfarm
    • Surface Irrigation Parameterization
    • WRF-Solar
    • MAD-WRF
    • Physics Sensitivity Options
• Namelist Variables
  • &time_control
  • &domains
  • &physics
  • &stoch
  • &dynamics
  • &bdy_control
  • &fdda
  • &noah_mp
  • &dfi_control
  • &grib2
  • &scm
  • &tc
  • &diags
  • &afwa
  • &ideal
• WRF Output
  • WRF Output Fields
  • Special WRF Output Variables
  • Run-Time I/O Option
  • Output Diagnostics
    • Time Series Output
    • Pressure Level Output
    • Convective Storm Diagnostics
    • Climate Diagnostics
    • Time-averaged Output
    • Weather Diagnostics
    • Solar Forecasting Diagnostics
    • Accumulated Physics Tendencies Output
    • Miscellaneous Output Options
  • Using Multiple Lateral Boundary Condition Files
  • Checking Output
• Troubleshooting
  • Model Stops - No Error or Segmentation Fault
    • Inadequate Memory
    • Problem with Input Data
    • Segmentation Fault
    • Complex Topography at High Model Resolutions
    • Debugging
  • Namelist Issues
    • “ERRORS while reading namelists…”
    • “SIZE MISMATCH”
  • Best Practices
  • Frequently Asked Questions (FAQ)
• WRF Software & Computation
  • WRF Build Mechanism
    • How the WRF Build Works
  • Registry
    • Registry Syntax
    • Registry Entries
  • WRF Architecture
  • I/O Applications Program Interface (I/O API)
  • Timekeeping
  • Computation
  • Quilting
  • Software Documentation
  • Performance
• WRF Post-processing
  • NCAR Command Language (NCL)
    • WRF and NCL
    • What is NCL?
    • Required Software
    • Environment Variable
    • .hluresfile
    • Create NCL Scripts
    • Run NCL Scripts
    • WRFUserARW.ncl Functions
    • NCL Built-in Functions
    • Adding Diagnostics Using Fortran Code
  • wrf-python
  • Read/Interpolate/Plot (RIP)
    • Required Software
    • Environment Variables
    • Compiling RIP and Associated Programs
    • Preparing data with RIPDP
    • Running RIPDP
    • The RIP User Input File
    • Plot Specification Table
    • Running RIP
  • ARWpost
    • Required Software
    • Environment Variables
    • Configure and Compile ARWpost
    • Edit the namelist.ARWpost file
    • Run ARWpost
    • Viewing Output
    • Troubleshooting
  • NCEP Unified Post-Processor (UPP)
    • UPP Software Requirements
    • Obtaining the UPP Code
    • UPP Functionalities
  • VAPOR
    • Basic Capabilities of VAPOR with WRF-ARW Output
    • VAPOR Requirements
    • VAPOR Support Resources
    • Basic Steps for Using VAPOR to Visualize WRF-ARW Data
• WRF Utilities and Tools
  • read_wrf_nc
    • Install read_wrf_nc
    • Run read_wrf_nc
  • iowrf
    • Install iowrf
    • Run iowrf
  • p_interp
    • Install p_interp
    • Edit the Namelist
    • Run p_interp
  • TC Bogus Scheme
    • Namelist Options
    • Program tc.exe
    • Running tc.exe
  • proc_oml.f
    • Install proc_oml.f
    • Run proc_oml.f
  • Converting Graphics
    • ImageMagick
    • Converting ncgm (NCAR Graphics) File Format
  • Basic Unix Commands
  • Design WRF Model Domains
  • Display ungrib (Intermediate) Files
  • NetCDF Data
    • NetCDF Documentation
    • NetCDF Utilities
  • GRIB Data
    • Documentation and Decoders
    • GRIB codes
    • Display GRIB Header and Field Information
    • Convert GRIB Data to NetCDF Format
    • Displaying GRIB Files
  • Model Verification
  • OBSGRID
    • OBSGRID Program Flow
    • Source of Observations
    • Objective Analysis Techniques in OBSGRID
    • Quality Control for Observations
    • Additional Observations
    • Surface FDDA Option
    • Objective Analysis on Model Nests
    • How to Run OBSGRID
    • Output Files
    • Plot Utility Programs
    • Format of Observations
    • OBSGRID Namelist
• WRF Data Assimilation (WRFDA)
  • Installing WRFDA
    • Obtaining WRFDA Source Code
    • Build WRFDA Libraries
    • Compile WRFDA for 3D-Var and 4D-Var
    • Configure WRFDA
    • Compile WRFDA
    • Clean Old Compilation
  • Running Observation Preprocessor (OBSPROC)
    • OBSPROC for 3DVAR
    • OBSPROC for 4DVAR
  • Running WRFDA
    • Download Test Data
    • Run a 3DVAR Test Case
    • Run a 4DVAR Test Case
  • Radiance Data Assimilation in WRFDA
    • Running WRFDA with Radiances
    • Reading Radiance Data in WRFDA
    • Radiative Transfer Models
    • Channel Selection
    • Bias Correction
    • Variational Bias Correction
    • VarBC Coldstart
    • Background Constraint for Bias Parameters
    • Scaling factor
    • Offline bias correction
    • Other Radiance Assimilation Options
    • Diagnostics and Monitoring
  • Radar Data Assimilation in WRFDA
    • Preparing Radar Obsevations
    • Running WRFDA for Radar Assimilation
    • Reflectivity Assimilation Options
    • Null-echo Assimilation Options
  • Precipitation Data Assimilation in WRFDA 4DVAR
    • Preparing Precipitation Observations
    • Running WRFDA with Precipitation Observations
    • Properly Linking Observation Files
  • Updating WRF Boundary Conditions
    • Lateral Boundary Conditions
    • Cycling with WRF and WRFDA
    • WRFDA 4DVAR with Lateral Boundary Conditions as Control Variables
  • Background Error (BE) and Running GEN_BE
    • Quick-start Guide: Running WRFDA with Different BE Options
    • Background Error Options in WRFDA
    • Generic BE Option: CV3
    • Domain-specific Background Error Options: Running GEN_BE
    • GEN_BE for CV6
    • Additional Background Error Options
  • WRFDA Diagnostics
  • Generating Ensembles with RANDOMCV
    • Running WRFDA for RANDOMCV
  • Hybrid Data Assimilation in WRFDA
    • Running the Hybrid System for 3DEnVar
    • Running the Hybrid System for 4DEnVar
    • Dual-resolution Hybrid
    • Hybrid Namelist Options
  • ETKF Data Assimilation
    • Source Code
    • Running the ETKF System
  • Multi-Resolution Incremental 4DVAR
  • Aerosol/Chemical Data Assimilation
  • Additional WRFDA Options
    • Wind Speed/Direction Assimilation
    • The Weak Penalty Constraint Option
    • Options for Improving Surface Data Assimilation
    • Divergence Constraint
    • Large-scale Analysis Constraint
  • WRFDA Description of Namelist Variables
    • &wrfvar1
    • &wrfvar2
    • &wrfvar3
    • &wrfvar4
    • &wrfvar5
    • &wrfvar6 (for minimization options)
    • &wrfvar7
    • &wrfvar8
    • &wrfvar9 (for program tracing)
    • &wrfvar10 (for code developers)
    • &wrfvar11
    • &wrfvar12
    • &wrfvar13
    • &wrfvar14 (radiance options)
    • &wrfvar15
    • &wrfvar16 (hybrid DA options)
    • &wrfvar17
    • &wrfvar18
    • &wrfvar19
    • &wrfvar20
    • &wrfvar21
    • &wrfvar22
    • &perturbation (settings related to 4DVAR options)
    • &radar_da (settings related to radar options)
  • OBSPROC Namelist Variables
    • &record1
    • &record2
    • &record3
    • &record4
    • &record5
    • &record6
    • &record7
    • &record8
    • &record9
• WRF-Fire
  • WRF-Fire in Idealized Cases
  • Fire Variables in namelist.input
    • &domains
    • &fire
  • namelist.fire
    • &fuel_scalars (Scalar Fuel Constants)
    • &fuel_categories (Domain Specifications)
  • Running WRF-Fire on Real Data
    • Building the code
    • Fire Variables in namelist.wps
    • Geogrid
    • Conversion to Geogrid Format
    • Editing GEOGRID.TBL
    • Ungrib and Metgrid
    • Running Real Case and WRF-Fire
  • Fire State Variables
  • WRF-Fire Software
    • WRF-Fire Coding Conventions
    • Parallel Execution
    • Software Layers
    • Initialization in Idealized Case
  • Firebrand Spotting Parameterization